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Exercise and Bone Health

Physical activity is an essential factor in bone health. The skeletal benefits of exercise have been demonstrated throughout the life cycle. Exercise can positively affect peak bone mass in children and adolescents; has been shown to help maintain or even modestly increase bone density in adulthood and; can assist in minimizing age related bone loss in older adults.

Exercise and Peak Bone Mass

By age 18, skeletal growth is nearly complete. The amount of peak bone mass achieved and the subsequent rate of bone loss are the key determinants of bone density later in life. There is substantial evidence that exercise plays an important role in the acquisition of bone mass in youth. Activities that are high impact and weight-bearing, such as running, jumping, soccer and volleyball, appear to be the most beneficial to the skeleton. The gains of such weight-bearing activity seem to be more pronounced in the peripheral skeleton than in the lumbar spine.

Muscle strengthening can also yield a bone-building effect. Even muscle activity in areas distant from the spine and hip can positively impact bone density at these sites. Not all physically active youth reap the skeletal benefits of exercise. Girls and young women who experience a disruption in the menstrual cycle from excessive exercise can endure bone loss that is never fully recovered (it is estimated that the prevalence of amenorrhea in female athletes ranges from 10-45 percent.) There is much concern that these young women are at an increased risk of stress fractures and fractures of the hip and spine.

Clearly, several factors other than exercise can affect peak bone mass. Hormonal status, body composition, nutritional intake and medication use are also important predictors of bone density.

Physical Activity in Adult Women

While 97% of bone mass is probably achieved by the age of eighteen, increases in bone density have been observed throughout the third decade of life. In some cases, even moderate increases in physical activity of women in their twenties can increase bone density and, potentially, decrease long-term fracture risk.

Most studies of pre-menopausal women demonstrate a positive bone benefit from exercise, with greater loading and higher impact activities producing the greatest skeletal benefit. The effects of physical activity tend to be the most pronounced among individuals who are the least active, an observation that has been made in other age groups, as well.

The Postmenopause and Beyond

Exercise continues to confer a skeletal benefit for many postmenopausal women. However, there is no evidence that physical activity alone is sufficient to fully offset the damaging effects of estrogen withdrawal in the first three to five years following menopause. Once the phase of accelerated bone loss is complete, regular exercise can have a protective effect on bone. As with other age groups, active postmenopausal women tend to have greater bone density than sedentary postmenopausal women.

Due to musculoskeletal concerns, older women are less likely to participate in higher impact activities. Regular activity such as walking, weight training and low impact aerobics can safely help to offset age-related bone loss, decrease fracture risk and improve the quality of life for older women.

Prevention of Falls and Fracture

Skeletal muscle mass and strength also decrease with age. Increased muscle weakness can compound the problem of low bone density by increasing the risk of falls and fracture. A multi-center study funded by the National Institute on Aging has evaluated the effects of intervention programs designed to minimize fracture risk in the elderly. The FICSIT trials (Frailty and Injuries: Cooperative Studies of Intervention Techniques) evaluated the effects of various physical activities in reducing the risk of falls. Strategies such as resistance training, computerized balance training and Tai Chi have shown promise as effective interventions for reducing falls and fall-related fractures.

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Fitness & Bone Health: The Skeletal Risk of Overtraining

Are you exercising too much? Eating too little? Have your periods become irregular or stopped? If so, you may be putting yourself at high risk for several serious health problems that could affect your health, your ability to remain active, and your risk for injuries. You also may be putting yourself at risk for developing osteoporosis, a disease in which bone density is decreased, leaving your bones vulnerable to fracture (breaking).

Why is missing my period such a big deal?

Some athletes see amenorrhea (the absence of menstrual periods) as a sign of appropriate levels of training. Others see it as a great answer to a monthly inconvenience. And some young women accept it blindly, not stopping to think of the consequences. But missing your menstrual periods is often a sign of decreased estrogen levels. And lower estrogen levels can lead to osteoporosis, a disease in which your bones become brittle and more likely to break.

Usually, bones become brittle and break when women are much older, but some young women, especially those who exercise so much that their periods stop, develop brittle bones and may start to have fractures at a very early age. Some 20-year-old female athletes have been described as "having the bones of an 80-year-old woman." Even if bones don't break when you're young, low estrogen levels during the peak years of bone-building, the pre-teen and teen years, can affect bone density for the rest of your life. And studies show that bone growth lost during these years may not ever be regained.

Broken bones don't just hurt--they can cause lasting deformities. Have you noticed that some older women and men have a stooped posture? This is not a normal sign of aging. Fractures from osteoporosis have left their spines permanently altered.

By the way, missing periods isn't the only problem. Not eating adequate amounts of calcium and vitamin D (among other nutrients) can also cause bone loss, and may lead to decreased athletic performance, decreased ability to exercise or train at desired levels of intensity or duration, and increased risk of injury.

Who is at risk for these problems?

Girls and women who may be trying to lose weight by restricting their eating and/or engaging in rigorous exercise regimes are at risk for these health problems. This may include serious athletes, "gym rats" (who spend considerable amounts of time and energy working out), and/or girls and women who believe "you can never be too thin."

How can I tell if someone I know, train with, or coach may be at risk for bone loss, fracture and other health problems?

