Early morning or night best times to exercise

Ōtautahi - Recent research into how the time that people exercise affects the body has shown significant differences between morning and evening.

A new study used mice to carry out its research and while it has limitations, it provides a vital insight into how the timing of exercise can be used to improve people’s health.

These findings could help with exercise advice for people at risk from diseases such as diabetes and obesity.

It is well established that exercise improves health, and recent research has shown that exercise benefits the body in different ways, depending on the time of day.

However, scientists still do not know why the timing of exercise produces these different effects. To gain a better understanding, an international team of scientists from Sweden, Denmark, the US and Germany recently carried out the most comprehensive study to date of exercise performed at different times of the day.

Their research shows how the body produces different health-promoting signalling molecules in an organ-specific manner following exercise depending on the time of day.

These signals have a broad impact on health, influencing sleep, memory, exercise performance and metabolic homeostasis. Their findings were recently published in the journal Cell Metabolism.

A better understanding of how exercise affects the body at different times of day might help us to maximize the benefits of exercise for people at risk of diseases, such as obesity and type 2 diabetes.

Almost all cells regulate their biological processes over 24 hours, otherwise called a circadian rhythm. This means that the sensitivity of different tissues to the effects of exercise changes depending on the time of day.

Earlier research has confirmed that exercise timing according to circadian rhythm can optimise the health-promoting effects of exercise.

The team of international scientists wanted a more detailed understanding of this effect, so they carried out a range of experiments on mice that exercised either in the early morning or late evening.

Blood samples and different tissues, including brain, heart, muscle, liver and fat were collected and analysed by mass spectrometry. This allowed the scientists to detect hundreds of different metabolites and hormone signalling molecules in each tissue, and to monitor how they were changed by exercising at different times of the day.

The result is an atlas of exercise metabolism, which is a comprehensive map of exercise-induced signalling molecules present in different tissues following exercise at different times of day.

As this is the first comprehensive study that summarises time and exercise dependent metabolism over multiple tissues. It is of great value to generate and refine systemic models for metabolism and organ crosstalk, the researchers say.

New insights include a deeper understanding of how tissues communicate with each other, and how exercise can help to realign faulty circadian rhythms in specific tissues.

Faulty circadian clocks have been linked to increased risks of obesity and type 2 diabetes. Finally, the study identified new exercise-induced signalling molecules in multiple tissues, which need further investigation to understand how they can individually or collectively influence health.

Not only does the research show how different tissues respond to exercise at different times of the day, but it also proposes how the responses are connected to induce an orchestrated adaptation that controls systemic energy homeostasis.

The study is the result of a collaboration between the University of Copenhagen in Denmark, Karolinska Institute in Sweden, Texas A&M University, the University of California-Irvine, and Helmholtz Munich.