By Ken Smith

The U.S. Office of Disease Prevention and Health Promotion on November 12 released the second edition of Physical Activity Guidelines for Americans. These are the first new guidelines issued by the government since the initial release of activity recommendations in 2008. They are the culmination of a nearly two year process in which an advisory team, co-chaired by Center on Longevity Faculty Affiliate Dr. Abby King, examined a host of new research around physical activity and its connection to overall health. They address a number of new areas key to long-term wellbeing that include contributions from Stanford Center on Longevity researchers and faculty affiliates. Particularly notable updates include:

First-ever recommendations on limiting sedentary behavior
A growing body of science recognizes that extended periods of sitting presents health risks different than simply lack of exercise. In 2010, the Center on Longevity convened many of the world’s leading experts on this topic. Their conclusion, echoed in the new guidelines, was that there is a strong relationship between time in sedentary behavior and the risk of all-cause mortality and cardiovascular disease in adults. While the guidelines recognize the substantial risk in sedentary behavior, the underlying science has not yet found a way to quantify “how much is too much?” and the guideline make a general recommendation to limit sedentary time, rather than imposing a specific number of minutes or hours. To learn more about this topic, visit the Center’s 2018 Update on Sedentary Behavior Science.

Recognition of the contribution of physical activity to brain health
The Guidelines now recommend physical activity not only to strengthen the body, but also to maintain a healthy brain across the life span. For children, the guidelines outline the relationship between activity and brain maturation and development, as well as academic achievement. For older adults, activity confers a reduction in the risk of dementia and cognitive impairment in both the short and long term. At all ages, activity is related to improved cognition, reduced anxiety, and better sleep quality.

Elimination of the “10 minute rule”
The previous Guidelines communicated that activity needed to occur in bouts of at least ten minutes to have health benefits. The last decade of research has changed that thinking. While the guidelines still recommend at least 150 minutes/week of moderate to vigorous activity, they now point out that even small amounts of exercise (climbing the stairs, for example) “count” towards that goal. They also point out the even if the 150 minute guideline cannot be met, some activity is still better than none. This change in viewpoint is significant – people should not be discouraged if they are unable to meet guidelines, but rather understand that whatever they can do to increase activity has a positive effect. For an increasingly sedentary population, this is an important message that has been consistently stressed by the Center on Longevity following its 2014-2016 collaboration with the President’s Council on Fitness, Sports, and Nutrition on messaging to older Americans.

Guidelines for older adults
The Committee’s new message to older adults is on-point. First, the guidelines do not change with age for those who can maintain them. This is a subtle, but important shift – people should not ramp down activity simply because they reach a certain age. The recommendations do, however, recognize that adults with chronic conditions need to adjust their level of activity according to their health status. In short, level of activity is an issue of health, not age. Here again, the recommendation that even a small amount of activity is worthwhile applies. The Guidelines also recommend that older adults (as well as younger ones) should include muscle-strengthening activities and balance training, as well as aerobic training. This follows the growing body of evidence that resistance training at older ages is effective in battling conditions such as sarcopenia, osteoarthritis, and frailty. For people already experiencing these conditions, there is possibility for improvement, but workout plans should be coordinated with their healthcare professional to avoid injury.

The new government activity guidelines are notable not only for their changes, but for the thorough treatment of the science of physical activity for all Americans. It is perhaps the best overview of the topic available today for a non-academic audience and worth a look.

For more on Dr. King’s thoughts on the guidelines and the process of developing them, visit this article in SCOPE from Stanford Medicine.

Ken Smith, is Director of the Mobility Division and a Senior Research Scholar at the Stanford Center on Longevity.