Here are some signs to look for:

* missed or irregular menstrual periods
* extreme and/or "unhealthy-looking" thinness
* extreme or rapid weight loss
* frequent dieting behaviors such as:
  - eating very little
  - not eating in front of others
  - trips to the bathroom following meals
  - preoccupation with thinness or weight
  - focus on low-calorie and diet foods
  - possible increase in the consumption of water and other no- and low-calorie foods and beverages (possible increase in gum chewing, as well)
  - limiting diet to one food group or eliminating a food group
* frequent intense bouts of exercise such as:
  - continuous exercise or training sessions (e.g., taking an aerobics class, then running five miles, then swimming for an hour, followed by weight-lifting, etc.)
  - an "I can't miss a day of exercise/practice" attitude
  - an overly anxious preoccupation with an injury
  - exercising in spite of conditions that might lead others to "take the day off," including illness, inclement weather, injury, etc.
* high levels of self-criticism and/or self-dissatisfaction
* high levels of psychological or physical stress, such as:
  - depression
  - anxiety or nervousness
  - inability to concentrate
  - low levels of self-esteem
  - feeling cold all the time
  - problems sleeping
  - fatigue
  - injuries
  - talking about weight constantly

How can I make necessary changes in the interest of my bone health?

If you recognize some of these signs in yourself, the best thing you can do is to begin eating a more healthful diet, including enough calories to support your activity level. It's best to check with a doctor to make sure your missed periods aren't a sign of some other problem, and to get his or her help as you work toward a more healthy balance of food and exercise. Also, a doctor can help you take steps to protect your bones from further damage.

What can I do if I suspect a friend may have some of these signs?

First, be supportive. Approach your friend or teammate carefully and sensitively. She probably won't appreciate a lecture about how she should be taking better care of herself. But maybe you could share a copy of this brochure with her, or suggest that she talk to a trainer, coach, or doctor about the symptoms she's experiencing.

My friend drinks a lot of diet sodas. She says that this helps keep her trim.

Often, girls and women who may be dieting will drink diet sodas rather than much-needed milk. (Milk and other dairy products are a good source of calcium, an essential ingredient for healthy bones.) Drinking sodas instead of milk can be a problem, especially during the teen years when peak bone growth occurs. If you (or your friend) find yourself addicted to sodas, try drinking half as many sodas each day, and gradually add more milk and dairy products to your diet. A frozen yogurt shake can be an occasional low fat, tasty treat. Or try a fruit smoothie made with frozen yogurt, fruit, and/or calcium-enriched orange juice!


For Fitness Instructors and Trainers:

It's important for you to be aware of problems associated with bone loss in today's active young women. As an instructor or trainer, you are the one who sees, leads, and perhaps even evaluates the training sessions and performances of your clients. You may know best when something seems to be amiss. You also may be best for the role of helping a zealous female exerciser, who may be putting herself at risk for bone loss and other health problems, to recognize the risks of her behaviors and to help her establish new goals.

Trainers and instructors should also be aware of the implicit or explicit messages they send to their clients. An emphasis on health, strength, and fitness should be stressed, rather than an emphasis on thinness. Use caution when advising female clients to lose weight, and if such a recommendation is deemed necessary, education and assistance regarding proper, safe weight management should be offered by knowledgeable personnel. As an instructor or trainer, it's best to maintain a professional rapport with your clients, so they can feel comfortable approaching you with concerns about their exercise training programs, appropriate exercise goals and time lines, body image and nutrition issues, as well as more personal problems regarding eating practices and menstruation.

My coach and I think I should lose just a little more weight. I want to be able to excel at my sport!

Years ago, it was not unusual for coaches to encourage athletes to be as thin as possible for many sports (dancing, gymnastics, figure skating, swimming, diving, running, etc.). However, many coaches are realizing that being too thin is unhealthy and can negatively affect performance. It is important to exercise and watch what you eat. However, it's also important to develop and maintain healthy bones and bodies. Without these, it will not matter how fast you can run, how thin you are, or how long you exercise each day. Balance is the key!!!

I'm still not convinced. If my bones become brittle, so what? What's the worst thing that could happen to me?

Brittle bones may not sound as scary as some other fatal or rare disease. The fact is, osteoporosis can be very painful. It can cause disability. Imagine having so many spine fractures that you've lost inches in height and walk bent over. Imagine looking down at the ground everywhere you go because you can't straighten your back. Imagine not being able to find clothes that fit you. Imagine having difficulty breathing and eating because your lungs and stomach are compressed into a smaller space. Imagine having difficulty walking, let alone exercising, because of pain and deformity. Imagine constantly having to be aware of what you are doing and having to do things so slowly and carefully because of a very real fear and dread of a fracture...a fracture that could lead to a drastic change in your life - including pain, loss of independence, loss of mobility, loss of freedom and more.

But osteoporosis isn't just an "older person's" disease. Young women also experience fractures. Imagine being sidelined because of a broken bone and not being able to get those good feelings you get from regular activity.

Eating for Healthy Bones:

How much calcium do I need?

It is very important to your bone health that you receive adequate daily amounts of calcium, vitamin D, phosphorus, and magnesium. These are the vitamins and minerals that are most influential in building bones and teeth. This chart will help you decide how much calcium you need.


Recommended Calcium Intakes (mg/day)
Ages

9-19
14-18
19-30

Amount

1300
1300
1000

Source: National Academy of Sciences, 1997



Where can I get calcium and Vitamin D?

