The best time of day to exercise is a long-standing question, and now a new study suggests that it differs by sex. The team found that evening exercise was more effective for men than morning routines, while results for women varied, with different health outcomes improving with different exercise times.
There’s a huge body of scientific work investigating the effects that time of day might have on the effectiveness of exercise, and the results are quite mixed. While exercising just before bed seems to disrupt sleep, exercising in the morning, afternoon or early evening all seem to have their own pros and cons, and they can vary based on the type of exercise and the desired outcome – whether you’re looking to lose fat or build strength, for example.
For the new study, researchers at Skidmore College set out to investigate the effects of exercising at different times of day, with a particular focus on differences between men and women. And the results are intriguing, suggesting that for men evening exercise was the better choice, while for women it depended on what they wanted to get out of it.
“Here we show for the first time that for women, exercise during the morning reduces belly fat and blood pressure, whereas evening exercise in women increases upper body muscular strength, power, and endurance, and improves overall mood and nutritional satiety,” said Dr. Paul Arciero, principal investigator of the study. "We also show that for men, evening exercise lowers blood pressure, the risk of heart disease, and feelings of fatigue, and burns more fat, compared to morning exercise.”
The trial involved 27 women and 20 men undergoing a 12-week exercise program the team had previously developed called RISE. Participants were trained by coaches in 60-minute sessions four days a week, with each day focusing on resistance, sprint interval, stretching or endurance training. The only difference was whether they exercised between 6:30 and 8:30 am, or 6 and 8 pm, and all followed a careful meal plan.
All participants were aged between 25 and 55 years, were healthy, of normal weight and had highly active lifestyles. At the beginning of the trial they were assessed for their aerobic power, muscular endurance, flexibility, balance, upper and lower body strength and power, and jumping ability. Other measures of health, like blood pressure, arterial stiffness, respiratory exchange ratio, distribution and percentage of body fat, and blood biomarkers, were compared before and after the trial, as well as questionnaires about their mood and food satiety.
While the health and performance of all participants was seen to improve over the trial, regardless of the time of day they exercised, there did seem to be some differences in the degree of improvement in some measures. The study found that all women in the trial lowered their abdominal, hip and total body fat, as well as reduced blood pressure, but the morning exercise group showed greater improvements. Interestingly though, only men that exercised in the evening saw improvements to their cholesterol, blood pressure, respiratory exchange ratio and carbohydrate oxidation.
The team says that the study could help inform people about when in the day they should exercise, based on their sex or what they want to get out of it. However, it’s important to note that this is far from definitive, and regular exercise is important regardless of what time it takes place.
The research was published in the journal Frontiers in Physiology.
Source: Skidmore College via Scimex
