A recent study by researchers at the University of Florida Health reveals that not only the amount of daily physical activity but also its timing and regularity are linked to better fitness in older adults. This groundbreaking research shows that older adults who engage in physical activity earlier in the day and maintain consistent daily routines tend to have improved cardiorespiratory fitness and more efficient walking patterns — two crucial markers of healthy aging.
The study, published in Medicine & Science in Sports & Exercise, involved about 800 independent older adults with an average age of 76. Participants wore wrist-worn activity monitors for seven consecutive days to track their movement patterns. Their heart and lung health were then assessed through cardiopulmonary exercise testing.
Key findings from the study include:
Older adults who displayed higher-amplitude activity rhythms — meaning more intense activity during their active periods compared to rest periods — demonstrated better heart and lung fitness.
Those whose peak activity occurred earlier in the day showed superior cardiorespiratory function and walking efficiency.
Greater consistency in daily activity timing, such as performing peak activity at roughly the same time each day, correlated with improved physical health outcomes.
Importantly, the study defines activity broadly, encompassing all daily movements like walking, gardening, and household chores, not just formal exercise routines.
The research highlights the role of circadian rhythms — the body’s natural biological clock that regulates sleep-wake cycles and many physiological functions such as hormone release and core body temperature. Disruptions to these rhythms, for example from shift work or jet lag, are known to negatively impact health.
Senior author Dr. Karyn Esser, professor and chair of the Department of Physiology and Aging at UF College of Medicine, emphasized that while the study demonstrates a strong association, it does not prove that changing the timing of activity alone will improve fitness. “The circadian mechanisms that generate daily rhythms are important for our well-being,” she said. “More research is needed to confirm whether adjusting activity timing can directly lead to better health and if these findings apply to younger populations.”
This research opens new avenues for personalized medicine, suggesting that tailoring physical activity and treatment schedules according to individual biological clocks — known as chronotypes — could optimize health outcomes. People naturally vary as “morning larks” or “night owls,” and respecting these individual differences might become an important factor in future health and wellness strategies.
Dr. Esser herself identifies as a morning person, or “lark,” but acknowledges that many colleagues are “owls” who prefer evenings.
This study adds to the growing evidence that aligning daily behaviors with our internal clocks can promote healthier aging and improved physical function.
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