Kats D, Evenson KR, Zeng D, Avery CL, Palta P, Kritchevsky SB, Heiss G. Leisure-time physical activity volume, intensity, and duration from mid- to late-life in U.S. subpopulations by race and sex. The Atherosclerosis Risk In Communities (ARIC) Study. Aging (Albany NY). 2020 03 13; 12(5):4592-4602.