Exercise has always been one of the major keys to health and longer lifespan. Conversely, lack of exercise has been linked to many diseases including cardiovascular disorders, type 2 diabetes, obesity, and osteoporosis. But what about cancer and exercise? Is there a link? Here are the latest updates on this topic.
Exercise and rest reduce cancer risk in women
This very recent report suggests that physical exercise among women only affords protection against cancer if complemented by a good night’s sleep. It seems that lack of sleep can cancel out the beneficial effects of exercise. Previous studies have linked poor sleep hygiene to breast cancer. In the current study, “findings suggest that sleep duration modifies the relationship between physical activity and all-site cancer risk among young and middle-aged women… Among women 65 or younger when surveyed and in the upper half of [physical activity energy expenditure] PAEE, sleeping less than seven hours a day increased overall cancer risk, negating much of the protective effects of physical activity on cancer risk for this group.”
Exercise cuts cancer death in men
Men who regularly engage in physical activity are less likely to die from cancer than those who don’t, These are the findings of a study conducted by Swedish researchers. The study looked at over 40,000 men aged 45 to 79 over a 7-year period. Those who walked or rode the bicycle for at least 30 minutes each day had a 5% lower risk of developing cancer and an increased survival rate of 33% compared to sedentary individuals. Those who did a longer exercise routine of 60 to 90 minutes had a 16% lower incidence of cancer. However, it is not only activities such as walking or cycling that can reduce cancer risk. According to the researchers, “we looked at more moderate exercise such as housework, undertaken over a longer period of time and found that this also reduced men’s chances of dying from the disease.”
Exercise and breast cancer
Most study results point to one thing: that physically active women have a lower risk of developing breast cancer compared to their sedentary counterparts. The risk reduction can vary between 20 to 80% and may also be closely linked to weight and body fat. The protective effects of exercise are especially evident among adult women (premenopausal and postmenopausal age) but exercise during adolescent years also makes a difference. Maximum protection is achieved through a lifetime of physical activity though not many people will probably qualify for this. However, increasing physical activity will show the greatest benefits when done just after the menopause. The protective mechanism may be explained as follows:
Physical activity may prevent tumor development by lowering hormone levels, particularly in premenopausal women, lowering levels of insulin and insulin-like growth factor I (IGF-I) improving immune response, and assisting with weight maintenance to avoid a high body mass and excess body fat.
Exercise and colorectal cancer
Many research studies have found that exercise can reduce the risk of developing colon cancer. Those who increase their physical activity in terms of frequency, intensity, and duration, or frequency can actually have a 30 to 40% risk reduction. Although some studies indicate that the protective effects of exercise increase with increasing intensity, it is not clear what the optimal levels of physical activities are. The current estimate is that about 30 to 60 minutes of moderate to vigorous physical exercise each day can render protection against colon cancer. Several mechanisms have been proposed to explain the anti-cancer effects of exercise.
Physical activity may protect against colon cancer and tumor development through its role in energy balance, hormone metabolism, insulin regulation, and by decreasing the time the colon is exposed to potential carcinogens. Physical activity has also been found to alter a number of inflammatory and immune factors, some of which may influence colon cancer risk.
Guidelines on physical activity for cancer survivors
Recently, the very first guidelines on physical activities for Americans have been issued by the US Department of Health and Human Services. Included in Chapter 7 are physical activity guidelines for people with chronic medical conditions. Here are the recommendations for cancer survivors:
With modern treatments, many people with cancer can either be cured or survive for many years, living long enough to be at risk of other chronic conditions, such as high blood pressure or type 2 diabetes. Some cancer survivors are at risk of recurrence of the original cancer. Some have experienced side effects of the cancer treatment.
Like other adults, cancer survivors should engage in regular physical activity for its preventive benefits. Physical activity in cancer survivors can reduce risk of new chronic diseases. Further, studies suggest physically active adults with breast or colon cancer are less like to die prematurely or have a recurrence of the cancer. Physical activity may also play a role in reducing adverse effects of cancer treatment.
Photo credit: stock.xchng