Exercise and prostate cancer

Nancy Ferrari

Senior editor, Harvard Health

By now, we’ve all heard about the value of exercise in maintaining good health. Literally hundreds of studies conducted over more than half a century demonstrate that regular exercise pares down your risk of developing some deadly problems, including heart disease, stroke, and certain types of cancer (colorectal cancer, for example). It also eases the toll of chronic ailments like high blood pressure, diabetes, and arthritis. What may come as a surprise is that regular physical activity may actually help prevent some prostate disorders and improve prostate health. Emerging scientific evidence suggests that engaging in a few hours of exercise a week may help keep prostate tumors from advancing — or prevent them from developing in the first place.

Note: Talk with your doctor before starting an exercise program. He or she can help you design a routine to meet your needs and make sure that you are exercising safely.

Assessing the evidence

Some studies have suggested that more physically active men may have a lower risk of prostate cancer — or prostate cancer progression — than sedentary men, but the results have been less clear-cut than with other prostate-related conditions. One of the earlier studies of exercise, the Harvard Alumni Study, found no significant association between physical activity and prostate cancer risk. Later, other Harvard researchers analyzed data from the Health Professionals Follow-up Study to determine the number of cases of prostate cancer among 47,620 men over a 14-year period and to look for associations between cancer and physical activity. They found no evidence that moderate physical activity lowers overall prostate cancer risk. (See “Exercise and prostate cancer development and progression,” below.)

The researchers then looked at the impact of vigorous activity on different types of prostate cancer (local and advanced, for example) at various ages. They found that men ages 65 or older who engaged in at least three hours of vigorous physical activity a week reduced their risk of being diagnosed with high-grade, advanced, or fatal prostate cancer by nearly 70%. But vigorous exercise did not seem to protect against prostate cancer in men younger than 65.

The findings were consistent with an earlier study by the American Cancer Society, which followed 72,174 men for nine years. Researchers found no difference in the overall risk of prostate cancer between men who engaged in the most physical activity and those who reported no physical activity. But when it came to aggressive prostate cancer, physical activity appeared protective: men who got the most exercise were 31% less likely to develop aggressive disease than men who opted for the sofa. A 2006 Norwegian study yielded a similar result.

A 2005 San Francisco study took a slightly different tack in examining the exercise-cancer relationship. Rather than follow participants over time, researchers randomly assigned 93 men with low-grade prostate cancer who were pursuing active surveillance to one of two groups: a control group that received standard care and an experimental group that was asked to make comprehensive lifestyle changes, including the initiation of an exercise program. After one year, six patients in the control group (versus none of the patients in the experimental group) underwent conventional prostate cancer treatment due to PSA increases or disease progression. PSA scores increased by 6% in the control group, but dropped by 4% in the lifestyle-modification group. Although the study included a relatively small number of participants who made multiple lifestyle changes (significant alterations in diet, for example), it leaves open the possibility that exercise may slow the progression of low-grade prostate cancer.

Studies have more definitively concluded, however, that exercise can improve quality of life and, perhaps paradoxically, reduce fatigue in prostate cancer patients. For example, patients undergoing radiation therapy for localized prostate cancer who participated in a cardiovascular exercise program for eight weeks improved their cardiovascular fitness, flexibility, muscle strength, and overall quality of life. They also experienced less fatigue than patients who didn’t exercise.

Importantly, researchers have found that the exercise need not be vigorous to offer benefits. Scottish researchers determined that moderate-intensity walking produced a significant improvement in physical functioning with no significant increase in fatigue. Improved physical functioning, they wrote, may be necessary to combat the fatigue that comes with radiation therapy.

Exercise is beneficial, too, for men on androgen deprivation therapy (also called hormone therapy) for advanced prostate cancer. Hormone therapy commonly causes metabolic changes that lead to weight gain and up the risk for diabetes and heart attack. It has also been linked to bone loss. Regular exercise helps combat these side effects.

Exercise and prostate cancer development and progression

Giovannucci EL, Liu Y, Leitzmann MF, et al. A Prospective Study of Physical Activity and Incident and Fatal Prostate Cancer. Archives of Internal Medicine 2005;165:1005–10. PMID: 15883238.

Lee IM, Paffenbarger RS. Physical Activity and Its Relation to Cancer Risk: A Prospective Study of College Alumni. Medicine and Science in Sports and Exercise 1994;26:831–37. PMID: 7934755.

