Run--and don't look over your shoulder, part 2.
D000328:Adult; D000367:Age Factors; D006321:Heart / Q000502:physiology; D006801:Humans; D008660:Metabolism; D008875:Middle Aged; D009142:Musculoskeletal Physiological Phenomena; D011674:Pulse; D012420:Running; D013178:Sports Medicine