Dairy products are the primary food sources of calcium. Choose milk, yogurt, cheeses, ice cream, or products made or served with these choices to fulfill your daily requirement. Three servings of dairy products per day should give you at least 900 milligrams of calcium. Green vegetables are another source. A cup of broccoli, for example, has about 136 milligrams of calcium. Sunlight is one important source of vitamin D, but when the sun isn't shining, milk is also a good source of vitamin D.

Milk and Dairy Products

There are many great snack and meal items that contain calcium. With a little planning and "know how," you can make meals and snacks calcium-rich!

* Milk...Milk...Milk...
Wouldn't a tall, cold glass of this refreshing thirst quencher be great right now? If you're concerned about fat and calories, you can drink 1% or skim milk. You can drink it plain, or with a low/no-fat syrup or flavoring, such as chocolate syrup, vanilla extract, hazelnut flavoring, cinnamon, etc.

* Cheese is another winner...
Again, you can choose the low/no fat varieties. Use all different types of cheese for sandwiches, bagels, omelets, vegetable dishes, pasta creations...or as a snack by itself!

* Puddings (prepared with milk)...
You can now purchase (or make your own from a mix) a variety of flavors with little or no fat. Rocky road, butterscotch, vanilla, chocolate, pistachio....Try them all!

* Yogurt...
Add fruit. Eat it plain. Add a low/no fat sauce or syrup. No matter how you choose to eat this calcium-rich food, it remains a quick, easy, and convenient choice. It's also available in a variety of flavors. Try mocha-fudge-peppermint-swirl for the more adventurous at heart, and vanilla for the more traditional yogurt snacker!

* Frozen yogurt (or fat free ice cream)...
Everybody loves ice cream...And now, without the unnecessary fat grams, you can enjoy it more often! Mix yogurt, milk, and fruit to create a breakfast shake. Have a cone at lunchtime or as a snack. A scoop or two after dinner can be cool and refreshing.


What are other sources of calcium?

Many foods you already buy and eat may be "calcium-fortified". Try calcium-fortified orange juice or calcium-fortified cereal. Check food labels to see if some of your other favorite foods may be good sources of calcium. By the way, you can also take calcium supplements if you think you may not be getting enough from your diet.

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Questions and Answers about Arthritis and Exercise

This booklet answers general questions about arthritis and exercise. The amount and form of exercise recommended for each individual will vary depending on which joints are involved, the amount of inflammation, how stable the joints are, and whether a joint replacement procedure has been done. A skilled physician who is knowledgeable about the medical and rehabilitation needs of people with arthritis, working with a physical therapist also familiar with the needs of people with arthritis, can design an exercise plan for each patient.

What Is Arthritis?

There are over 100 forms of arthritis and other rheumatic diseases. These diseases may cause pain, stiffness, and swelling in joints and other supporting structures of the body such as muscles, tendons, ligaments, and bones. Some forms can also affect other parts of the body, including various internal organs.

Many people use the word "arthritis" to refer to all rheumatic diseases. However, the word literally means joint inflammation; that is, swelling, redness, heat, and pain caused by tissue injury or disease in the joint. The many different kinds of arthritis comprise just a portion of the rheumatic diseases. Some rheumatic diseases are described as connective tissue diseases because they affect the body's connective tissue--the supporting framework of the body and its internal organs. Others are known as autoimmune diseases because they are caused by a problem in which the immune system harms the body's own healthy tissues. Examples of some rheumatic diseases are:

  • Osteoarthritis
  • Rheumatoid arthritis
  • Fibromyalgia
  • Systemic lupus erythematosus
  • Scleroderma
  • Juvenile rheumatoid arthritis
  • Ankylosing spondylitis
  • Gout

Should People With Arthritis Exercise?

Yes. Studies have shown that exercise helps people with arthritis in many ways. Exercise reduces joint pain and stiffness and increases flexibility, muscle strength, cardiac fitness, and endurance. It also helps with weight reduction and contributes to an improved sense of well-being.

How Does Exercise Fit Into a Treatment Plan for People With Arthritis?

Exercise is one part of a comprehensive arthritis treatment plan. Treatment plans also may include rest and relaxation, proper diet, medication, and instruction about proper use of joints and ways to conserve energy (that is, not waste motion) as well as the use of pain relief methods.

What Types of Exercise Are Most Suitable for Someone With Arthritis?

Three types of exercise are best for people with arthritis:

  • Range-of-motion exercises (e.g., dance) help maintain normal joint movement and relieve stiffness. This type of exercise helps maintain or increase flexibility.

  • Strengthening exercises (e.g., weight training) help keep or increase muscle strength. Strong muscles help support and protect joints affected by arthritis.

  • Aerobic or endurance exercises (e.g., bicycle riding) improve cardiovascular fitness, help control weight, and improve overall function. Weight control can be important to people who have arthritis because extra weight puts extra pressure on many joints. Some studies show that aerobic exercise can reduce inflammation in some joints.

Most health clubs and community centers offer exercise programs for people with physical limitations.

How Does a Person With Arthritis Start an Exercise Program?

People with arthritis should discuss exercise options with their doctors and other health care providers. Most doctors recommend exercise for their patients. Many people with arthritis begin with easy, range-of-motion exercises and low-impact aerobics. People with arthritis can participate in a variety of, but not all, sports and exercise programs. The doctor will know which, if any, sports are off-limits.

The doctor may have suggestions about how to get started or may refer the patient to a physical therapist. It is best to find a physical therapist who has experience working with people who have arthritis. The therapist will design an appropriate home exercise program and teach clients about pain-relief methods, proper body mechanics (placement of the body for a given task, such as lifting a heavy box), joint protection, and conserving energy.