Nilsen TI, Romundstad PR, Vatten LJ. Recreational Physical Activity and Risk of Prostate Cancer: A Prospective Population-Based Study in Norway (the HUNT Study). International Journal of Cancer 2006;119:2943–47. PMID: 17019717.

Ornish, D, Weidner G, Fair WR, et al. Intensive Lifestyle Changes May Affect the Progression of Prostate Cancer. Journal of Urology 2005;174:1065–69. PMID: 16094059.

Patel AV, Rodriguez C, Jacobs EJ, et al. Recreational Physical Activity and Risk of Prostate Cancer in a Large Cohort of U.S. Men. Cancer Epidemiology, Biomarkers, and Prevention 2005;14:275–79. PMID: 15668508.

Reaping the benefits

So how much exercise should you do if you’re concerned about prostate cancer? What activities can you do? Do you have to take up jogging? Must you spend hours huffing and puffing on a treadmill at a gym to keep your prostate healthy?

There is no specific exercise program for men who have been diagnosed with prostate cancer or who are at high risk of the disease. But a well-rounded exercise program that includes just half an hour of physical activity on all or most days of the week delivers solid health benefits. And you needn’t perform this activity all at once; you can break it up into three 10-minute segments. Aim for a moderate pace. A good guideline: you should be able to carry on a conversation — yes, short sentences are okay — while exercising. If you’re breathing too hard to talk comfortably, back off. When an activity becomes easy, boost the length of your workout or your speed. (For more on how hard to work, see “What about my heart rate?” below.)

If you want, you can jog or use the treadmill at the gym (see “Health club savvy,” below). But keep in mind that bicycling (see “Your bike seat and your health,” below), swimming, or even taking brisk walks around the block will do the trick. In fact, walking has been touted as a nearly perfect exercise because people of all ages and fitness levels can do it. Walking is also safe for nearly everyone. It doesn’t jar joints or raise the heart rate to a level that would be dangerous, even for someone who is not in good shape.

What about my heart rate?

Many people have been taught to measure their pulse during an aerobic workout to see whether they’ve reached a target heart rate. To figure your maximum heart rate, subtract your age from 220. Multiply the result by 50% for the low end of your target range or by 75% for the high end.

There are drawbacks to this technique, however. Few people take their pulse accurately enough to make the effort worthwhile. And since your pulse drops rapidly when you’re not exercising, measuring it after you’ve stopped won’t say much about your true level of exertion. Simply paying attention to your body’s signals, such as how hard you are breathing, will tell you whether you can work harder or should slow down.

Health club savvy

While you don’t need to join a health club to exercise, membership does have some advantages. You’ll have access to a wide variety of equipment and exercise classes, so it’s easy to change your routine and avoid boredom. Personal trainers can help you devise a routine and teach you how to use the equipment properly. And many people find that joining a gym motivates them to exercise frequently because they want to get their money’s worth.

On the other hand, memberships are often expensive, though some insurance companies will reimburse part or all of the cost. In addition, some gyms are so crowded that you may not get into the classes you want, or you may have to wait in line to use a piece of equipment.

Before joining, tour a gym at the times you’re likely to use it so you can see what the atmosphere will be like. Make sure the location and hours work with your schedule. If you want to work regularly with a trainer, ask about any additional fees and about the trainer’s qualifications. Look for trainers who have been certified by a professional organization, such as the American College of Sports Medicine.

Your bike seat and your health

A sustained ride on a narrow bicycle seat compresses the nerves in the perineum, the area between the scrotum and the anus, leading to numbness in the penis. Rarely, impotence occurs. The problem can last from a week to a month after a lengthy bike ride. Taking the following precautions can help you avoid these problems:

  • Pick a wide seat with plenty of padding. Look for gel-filled and anatomy-friendly seats.
  • Wear padded bike shorts.
  • Don’t tilt your seat forward. This increases pressure on the perineum.
  • Make sure the seat height is correct. Your legs should not be completely extended at the bottom of your pedal stroke.
  • Raise the handlebars so your position is more upright.
  • Be sure the top bar of the frame is at least two inches below your crotch. Cover the bar with padding to protect your genitals if you fall.

