Exercise and Cancer

Exercise is known to help prevent cancer and other deadly diseases such as heart disease. Cardiovascular exercise (anything that gets your heart rate up during a sustained period of time) is the best kind to get. We are not exactly sure why exercise reduces cancer risk, but we know that it does.

In women, the reduced body fat that results from exercise reduces the amount of estrogen in the blood, so this would decrease the risk of certain cancers. However, exercise and leaner bodies in men also lower cancer risk, so it is probably not just the lower estrogen levels that decrease the risk. One reason that exercise might help prevent cancer is that tumors need energy to grow. If you exercise, you are using up energy that would otherwise become fat. Cancer cells will find it more difficult to thrive without an adequate energy supply. This is why obese people have a much greater risk for cancer.

A 14 year Harvard School of Public Health study in which 125,000 people participated found that exercise decreases the risk of developing Parkinson's disease by 50 percent in men who were exercising at the beginning of the study. Men who said that they had exercised vigorously when they were younger had a 60 percent reduction in risk. For women, there was no reduction in risk for those that were exercising at the beginning of the study, but there was a 50 percent reduction for those that had exercised significantly during their younger years, although the relationship was not statistically significant. Mouse studies have shown that the risk or severity of Alzheimer's disease can be reduced with exercise and play.

Some of this association between exercise and lower risk is probably due to the fact that people that exercise lead healthier lifestyles on average; they smoke less, have less body fat, and probably eat more fruits and vegetables.

Lactic acid, which is produced in the muscles after strenuous anaerobic exercise, acts as an antioxidant, scavenging free radicals from your body. This is probably another reason why exercise is known to be good for preventing cancer and other degenerative diseases. The bottom line is that studies have shown that exercise lowers cancer risk, as well as the risk of heart disease.

Chapter 15 – Exercise

As mentioned in Section II of the book, exercise helps prevent cancer. Although we don't know exactly how it does so, the evidence shows that it does. Exercise should be part of any cancer prevention program. As we have mentioned before, most things that prevent cancer also lower the risk for heart disease, and exercise is no different.

There are many different forms of exercise that, besides being healthy, can be fun. Many people think that exercise means running 5 miles, and although this is a form of exercise that would probably keep you very fit and lean, you do not have to go to these lengths. For those of you that aren't used to exercising, we have a few simple suggestions:

• Walking – If you currently get no exercise at all, you can start with a half-hour walk every day. Make sure you go as fast as you can (while still walking) and that your heart rate goes up. No investment is required for this activity. If you have chest pain or don't feel well, stop and go see your doctor.
• Jogging – If you find that walking doesn't really elevate your heart rate that much, you might be ready for jogging. Jogging burns off more calories and will keep you leaner.
• Biking – Whether you just want to ride around your neighborhood, go for 50 miles on the highway, climb a mountain all day, or just use a stationary bike, biking can be a fun and super healthy exercise.
• Swimming – For those of you that don't have much time to exercise but want to get a full-body workout, you might want to start swimming. Swimming is great because it is an aerobic exercise in which you use every muscle in the body.
• Tennis – Most people in the US live relatively close to public tennis courts, so you don't even have to invest too much. This is a fun sport in which you can also socialize. Other racket sports are as good, such as racquetball and squash.
• Health Club – If you can afford it, joining a health club is the easiest way to get a wide variety of exercise. You can walk or jog on treadmills, use stationary bikes, lift weights, and take aerobics and other classes.

There are many more sports and other activities in which people can engage, but we limited ourselves to listing some of those that are simpler and easier-to-accomplish. Whatever you decide to do, make sure that you do it at least four times a week and that you improve your performance over time. If you are walking, try walking faster. If you are running a certain distance try to lower your time, or if you are running a certain amount of time try to run farther. If you are just going to walk, then make sure you do it practically every day.

Most people in the US spend a significant part of their free time watching TV. If you think about it, TV does not add that much value to your life. Skip a show or two each day and go get some exercise. You will feel better a couple of weeks after you start. You should check with your doctor before starting an exercise program.