Step Up to Exercise: How To Get Started

  • Discuss exercise plans with your doctor.

  • Start with supervision from a physical therapist or qualified athletic trainer.

  • Apply heat to sore joints (optional; many people with arthritis start their exercise program this way).

  • Stretch and warm up with range-of-motion exercises.

  • Start strengthening exercises slowly with small weights (a 1- or 2-pound weight can make a big difference).

  • Progress slowly.

  • Use cold packs after exercising (optional; many people with arthritis complete their exercise routine this way).

  • Add aerobic exercise.

  • Consider appropriate recreational exercise (after doing range-of-motion, strengthening, and aerobic exercise). Fewer injuries to joints affected by arthritis occur during recreational exercise if it is preceded by range-of-motion, strengthening, and aerobic exercise that gets your body in the best condition possible.

  • Ease off if joints become painful, inflamed, or red, and work with your doctor to find the cause and eliminate it.

  • Choose the exercise program you enjoy most and make it a habit.

What Are Some Pain Relief Methods for People With Arthritis?

There are known methods to help stop pain for short periods of time. This temporary relief can make it easier for people who have arthritis to exercise. The doctor or physical therapist can suggest a method that is best for each patient. The following methods have worked for many people:

  • Moist heat supplied by warm towels, hot packs, a bath, or a shower can be used at home for 15 to 20 minutes three times a day to relieve symptoms. A health professional can use short waves, microwaves, and ultrasound to deliver deep heat to noninflamed joint areas. Deep heat is not recommended for patients with acutely inflamed joints. Deep heat is often used around the shoulder to relax tight tendons prior to stretching exercises.

  • Cold supplied by a bag of ice or frozen vegetables wrapped in a towel helps to stop pain and reduce swelling when used for 10 to 15 minutes at a time. It is often used for acutely inflamed joints. People who have Raynaud's phenomenon should not use this method.

  • Hydrotherapy (water therapy) can decrease pain and stiffness. Exercising in a large pool may be easier because water takes some weight off painful joints. Community centers, YMCAs, and YWCAs have water exercise classes developed for people with arthritis. Some patients also find relief from the heat and movement provided by a whirlpool.

  • Mobilization therapies include traction (gentle, steady pulling), massage, and manipulation (using the hands to restore normal movement to stiff joints). When done by a trained professional, these methods can help control pain and increase joint motion and muscle and tendon flexibility.

  • TENS (transcutaneous electrical nerve stimulation) and biofeedback are two additional methods that may provide some pain relief, but many patients find that they cost too much money and take too much time. In TENS, an electrical shock is transmitted through electrodes placed on the skin's surface. TENS machines cost between $80 and $800. The inexpensive units are fine. Patients can wear them during the day and turn them off and on as needed for pain control.

  • Relaxation therapy also helps reduce pain. Patients can learn to release the tension in their muscles to relieve pain. Physical therapists may be able to teach relaxation techniques. The Arthritis Foundation has a self-help course that includes relaxation therapy. Health spas and vacation resorts sometimes have special relaxation courses.

  • Acupuncture is a traditional Chinese method of pain relief. A medically qualified acupuncturist places needles in certain sites. Researchers believe that the needles stimulate deep sensory nerves that tell the brain to release natural painkillers (endorphins). Acupressure is similar to acupuncture, but pressure is applied to the acupuncture sites instead of using needles.

How Often Should People With Arthritis Exercise?

  • Range-of-motion exercises can be done daily and should be done at least every other day.

  • Strengthening exercises should be done every other day unless you have severe pain or swelling in your joints.

  • Endurance exercises should be done for 20 to 30 minutes three times a week unless you have severe pain or swelling in your joints. According to the American College of Rheumatology, 20- to 30-minute exercise routines can be performed in increments of 10 minutes over the course of a day.

What Type of Strengthening Program Is Best?

This varies depending on personal preference, the type of arthritis involved, and how active the inflammation is. Strengthening one's muscles can help take the burden off painful joints. Strength training can be done with small free weights, exercise machines, isometrics, elastic bands, and resistive water exercises. Correct positioning is critical, because if done incorrectly, strengthening exercises can cause muscle tears, more pain, and more joint swelling.

Are There Different Exercises for People With Different Types of Arthritis?

There are many types of arthritis. Experienced doctors, physical therapists, and occupational therapists can recommend exercises that are particularly helpful for a specific type of arthritis. Doctors and therapists also know specific exercises for particularly painful joints. There may be exercises that are off-limits for people with a particular type of arthritis or when joints are swollen and inflamed. People with arthritis should discuss their exercise plans with a doctor. Doctors who treat people with arthritis include rheumatologists, orthopaedic surgeons, general practitioners, family doctors, internists, and rehabilitation specialists (physiatrists).

How Much Exercise Is Too Much?

Most experts agree that if exercise causes pain that lasts for more than 1 hour, it is too strenuous. People with arthritis should work with their physical therapist or doctor to adjust their exercise program when they notice any of the following signs of strenuous exercise:

  • Unusual or persistent fatigue
  • Increased weakness
  • Decreased range of motion
  • Increased joint swelling
  • Continuing pain (pain that lasts more than 1 hour after exercising)

Should Someone With Rheumatoid Arthritis Continue To Exercise During a General Flare? How About During a Local Joint Flare?

