Consistent activity at same time, everyday related with improved fitness: Study

New Delhi: Timing and consistency of one's daily physical activity could be related with an improved cardiorespiratory fitness and walking efficiency -- two important aspects of healthy ageing, according to a study.

Circadian rhythms, or biological clocks, regulate a person's activities over a 24-hour period -- including sleep-wake cycles and wide-ranging physiological and metabolic functions.

"The circadian mechanisms that generate daily rhythms in our system are important for our well-being," senior author Karyn Esser, professor and chair at the University of Florida College of Medicine, US, said.

Eight hundred independent older adults, aged on average 76, wore wrist devices that continuously monitored activity for seven days. Their heart and lung health was assessed through cardiopulmonary exercise testing.

The findings, published in the journal Medicine and Science in Sports and Exercise, reveal that the participants with earlier and more consistent daily activity patterns had a better heart and lung fitness, compared with those having later or more irregular schedules.

"While we've long known that being active supports healthy ageing, this study reveals that when you're active may also matter," Esser said.

Cycles of intense physical activity and rest -- suggesting more movements during the active part of the day, compared to the resting part of the day -- were associated with better cardiorespiratory fitness and walking efficiency.

Further, a consistency in patterns of daily activity, such as peaking at the same time each day, was also associated with better outcomes.

"More rhythmic activity behaviour and earlier time of peak activity were associated with better cardiorespiratory fitness and walking energetics," the authors wrote.

They added that activity included movements throughout the day -- walking, gardening, cleaning or shopping -- and not just formal, structured exercise.

The findings provide evidence supporting the idea that rhythmic activity promotes healthy physiology. While the results are promising, more research is needed to determine whether adjusting activity timing can lead to health improvements and whether these findings extend to younger populations, Esser said.

Further investigations are warranted to determine if declines in rhythmicity of human behaviour are predictive of disease, the researchers said.