No matter what activity you choose (for ideas, see “Pick your favorite,” below), avoid sporadic bouts of high-intensity activity. For one thing, the health benefits of exercise depend on the total amount of exercise rather than its intensity. But more importantly, higher-intensity activity raises your chances for muscle or joint injury and for sudden death as a result of heart rhythm disturbances, especially if you’re a “weekend warrior” or you haven’t had a medical check-up to clear you for intense exertion.

Pick your favorite

Dozens of activities “count” as aerobic exercise. Choose one — or even several — that you enjoy. You’ll be more likely to stick with exercise if you make the routine fun. Consider activities like these:

  • walking
  • hiking
  • raking leaves
  • gardening
  • aerobics
  • bicycling
  • dancing
  • swimming
  • jogging/running
  • golfing
  • tennis
  • racquetball
  • rowing
  • basketball
  • cross-country skiing

Before you start a session of aerobic exercise, include five to 10 minutes of light stretching and low-intensity movement to warm up; this is crucial to avoid injury. Also work in a cool-down period of equal length.

In addition to aerobic activities like walking, a well-rounded exercise program includes strength training, flexibility training (stretching), and balance exercises; each benefits your body in a different way. Strength training builds your muscles and bones and improves your body’s ratio of lean muscle mass to fat. Flexibility training keeps your muscles stretched and your joints limber, and may help prevent injury. Balance exercises ward off falls that can prompt injuries.

Keeping exercise safe

As Harvard’s Dr. Harvey Simon writes in his book The No Sweat Exercise Plan, “The greatest hazard of exercise is not doing it. Far more people are harmed by the lack of exercise than by its excess.” Although the benefits of regular physical activity far outweigh the risks, there are risks, which can range from minor inconveniences to life-threatening situations.

Perhaps the most common risks associated with exercise are muscle and joint problems. Strains, tears, or fractures can be caused by quick movements, such as lunging for a tennis ball. Stiffness, soreness of joints and muscles, and inflammation of tendons and ligaments may be brought on by training too hard or too often, using improper technique or poor equipment (such as worn-out exercise shoes), increasing your activity level too quickly, or not dropping back to a lower level of exercise after a period of inactivity.

By far the most frightening risk associated with exercise is sudden death. Sedentary people who abruptly embark upon vigorous exercise can increase their chances of dying from a heart attack or an arrhythmia, a change in the heart’s rhythm. But it’s important to keep this in perspective. The absolute risk of sudden death during any episode of exercise is minuscule: one in every 1.51 million exercise sessions. It’s equally important to remember that the risk of sudden death discussed here is associated with vigorous exercise. If you work out at a moderate level, your risk is negligible.

To make sure that your exercise routine is as safe and enjoyable as possible, take these simple precautions:

  • Talk to your doctor before beginning an exercise program, especially if you have a health problem. He or she can help you determine your limitations and develop a routine that’s appropriate for your fitness level.
  • Warm up and cool down properly.
  • Drink plenty of fluids.
  • Watch for signs of overheating — headache, dizziness, nausea, fainting, cramps, or palpitations — especially in hot, humid weather. If possible, schedule exercise sessions in the early morning or late evening, when temperatures tend to be lower.
  • Don’t exercise if you are ill. Resume exercising after you recover, but give yourself time to work back up to your usual level.
  • Let injuries heal. That doesn’t mean you need to give up exercise, though. For example, if you’ve sprained your ankle while jogging, try swimming or other activities that use your arms and keep you off your feet.
  • Dress in loose, comfortable clothing that’s appropriate for the weather.
  • Pay attention to your surroundings. If you walk or jog, for example, always face the traffic. If you bike, ride with the traffic; remember to wear a helmet and obey the rules of the road. Stick to well-lit streets. Consider bringing a cell phone.

Most importantly, listen to your body. Don’t overexert yourself. Cut back if you can’t finish an exercise session, can’t carry on a conversation while exercising, or feel faint or suffer aches and pains in your joints after exercising. Stop your activity and see a doctor right away if you experience burning, tightness, or a feeling of fullness in the chest or upper body; faintness or loss of consciousness; wheezing or shortness of breath that takes more than a few minutes to go away; or pain in the bones or joints.

Admittedly, highlighting the risks of exercise and suggesting various precautions might make you think that getting a daily dose of physical activity is risky business or an utter chore, but it’s not. It can actually be great fun. And it can help keep you — and your prostate — in top shape.

Originally published Oct. 1, 2008; last reviewed April 26, 2011.

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