Evaluating Exercise and Health is Harder Than You Might Think
Studies of exercise show that moderate regular exercise produces meaningful benefits in health and longevity. Life expectancy is improved by five years, give or take, incidence of age-related disease is lower, and lifetime medical costs are lower. The challenge here when trying to put numbers to the benefits of exercise is that day to day activity for many people rises to the level of moderate regular exercise. Quantifying this activity can be hard, however, and may greatly increase the cost of a study. Even in the old, activities that wouldn't ordinarily be counted as deliberate exercise have an impact on health. This has only become very clear in recent years, with the emergence of small, widely available accelerometers that study participants can wear throughout the day.
Here, for example, is a study to show that non-exercise activity does is correlated with health and longevity, as you might expect:
Sedentary time is increasing in all societies and results in limited non-exercise physical activity (NEPA) of daily life. The importance of low NEPA for cardiovascular health and longevity is limited, especially in elderly. [This study examines] the association between NEPA and cardiovascular health at baseline as well as the risk of a first cardiovascular disease (CVD) event and total mortality after 12.5 years. Every third 60-year-old man and woman in Stockholm County was invited to a health screening study; 4232 individuals participated (78% response rate). At baseline, NEPA and exercise habits were assessed from a self-administrated questionnaire and cardiovascular health was established through physical examinations and laboratory tests. The participants were followed for an average of 12.5 years for the assessment of CVD events and mortality.At baseline, high NEPA was, regardless of regular exercise and compared with low NEPA, associated with more preferable waist circumference, high-density lipoprotein cholesterol and triglycerides in both sexes and with lower insulin, glucose and fibrinogen levels in men. Moreover, the occurrence of the metabolic syndrome was significantly lower in those with higher NEPA levels in non-exercising and regularly exercising individuals. Furthermore, reporting a high NEPA level, compared with low, was associated with a lower risk of a first CVD event (hazard ratio of 0.73) and lower all-cause mortality (hazard ratio of 0.70). A generally active daily life was, regardless of exercising regularly or not, associated with cardiovascular health and longevity in older adults.