Timing and consistency of an individual's daily activity may be associated with improved cardiorespiratory fitness and walking efficiency — two key indicators of healthy aging, researchers say. They found that older adults with earlier and more consistent daily activity patterns had better heart and lung fitness compared with those with later or more irregular schedules.

“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, PhD, senior author and professor and chair of the UF College of Medicine’s Department of Physiology and Aging.

“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. “We’re moving toward a future where understanding and respecting our individual rhythms can help guide medical care and daily living.”

Researchers enrolled about 800 independent older adults with an average age of 76. Participants wore wrist devices that continuously monitored activity for seven days. They then underwent cardiopulmonary exercise testing to obtain a comprehensive assessment of their heart and lung health.

Key findings include:

• Higher-amplitude activity and rest cycles — this reflects greater activity during the active part of the day relative to the rest period — were associated with better cardiorespiratory fitness and walking efficiency.
• Earlier daily peak activity — defined as the time of day when individuals were most active — was linked to improved cardiorespiratory fitness and walking efficiency.
• Greater consistency in daily activity patterns, such as having the peak activity occur at the same time each day, was also associated with better outcomes.

Activity included all daily movement — walking, gardening, cleaning or shopping — not just formal exercise.

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 necessarily improve health and fitness.

Still, the findings open intriguing possibilities for personalized medicine, she said. The body’s internal clock helps align physiological functions, such as hormone release, blood pressure and core temperature, to the natural cycle of day and night. Because circadian rhythms vary from person to person, future health strategies could include tailoring activity and treatment schedules to an individual’s internal clock.

To download the full study, published in Medicine & Science in Sports & Exercise, click here