It is appropriate to put joints gently through their full range of motion once a day, with periods of rest, during acute systemic flares or local joint flares. Patients can talk to their doctor about how much rest is best during general or joint flares.

Are Researchers Studying Arthritis and Exercise?

Researchers are looking at the effects of exercise and sports on the development of musculoskeletal disabilities, including arthritis. They have found that people who do moderate, regular running have low, if any, risk of developing osteoarthritis. However, studies show that people who participate in sports with high-intensity, direct joint impact are at risk for the disease. Examples are football and soccer. Sports involving repeated joint impact and twisting (such as baseball and soccer) also increase osteoarthritis risk. Early diagnosis and effective treatment of sports injuries and complete rehabilitation should decrease the risk of osteoarthritis from these injuries.

Researchers also are looking at the effects of muscle strength on the development of osteoarthritis. Studies show, for example, that strengthening the quadriceps muscles can reduce knee pain and disability associated with osteoarthritis. One study shows that a relatively small increase in strength (20-25 percent) can lead to a 20-30 percent decrease in the chance of developing knee osteoarthritis. Other researchers continue to look for and find benefits from exercise to patients with rheumatoid arthritis, spondyloarthropathies, systemic lupus erythematosus, and fibromyalgia. They are also studying the benefits of short- and long-term exercise in older populations.

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Questions and Answers: Physical Activity and Cancer

What is physical activity?

Physical activity is any bodily movement produced by skeletal muscles; such movement results in an expenditure of energy. Physical activity is a critical component of energy balance, a term used to describe how weight, diet, and physical activity influence health, including cancer risk.

How is physical activity related to health?

Researchers have established that regular physical activity can improve health by:

  • helping to control weight,
  • maintaining healthy bones, muscles and joints,
  • reducing the risk of developing high blood pressure and diabetes,
  • promoting psychological well-being,
  • reducing the risk of death from heart disease, and
  • reducing the risk of premature death .

In addition to these health benefits, researchers are learning that physical activity can also affect the risk of cancer. There is convincing evidence that physical activity is associated with a reduced risk of cancers of the colon and breast . Several studies also have reported links between physical activity and a reduced risk of cancers of the prostate, lung and lining of the uterus (endometrial cancer). Despite these health benefits, recent studies have shown that more than 60 percent of Americans do not engage in enough regular physical activity .

How much physical activity do adults need?

The Centers for Disease Control and Prevention (CDC) recommend that adults: " engage in moderate-intensity physical activity for at least 30 minutes on five or more days of the week, or " engage in vigorous-intensity physical activity for at least 20 minutes on three or more days of the week. Examples of moderate-intensity and vigorous-intensity physical activities can be found on the CDC Physical Activity Page.

What is the relationship between physical activity and colon cancer risk?

Individuals who are physically active can reduce their risk of developing colon cancer by 40 percent to 50 percent, with the greatest reduction in risk among those who are most active. A decreased risk of colon cancer has been consistently reported for physically active men. Many studies have reported a reduction in colon cancer risk for physically active women . The relationship between physical activity and risk in women, however, has been less consistent . Physical activity most likely influences the development of colon cancer through multiple, perhaps overlapping, biological pathways. Many researchers believe physical activity aids in regular bowel movements, which may decrease the time the colon is exposed to potential carcinogens . Increased physical activity also causes changes in insulin resistance, metabolism, and hormone levels, which may help prevent tumor development . Physical activity has also been found to alter a number of inflammatory and immune factors, some of which may influence colon cancer risk.

How can physical activity reduce breast cancer risk?

Physically active women have up to a 40 percent reduced risk of developing breast cancer . Most evidence suggests that physical activity reduces breast cancer risk in both premenopausal and postmenopausal women . Although a lifetime of regular, vigorous activity is thought to be of greatest benefit, women who occasionally engage in physical activity also experience a reduced risk compared to inactive women . A number of studies also suggest that the effect of physical activity may be different across levels of BMI, with the greatest benefit seen in women in the normal weight range (generally a BMI under 25 kg/m-squared). For example, a recent major report from the Women's Health Initiative found that among postmenopausal women, walking 30 minutes per day was associated with a 20 percent reduction in breast cancer risk. The health benefits of physical activity were greatest among women who were of normal weight; they experienced a 37 percent decrease in risk. The protective effect of physical activity was not found among overweight or obese women. Researchers have proposed several biological mechanisms that may explain the relationship between physical activity and breast cancer development. Physical activity causes changes in hormone metabolism, body mass, and immune function, which may prevent tumor development.

How might physical activity reduce prostate cancer risk?

Physical activity probably reduces men's risk for prostate cancer by 10 percent to 30 percent. The likely association between physical activity and prostate cancer is based on a small number of studies that evaluated the role of physical activity in men who developed prostate cancer. Most of these studies indicate that inactive men have higher rates of prostate cancer compared to men who are very physically active . While it is probable that men who are physically active experience a reduction in risk for prostate cancer, the potential biological mechanisms that may explain this association are unknown.

How might physical activity reduce endometrial cancer risk?

Studies also suggest that women who are physically active have a 30 percent to 40 percent reduced risk of endometrial cancer , with the greatest reduction in risk among those who are most active. The possible association between physical activity and endometrial cancer is based on a limited number of studies, some of which indicate that inactive women have higher rates of endometrial cancer compared to physically active women. Changes in body mass and alterations in level and metabolism of sex hormones, such as estrogen, are the major biological mechanisms thought to explain the association between physical activity and endometrial cancer. A few studies have examined whether the effect of physical activity varies according to the weight of the woman, but the results have been inconsistent.

