It’s the perennial dilemma for fitness enthusiasts: is it better to hit the gym at first light or wait until the evening?
Engaging in any form of physical activity ensures our bodies have the best opportunity to fight disease so we can live a long life. However, it is not just a matter of how much we move, but when we do it.
In clinical settings, exercise physiologists develop and prescribe different plans to suit patients’ circumstances. However, lack of evidence has long meant that the timing of exercise has not been part of the prescription. This may be about to change.
Every day, our biological clocks tick to the beat of our circadian rhythms, which play a critical role in regulating physiological functions such as releasing hormones and controlling body temperature, sleep-wake cycles, and metabolism.
And now, new research suggests that exercising in the evening can have a greater effect on insulin sensitivity, which plays a key role in regulating glucose from the bloodstream to our cells, where it is used to create energy.
Most healthy individuals can compensate for reduced insulin sensitivity by producing more of this hormone as it is required. However, those with obesity and type-2 diabetes cannot produce enough of this chemical to compensate for changes in insulin sensitivity/resistance, which puts them at risk of complications such as kidney disease and heart failure.
Experts say insulin resistance can be altered through exercise, given that physical activity, like nutrition, is a powerful regulator of our biological clocks.
And recent clinical trials involving adults with type-2 diabetes or cardiovascular disease have shown that exercising in the evening results in greater glucose control and blood-pressure regulation than undertaking physical activity earlier in the day.
In detail, researchers from the University of Sydney conducted a study, published in Diabetes Care, involving almost 30,000 participants. They found that those with obesity who carried out regular moderate-to-vigorous physical activity at any time significantly reduced the risk of developing complications such as heart failure, stroke, and kidney failure, as well as premature death.
Using data from wrist trackers and machine learning, the experts were able to capture participants’ activity patterns and classify them according to the time of the day during which they did the majority of their physical activity.
The findings revealed that those who did the most physical activity from 6pm to midnight experienced the lowest rates of mortality with a 61% risk reduction, as well as a 36% reduced risk of cardiovascular disease.
Participants also had lower blood pressure and improved glucose regulation associated with physical activity in the evening. These findings were even more pronounced in the subset of participants who, in addition to obesity, had type-2 diabetes.
Another important finding was that exercising more than once throughout the day, or spaced out during specific time windows, may be more beneficial than accumulating all your physical activity in one block.
This is supported by physiological evidence showing that repeated muscle contractions throughout the day may facilitate better blood glucose control, which ultimately reduces the risk of cardiovascular disease, organ failure, and other associated complications.
Nevertheless, further research is required into so-called “chrono-exercise” to see how crucial it could be in managing obesity-related conditions. And, ultimately, the researchers emphasise that physical activity undertaken at any time is beneficial for health, as opposed to no activity at all.
This article was written by researchers Angelo Sabag, Matthew Ahmadi and Emmanuel Stamatakis from the University of Sydney for 360info.