Many people focus on weight loss as a means to improve appearance, but excess body fat (especially in the absence of regular exercise) also increases the risk and/or progression of many diseases such as cardiovascular disease, Type 2 diabetes and hypertension. Further, excess body weight can impair mobility through a combination of factors that produce unwanted limitations on muscle and joint movement such as poor alignment of joints and increases in circulating substances released from the fat tissue that increase the risk for osteoarthritis. Because health and mobility are critical to maintaining a high quality of life as people age, making an effort to keep a healthy body weight throughout the lifespan is important.

It goes without saying that a primary and essential intervention for managing weight is to engage in physical activity. Significant debate, however, centers around how often and how much physical activity is actually necessary to reach weight management goals. Recently, it has become clear throughout the fields of exercise physiology, aging, and mobility that weekly requirements for physical activity associated with healthy weight targets need to be adjusted upwards from existing guidelines and that there is likely a “dose effect” where more is indeed better when it comes to weight management.

The American College of Sports Medicine (ACSM) recently completed a comprehensive examination of research from 1999 to the current year on the connection between necessary amounts of physical activity (PA) and the goals of weight management. Based on the large body of research reviewed, ACSM released a February, 2009, Position Paper

The Prevention of Weight Gain

The most effective way to avoid the health and mobility problems associated with being overweight is obviously to maintain a healthy weight and stave off the creeping weight gain that often accompanies advancing age. Studies have proposed defining weight maintenance as “<3% change in body weight with >5% change in body weight considered significant”. While the amount of physical activity needed to maintain weight will likely vary across time for each individual, the 2009 ACSM position paper recommends moderate intensity physical activity of 150 minutes per week to prevent significant weight gain and reduce chronic disease factors associated with inactivity and being overweight.

The Promotion of Modest Weight Loss

The promotion of weight loss is becoming increasingly important every year as the number of overweight and obese individuals has climbed to a current high of 66% of the adult population in the United States. Studies show that improvements in health and mobility and the reduction of chronic disease factors can be obtained with as little as 2-3% of total weight loss at least in the short-term. The ACSM recommends that 150 minutes of moderate intensity PA per week is also sufficient in most individuals to result in this type of modest reduction in weight.

The Promotion of Greater Weight Loss and/or Prevention of Weight Regain

The maintenance of a new weight after pounds have been lost is the most difficult and elusive achievement for most adults. Prevention of weight regain is highly improbable without physical activity. The ACSM recognizes that when it comes to weight loss and the prevention of weight regain, there is likely a dose effect, where the more PA per week an individual engages in, the more it will impact weight management in these two categories. After reviewing all the research, the ACSM has updated its position to recommend 250-300 minutes of moderate intensity, weekly PA for more significant weight loss and preventing weight from being regained.

The current focus on PA and weight related goals, while significant, should not eclipse the fact that PA is essential to a healthy and active lifestyle irrespective of weight management factors. On this topic of general health benefits from PA, the ACSM continues to recommend previously announced target amounts of aerobic and resistance exercise that will provide increased endurance, strength, flexibility, balance, and other health related benefits in adults and older Americans of all weights and body types. (link to article on Stanford web).

For more information on the ACSM position stand and recommendations go to:

http://www.acsm.org/AM/Template.cfm?Section=Home_Page&TEMPLATE=/CM/HTMLD...