Some studies suggest that focused exercise is healthier than regular daily activity alone. Although the U.S. Surgeon General recommends regular daily exercise, many adults do not exercise. In this study, Brach and colleagues used data from the Health, Aging and Body Composition (Health ABC) study to determine health benefits associated with three different levels of activity: no activity, daily active living, and regular exercise.

Participants in the Health ABC study included 3,075 men and women 70 to 79 years of age. The inactive, lifestyle active, and exercise groups were defined on the basis of participants' weekly physical activity and kilocalorie expenditures. These numbers then were correlated with determinants of physical function, which included endurance, strength, and lower extremity function, as measured by the Established Populations for the Epidemiologic Studies of the Elderly (EPESE) and the Health ABC battery.

Of this group, 24.4 percent were exercisers, 52.2 percent were lifestyle active, and 23.4 percent were inactive. The total level of physical activity reported was similar in the two active groups and was significantly greater than the activity level reported by the inactive group. Progressive trends toward increasing walking endurance were noted along the continuum from the inactive to the lifestyle active and exercise groups. The lifestyle active and exercise groups had similar leg strength, which was greater than that in the inactive group. Participants in the inactive group were most likely to score less than 10 on the EPESE battery, which indicated lower extremity functional limitation. Progressive trends toward greater function scores were evident with EPESE and Health ABC batteries, with higher scores correlating with greater activity. Using EPESE scores, the lifestyle active group and exercisers had similar proportions of functionally limited participants, but using scores from the more stringent Health ABC battery alone, exercisers had better functional capacity than the lifestyle active group.

The two active groups had better function than the inactive group, but the exercisers demonstrated greater functional capacity or reserve than the lifestyle active group. The main difference is that being physically active in general protects against functional limitation, whereas sustained, planned exercise activity improves functional capacity. Regular exercise is probably the most beneficial way of preserving function and capacity, but any sort of activity is better than no activity at all.