Physical Activity

The 2020 World Health Organization guidelines cover physical activity and sedentary behaviour for children, adolescents, adults, older adults, and sub-populations including pregnant and postpartum women and those living with chronic conditions or disabilities. ^[1] Sedentary physiology is considered a field separate and distinct from exercise physiology, because sedentary behaviours are associated with health outcomes that differ from those attributed to a lack of moderate-to-vigorous physical activity. ^[2]

Regular physical activity minimizes the physiological effects of an otherwise sedentary lifestyle and increases active life expectancy by limiting the development and progression of chronic disease and disabling conditions, though no amount can stop the biological aging process itself. ^[3] Physical activity is associated with improved cognition, and acute bouts of moderate-to-vigorous physical activity have transient benefits for cognition during the post-recovery period after exercise. ^[4]

A systematic umbrella review found that meeting the 2008 physical activity guidelines reduces mortality and cardiovascular disease risk to about 75% of the maximal benefit obtainable from physical activity, with beneficial associations beginning at very modest amounts (one-third of guidelines). ^[5] A systematic review reported strong evidence that higher versus lower physical activity levels reduce the risk of bladder, breast, colon, endometrial, esophageal adenocarcinoma, renal, and gastric cancers, with relative risk reductions of approximately 10% to 20%. ^[6] The 2018-guidelines umbrella review found moderate-to-strong evidence that physical activity benefits cognitive functioning across the lifespan and that greater amounts are associated with reduced risk of developing cognitive impairment, including Alzheimer's disease. ^[4] For adults with excess body weight, an American College of Sports Medicine consensus statement concluded that benefits for weight loss and prevention of weight gain are most prevalent when physical activity is progressed to at least 150 min/week of moderate intensity in a dose-response manner. ^[7]

Increasing moderate-to-vigorous physical activity to guideline amounts in the inactive population has the potential for an important and substantial positive impact on all-cause mortality, cardiovascular mortality, and incident cardiovascular disease. ^[5] Sub-optimal physical activity levels correlate with increased disease prevalence in aging populations, and physical activity slows aging rates as a foundational aspect of geroscience. ^[8]