Sunday , February 18 2018

How much PA should adults get?

How do you communicate Physical Activity Guidelines? At the mid-July advisory committee meeting for the forthcoming 2018 Physical Activity Guidelines for Americans, this topic of interpreting and describing the 2008 Physical Activity Guidelines for Americans (key findings at bottom of page) arose. Aside from the issue that the notion of 3 days a week of aerobic exercise is still out there, decades after it ceased being the primary message, the committee observed that communicating a range of benefit has been problematic. What do YOU tell people? Do you advise adults to get 150 (moderate) minutes of aerobic activity a week?

The public looks for a minimum number, but the 2008 Guidelines indicate a range. Within the range, more is better. Even beyond the range, more aerobic exercise is generally better, with deleterious effects to some people under some circumstances, and no one recommending exercising all day every day for public health benefits.

The range of 150-300 weekly minutes of moderate aerobic activity has been reduced to a talking point of 150 minutes. Maybe that's understandable, as the main audience for the message of aerobic activity has implicitly been non-exercisers. For someone who hasn’t exercised in years, 150 minutes a week sounds out of reach, so you certainly wouldn’t want to advise 300, which would sound impossible. Health communications is a balancing of the science with what resonates with an audience. In that context, 300 is a number that prohibits action.

Why a range in the first place? The lengthy text of the Physical Activity Guidelines Advisory Committee Report, 2008, indicates that different outcomes require different protective levels of aerobic exercise. The science being uncovered for 2018 still seems to support this conclusion. So while we are very clear that being active prevents premature death from any cause, and heart disease, some cancers, Type 2 diabetes, complications from many chronic conditions, and more, pinpointing those varied numbers supported by research into one amount defies logic. You can argue that “all-cause mortality” (at least in a premature death sense) makes the most sense as an endpoint to avoid, and that’s a valid point. However, isn’t morbidity – illness and incapacity – the concern more Americans would have if given the choice?

Preventing morbidity and early mortality is a goal of health promotion -- to promote quality of life. CDC’s new Active People, Healthy Nation approach emphasizes moving people to the next level: From inactive to active, from active to more active. It’s reasonable to offer staged advice to people in different circumstances.

Generally, though: How can you reasonably translate science that doesn't pinpoint one amount into a recommendation that does? Offer your thoughts on our Facebook and Twitter pages.

-Pam Eidson, MEd, PAPHS
Executive Director
National Physical Activity Society

Note: The Advisory Committee’s role is to analyze the science and make a report to the Department of Health and Human Services. DHHS is then responsible for writing and communicating the recommendations to the public. The Physical Activity Guidelines Advisory Committee has held four public meetings, with video simulcast and recorded for future viewing. The Advisory Committee will conclude its work around the end of 2017. Guidelines are expected from DHHS in 2018. You can view recordings of the public meetings at

2008 Physical Activity Guidelines for Americans

The [2008] Physical Activity Guidelines for Americans describes the major research findings on the health benefits of physical activity:

  • Regular physical activity reduces the risk of many adverse health outcomes.
  • Some physical activity is better than none.
  • For most health outcomes, additional benefits occur as the amount of physical activity increases through higher intensity, greater frequency, and/or longer duration.
  • Most health benefits occur with at least 150 minutes (2 hours and 30 minutes) a week of moderate intensity physical activity, such as brisk walking. Additional benefits occur with more physical activity.
  • Both aerobic (endurance) and muscle-strengthening (resistance) physical activity are beneficial.
  • Health benefits occur for children and adolescents, young and middle-aged adults, older adults, and those in every studied racial and ethnic group.
  • The health benefits of physical activity occur for people with disabilities.
  • The benefits of physical activity far outweigh the possibility of adverse outcomes.

Key Guidelines for Adults

  • All adults should avoid inactivity. Some physical activity is better than none, and adults who participate in any amount of physical activity gain some health benefits.
  • For substantial health benefits, adults should do at least 150 minutes (2 hours and 30 minutes) a week of moderate-intensity, or 75 minutes (1 hour and 15 minutes) a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous intensity aerobic activity. Aerobic activity should be performed in episodes of at least 10 minutes, and preferably, it should be spread throughout the week.
  • For additional and more extensive health benefits, adults should increase their aerobic physical activity to 300 minutes (5 hours) a week of moderate intensity, or 150 minutes a week of vigorous intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity activity. Additional health benefits are gained by engaging in physical activity beyond this amount.
  • Adults should also do muscle-strengthening activities that are moderate or high intensity and involve all major muscle groups on 2 or more days a week, as these activities provide additional health benefits.





About Pam Eidson

Pam Eidson is executive director of the National Physical Activity Society.

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