How might physical activity reduce lung cancer risk?

It is possible that individuals who are physically active have a 30 percent to 40 percent reduced risk of developing lung cancer . The possible link between physical activity and lung cancer is based on a limited number of studies that have found higher rates of lung cancer among those who are physically inactive compared to those who are active, after accounting for smoking status. The relationship between physical activity and lung cancer risk is less clear for women than it is for men .

However, the results of many of these studies are difficult to interpret because smokers who are able to engage in physical activity may have much better lung function. Investigators hypothesize that improvements in pulmonary function and ventilation in active, compared to inactive individuals, may explain the possible association between lung cancer and reduced physical activity .

Is NCI exploring the role of physical activity in the quality of life and prognosis of cancer patients?

NCI-funded studies are exploring the ways in which physical activity may improve the quality of life of cancer patients and survivors. One study is examining the feasibility and benefits of a home-based moderate exercise program among breast cancer survivors (home-based). Another is testing the effectiveness of a nurse-directed walking exercise program to mitigate fatigue and maintain physical functioning during treatment for prostate, breast, or colorectal cancer.

What are some examples of NCI studies investigating the role of physical activity in cancer risk?

A number of NCI-funded studies are answering questions about the relationship between physical activity and the risk of developing cancer. For example, one study is investigating whether women who engage in moderate and strenuous physical activity have a reduced risk of endometrial and ovarian cancer, and if strenuous physical activity reduces this risk more than moderate physical activity. Another is examining the effect of one year of moderate aerobic and strength training exercise among patients with colorectal polyps.

Do any of these studies focus on special populations who are at increased risk of cancer?

NCI funds a number of research projects and interventions aimed at helping vulnerable populations reduce their risk for cancer by becoming more active, changing their nutritional behavior, and/or maintaining an optimal weight. Populations included in these projects include multiethnic working poor populations, African-American women, African-American church communities, rural church communities, overweight women, overweight men, and adolescents. For example, one study involving rural churches is exploring methods of helping participants to change their nutrition, activity, and exercise patterns to meet cancer risk reduction guidelines.

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Did you know?

Being healthy and active can help you stay fit and feel fabulous over the years. If you are overweight and inactive, you are more likely to get:

  • Type 2 diabetes (high blood sugar)
  • High blood pressure
  • Heart disease
  • Stroke
  • Certain forms of cancer.

You can improve your health if you Move More and Eat Better! This booklet gives you tips on how to get moving and eat well throughout your life.

Why Move More and Eat Better?

Being active and making smart food choices is good for your health. But that’s not the only reason to move more and eat better. You can:

  • Have more energy
  • Reduce stress
  • Feel better about yourself
  • Relieve boredom or depression
  • Set an example for your family.

Tips on Moving More

Try to do at least 30 minutes of moderate-intensity physical activity (like brisk walking) most days of the week. It is not as hard as you may think, and you do not have to do the whole 30 minutes at on time. Try these tips to get past things that keep you from being active.

"It's too late for me to get physically active."

It is never too late to start moving more. Physical activity can help you manage health problems like arthritis, osteoporosis (bone loss), and heart disease. It may also help:

  • Keep your body flexible
  • Keep your bones and muscles strong
  • Keep your heart and lungs healthy
  • Control high blood sugar, especially if you lose weight
  • Let you keep living in your own home without help.

TIP: If you are over 50 or have chronic health problems such as heart disease, high blood pressure, diabetes, osteoporosis, or obesity, talk to your health care provider before starting a vigorous physical activity program. You do not need to talk to your provider before starting less strenuous activity like walking.

"Physical activity is a chore."

  • Walk or take an exercise class with a friend or a group—that way, you can cheer each other on, have company, and feel safer when you are outdoors.

  • Start a small garden in your yard or a community garden.

  • Break it up into short blocks of time – taking three 10-minute walks during your day may be easier than taking one 30-minute walk.

  • Do stretches or walk in place while watching TV.

"its too expensive."

There are lots of ways to be physically active that are free or low-cost. You can:

  • Find a local park or school track where you can walk.

  • Walk around a mall.

  • Join a recreation center or fitness center at work or near your home.

  • Be active with your grandchildren —take a walk, toss a softball, or ride bikes. Physical activity is good for them too.

  • Walk your dog. If you do not have a dog, pretend that you do.

Tips on Eating Better

You may not know where to start on the road to making healthier food choices. Try these tips to eat better, save time, and stretch your food budget.

Get started on eating well

These tips can help you have healthy eating habits:

  • Start every day with breakfast. Try oatmeal, a whole-grain cereal like raisin bran with nonfat or low-fat milk, whole wheat toast spread with jam, or nonfat or low-fat yogurt. Enjoy some fruit with your breakfast too.

  • Try kidney or butter beans in hot dishes, on salads, or plain. Protein is important to your health as you age. Beans are loaded with protein and cost less than meat.

  • Choose nonfat or low-fat milk, yogurt, and cheese instead of full fat dairy products.

  • Choose whole-grain foods like whole wheat bread, oatmeal, brown rice, and whole wheat pasta more often than refined-grain foods, like white bread, white rice, and white pasta. Whole-grain foods offer dietary fiber, which helps keep you regular.

