Study Reveals How Your Daily Rhythm Affects Aging and Wellness

A new study published in Medicine & Science in Sports and Exercise reveals that the timing and consistency of daily activity may significantly impact heart and lung health in older adults. The research found that earlier and more regular activity patterns were associated with better cardiorespiratory fitness and walking efficiency, key indicators of healthy aging. Although the findings are observational and do not prove causation, they open new possibilities for personalized health strategies based on an individual’s internal clock.

The circadian rhythm, or internal biological clock, regulates sleep-wake cycles and various physiological and metabolic processes. To explore its connection to physical fitness, researchers enrolled about 800 independent older adults with an average age of 76. Participants wore wrist devices that continuously tracked their daily movement over seven days. Their heart and lung health were then evaluated through cardiopulmonary exercise testing, providing a comprehensive assessment of cardiorespiratory function.

Key outcomes of the study showed that higher-amplitude activity and rest cycles-meaning greater activity during waking hours relative to rest periods-were linked to improved fitness and walking efficiency. Participants who reached peak activity earlier in the day and maintained consistent daily schedules also demonstrated better health outcomes. Activity was broadly defined to include all forms of movement, such as walking, gardening, shopping, or cleaning-not just formal exercise.

"While we've long known that being active supports healthy aging, this study reveals that when you're active may also matter," said Karyn Esser, Ph.D., senior author and chair of the UF College of Medicine's Department of Physiology and Aging. Esser emphasized that although her study suggests a link between earlier, consistent activity and better health, it doesn't prove that following such a schedule will improve health and fitness.

"Each of us has a chronotype-a biological tendency to be more alert in the morning or evening-and that variation may play a significant role in our health," Esser said.

Reference: Melissa L. Erickson, Terri L. Blackwell, Reagan E. Garcia, Theresa Mau, Peggy M. Cawthon, Steven R. Cummings, Samaneh Farsijani, Lauren M. Sparks, John Noone, Nancy W. Glynn, Anne B. Newman, Karyn A. Esser. Rest Activity Rhythms and their Association with Cardiorespiratory Fitness and Walking Energetics in Older Adults: Study of Muscle, Mobility and Aging. Medicine & Science in Sports & Exercise, 2025; DOI: 10.1249/MSS.0000000000003730