In addition to eating high-quality foods, physical activity can help you reach and maintain a healthy weight.
- Getting regular physical activity is one of the best things you can do for your health. It lowers the risk of heart disease, diabetes, stroke, high blood pressure, osteoporosis, and certain cancers, and it can also help control stress, improve sleep, boost mood, keep weight in check, and reduce the risk of falling and improve cognitive function in older adults.
- It doesn’t take marathon training to see real health gains. A 30-minute brisk walk on five days of the week is all most people need. Getting any amount of exercise is better than none.
- Being a “couch potato” may be harmful even for people who get regular exercise. [1-3]
Regular physical activity helps the body function better – it keeps heart disease, diabetes, and a host of other diseases at bay, and is a key component for losing weight.
- The precise amount of exercise needed to achieve or maintain a healthy weight varies based on a person’s diet and genes. The American College of Sports Medicine and the American Heart Association support the idea that “more activity increases the probability of success.” 
- How much exercise do you need? Physical activity guidelines— including strength training and flexibility training — explain how much you should be moving. Keep exercise safety in mind, too.
Physical activity can also help people maintain weight loss. 
- Among the nearly 3,700 men and women who are part of the National Weight Control Registry, a group that includes only people who lost more than 30 pounds and kept them off for at least a year, the average participant burns an average of about 400 calories per day in physical activity. That’s the equivalent of about 60 to 75 minutes of brisk walking each day, or 35 to 40 minutes of daily jogging.  But there’s quite a bit of variation from participant to participant—some require more physical activity to keep the weight off, some require less.
The Cost of Inactivity
Exercise and physical activity benefit the body, while a sedentary lifestyle does the opposite – increasing the chances of becoming overweight and developing a number of chronic diseases.
- Only about 30 percent of adult Americans report they get regular physical activity during their leisure time—and about 40 percent of Americans say they get no leisure-time physical activity at all. 
- The Nurses’ Health Study found a strong link between television watching and obesity.  Researchers followed more than 50,000 middle-aged women for six years, surveying their diet and activity habits. Findings showed that for every two hours the women spent watching television each day, they had a 23 percent higher risk of becoming obese and 14 percent higher risk of developing diabetes. It didn’t matter if the women were avid exercisers: The more television they watched, the more likely they were to gain weight or develop diabetes, regardless of how much leisure-time activity and walking they did. Long hours of sitting at work also increased the risk of obesity and diabetes.
- Researchers at Tokyo Medical University found an association between spending less time watching television and a lower risk of overweight and obesity in older adults, regardless of whether participants met physical activity guidelines. The study followed 1,806 participants between the ages of 65 and 74. Participants were put into one of four categories based on television viewing time. The less time spent watching television, the lower the participants’ risk of becoming overweight or obese. 
- Another study analyzed the global effect of inactivity on the increase of diseases. The researchers estimated that physical inactivity accounts for 6% of the burden of heart disease, 7% of type 2 diabetes, 10% of breast cancer, and 10% of colon cancer. Inactivity also causes 9% of premature mortality. These staggering statistics put the true dangers associated with inactivity into a global perspective. 
More recently, studies have found that people who spend more time each day watching television, sitting, or riding in cars have a greater chance of dying early than people who are more active. [3, 9, 10] Researchers speculate that sitting for many hours may change peoples’ metabolism in ways that promote obesity, heart disease, diabetes, and other chronic conditions. [1-3, 9, 11, 12] It is also possible that sitting is a marker for a broader sedentary lifestyle. Furthermore, staying active does not mitigate the harmful effects of sit time. As you plan your daily activity routine, remember that cutting down on “sit time” may be just as important as increasing “fit time.”
- Owen, N., et al., Too much sitting: the population health science of sedentary behavior. Exerc Sport Sci Rev, 2010. 38(3): p. 105-13.
- Hu, F.B., et al., Television watching and other sedentary behaviors in relation to risk of obesity and type 2 diabetes mellitus in women. JAMA, 2003. 289(14): p. 1785-91.
- Dunstan, D.W., et al., Television viewing time and mortality: the Australian Diabetes, Obesity and Lifestyle Study (AusDiab). Circulation, 2010. 121(3): p. 384-91.
- Haskell, W.L., et al., Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc, 2007. 39(8): p. 1423-34.
- Physical Activity Guidelines for Americans, U.S.D.o.H.a.H. Services, Editor. 2008
- Catenacci, V.A., et al., Physical activity patterns in the National Weight Control Registry. Obesity(Silver Spring), 2008. 16(1): p. 153-61.
- Statistics, N.C.f.H., Health, United States, 2009: With Chartbook on Trends in the Health of Americans. 2009: Hyattsville, MD.
- Inoue, S., et al., Television viewing time is associated with overweight/obesity among older adults, independent of meeting physical activity and health guidelines. J Epidemiol, 2012. 22(1): p. 50-6.
- Patel, A.V., et al., Leisure time spent sitting in relation to total mortality in a prospective cohort of US adults. Am J Epidemiol, 2010. 172(4): p. 419-29.
- van der Ploeg, H.P., Chey, T., Ding, D., Chau, J.Y., Stamatakis, E., Bauman, A.E. Standing time and all-cause mortality in a large cohort of Australian adults. Prev Med, 2014. 69C:187-191. doi: 10.1016/j.ypmed.2014.10.004.
- Schmid, D., Leitzmann, M.F. Television viewing and time spent sedentary in relation to cancer risk: a meta-analysis. J Natl Cancer Inst, 2014. 106(7). pii: dju098. doi: 10.1093/jnci/dju098.
- Chomistek, A.K., Manson, J.E., Stefanick, M.L., Lu, B., Sands-Lincoln, M., Going, S.B., Garcia, L., Allison, M.A., Sims, S.T., LaMonte, M.J., Johnson, K.C., Eaton, C.B. Relationship of sedentary behavior and physical activity to incident cardiovascular disease: results from the Women’s Health Initiative. Am Coll Cardiol, 2013. 61(23):2346-54. doi: 10.1016/j.jacc.2013.03.031