  • Do not let sweets like cookies, candy, or soda crowd out healthy foods.

TIP: If you cannot digest lactose (the sugar found in milk) try nonfat or low-fat lactose-reduced milk. Or try nonfat or low-fat yogurt or hard cheeses like cheddar, which may be easier to digest than milk. You can also get the calcium from calcium-fortified juices, soy-based beverages, and cereals. Eating dark leafy vegetables like collard greens and kale, and canned fish with soft bones like salmon, can also help you meet your body's calcium needs.

Make healthy meals that taste good

You might like the taste of fried foods and fatty meats, but these foods can put too much saturated fat in your diet if you eat them too often or in large amounts. Saturated fat is not healthy for your heart. There are other ways you can add flavor to your food. Try:

  • Baking, roasting, broiling, grilling, or oven-frying chicken or fish – season with herbs, spices, lemon, lime, or vinegar (but not salt)

  • Cooking collard greens or kale with onions, garlic, chicken broth, bouillon, smoked turkey, turkey bacon, or turkey ham (use broth, bouillon, and cured meats in small amounts because they are high in sodium)

  • Topping baked potatoes with salsa or low-fat sour cream

  • Making salads and casseroles with low-fat or nonfat salad dressing or mayonnaise, flavored vinegar like balsamic, or a small amount of mustard (mustard is high in sodium).

Save time and money when you cook

You do not have to spend a lot of time in the kitchen or a lot of money to eat well.

  • Cook enough to last. Casseroles, meat loaf, and whole cooked chicken can last for several days. (Be sure to freeze or refrigerate leftovers right away to keep them safe to eat.)

  • Buy frozen or canned vegetables (no salt added) and canned fruit packed in juice. They are just as good for you as fresh produce, will not go bad, and make quick and easy additions to your meals.

  • If your local store does not have the foods you want or their prices are too high, go to another store. Start a weekly shopping carpool, share the cost of a taxi with friends, or ask a relative or neighbor for a ride.
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    Reading Food Labels

    Food labels may help you make smart choices. But they can be confusing. Here are some quick tips for reading food labels:*

    Serving Size: All the information on a food label is based on the serving size. Be careful—one serving may be much smaller than you think. Compare what you eat to the serving size on the label.

    Calories: Most women need to eat almost 1,600 calories per day, with no more than 30% (about 480 calories) from total fat.**

    % Daily Value (%DV): This tells you if a food is high or low in nutrients. Foods that have more than 20 percent daily value (20% DV) of a nutrient are high. Foods that have 5 percent daily value (5% DV) or less are low.

    Saturated Fat: Saturated fat is not healthy for your heart. Compare labels on similar foods and try to choose foods with a 5% DV or less for saturated fat.***

    Trans Fat: Trans fat is not healthy for your heart. When reading food labels, add together the grams (g) of trans fat and saturated fat, and choose foods with the lowest combined amount.

    Cholesterol: Too much cholesterol is not healthy for your heart. Keep your intake of saturated fat, trans fat, and cholesterol as low as possible.

    Sodium: Salt contains sodium. High sodium intake is linked to higher blood pressure. Foods that contain more than 20% DV are high in sodium. Look for labels that say “sodium-free” or “low sodium.” Foods that are low in sodium contain no more than 5% DV for sodium.

    TIP: Many food labels say “low-fat,” “reduced fat,” or “light.” That does not always mean the food is low in calories. Remember, fat free does not mean calorie free and calories do count!

    Fiber: Choose foods that are rich in fiber, such as whole grains, fruits, and vegetables.

    Sugar: Try to choose foods with little or no added sugar (like low-sugar cereals).

    Calcium: Choose foods that are high in calcium. Foods that are high in calcium have at least 20% DV.

     

    * For more information on reading nutrition labels, see Using the Dietary Guidelines for Americans, available from the Federal Consumer Information Center, 1-888-878-3256 or read Guidance on How to Understand and Use the Nutrition Facts Panel on Food Labels from the Food and Drug Administration (FDA) at www.cfsan.fda.gov/~dms/foodlab.html.

    ** From Dietary Guidelines for Americans, 2000, U.S. Department of Agriculture and U.S. Department of Health and Human Services. If you need a special diet, check with your health care provider before following these guidelines.

    ***Ibid.

    Keeping Track of Serving Sizes

    Many people think that bigger is better. We are so used to value-sized portions—especially in restaurants—that it is easy to eat more than our bodies need. Eating smaller portions will help you cut down on calories and fat (and might save money, too). Here is a 1,600 calorie sample menu with sensible portion sizes:*

    Breakfast 1/2 cup oatmeal 1 English muffin with 1 tablespoon low-fat cream cheese 1 cup low-fat milk 3/4 cup orange juice

    Lunch 2 ounces baked chicken without skin (a little smaller than a deck of cards) Lettuce, tomato, and cucumber salad with 2 teaspoons oil and vinegar dressing 1/2 cup rice seasoned with 1/2 teaspoon tub or liquid margarine 1 small whole wheat roll with 1 teaspoon margarine

    TIP: Try keeping a food diary. Writing down what you eat, when you eat, and how you feel when you eat can help you understand your eating habits. You may be able to see ways to make your eating habits healthier. You can also use your diary to plan weekly menus, make shopping lists, and keep track of recipes you would like to try. For more information about keeping track of food portions, read WIN’s brochure, Just Enough for You.

    Dinner 3 ounces lean roast beef (about the size of a deck of cards) with 1 tablespoon beef gravy 1/2 cup turnip greens seasoned with 1/2 teaspoon margarine 1 small baked sweet potato with 1/2 teaspoon margarine 1 slice cornbread 1/4 honeydew melon

    Snack 2 1/2 cups low-fat microwave popcorn 1 1/2 teaspoons margarine

    TIP: Use tub or liquid margarine instead of butter. Choose a soft margarine that has no more than 2 grams of saturated fat per tablespoon and that lists "liquid vegetable oil" as the first ingredient on the ingredient list. American Heart Association

    * Adapted from National Heart, Lung, and Blood Institute sample menus.

    Eating Away From Home

    In real life, you cannot always cook your meals. Here are some ways to make healthy choices when you are away from home:

    • Use a small plate at social functions to help keep you from eating too much.

    • At restaurants, order a half portion, share a meal with a friend, or take half of your order home for another meal.

    • Balance your meals throughout the day. If you have a high-fat or high-calorie breakfast or lunch, make sure you eat a low-fat dinner. If you know you will be having a higher fat dinner, make lower fat choices earlier in the day.

    You Can Do It!

    Set goals. Move at your own pace. Celebrate your successes. Allow for setbacks. Let your family and friends help you. And keep trying—you can do it!

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    Why walk?

    Walking is one of the easiest ways to be physically active. You can do it almost anywhere and at any time. Walking is also inexpensive. All you need is a pair of shoes with sturdy heel support. Walking will:

    • Give you more energy
    • Make you feel good
    • Help you to relax
    • Reduce stress
    • Help you sleep better
    • Tone your muscles
    • Help control your appetite
    • Increase the number of calories your body uses.

    For all these reasons, people have started walking programs. If you would like to start your own program, read and follow the information provided in this pamphlet.

    Is it okay for me to walk?

    Answer the following questions before you begin a walking program.

    • Has your health care provider ever told you that you have heart trouble?
    • When you are physically active, do you have pains in your chest or on your left side (neck, shoulder, or arm)?

    • Do you often feel faint or have dizzy spells?

    • Do you feel extremely breathless after you have been physically active?

    • Has your health care provider told you that you have high blood pressure?

    • Has your health care provider told you that you have bone or joint problems, like arthritis, that could get worse if you are physically active?

    • Are you over 50 years old and not used to a lot of physical activity?

    • Do you have a health problem or physical reason not mentioned here that might keep you from starting a walking program?

    If you answered yes to any of these questions, please check with your health care provider before starting a walking program or other form of physical activity.

    How do I start a walking program?

    Leave time in your busy schedule to follow a walking program that will work for you. In planning your walking program, keep the following points in mind:

    • Choose a safe place to walk. Find a partner or group of people to walk with you. Your walking partner(s) should be able to walk with you on the same schedule and at the same speed.

    • Wear shoes with thick flexible soles that will cushion your feet and absorb shock.

    • Wear clothes that will keep you dry and comfortable. Look for synthetic fabrics that absorb sweat and remove it from your skin.

    • For extra warmth in winter, wear a knit cap. To stay cool in summer, wear a baseball cap or visor.

    • Do light stretching before and after you walk.

    • Think of your walk in three parts. Walk slowly for 5 minutes. Increase your speed for the next 5 minutes. Finally, to cool down, walk slowly again for 5 minutes.

    • Try to walk at least three times per week. Add 2 to 3 minutes per week to the fast walk. If you walk less than three times per week, increase the fast walk more slowly.

    • To avoid stiff or sore muscles or joints, start gradually. Over several weeks, begin walking faster, going further, and walking for longer periods of time.

    • The more you walk, the better you will feel. You also will use more calories.

    A sample walking program and examples of easy stretches are shown on the back.

    Safety tips

    Keep safety in mind when you plan your route and the time of your walk.

    • Walk in the daytime or at night in well-lighted areas.
    • Walk in a group at all times.
    • Notify your local police station of your group’s walking time and route.
    • Do not wear jewelry.
    • Do not wear headphones.
    • Be aware of your surroundings.

    How do I warm up?

    Before you start to walk, do the stretches shown here. Remember not to bounce when you stretch. Perform slow movements and stretch only as far as you feel comfortable.

    Illustration demonstrating sidestrechSide Reaches

    Reach one arm over your head and to the side. Keep your hips steady and your shoulders straight to the side. Hold for 10 seconds and repeat on the other side.

    Illustration demonstrating the knee pullKnee Pull

    Lean your back against a wall. Keep your head, hips, and feet in a straight line. Pull one knee to your chest, hold for 10 seconds, then repeat with the other leg.

    Illustration demonstrating the wall pushWall Push

    Lean your hands on a wall with your feet about 3-4 feet away from the wall. Bend one knee and point it toward the wall. Keep your back leg straight with your foot flat and your toes pointed straight ahead. Hold for 10 seconds and repeat with the other leg.

    Illustration demonstrating the leg curlLeg Curl

    Pull your right foot to your buttocks with your right hand. Keep your knee pointing straight to the ground. Hold for 10 seconds and repeat with your left foot and hand.

     

     

     

    Taking the first step

    Sample walking programWalking right is very important.

    • Walk with your chin up and your shoulders held slightly back.

    • Walk so that the heel of your foot touches the ground first. Roll your weight forward.

    • Walk with your toes pointed forward.

    • Swing your arms as you walk.

     

     

     

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Fitness