Working out in the morning instead of the night can help women lose more fat around their waist as well as improve their blood pressure, according to a new study published in May in Frontiers in Physiology.
Researchers tested for health, strength and fitness in men and women, splitting them into two groups. One group exercised four times a week in the morning, between 6 a.m. and 8 a.m, and the other group worked out between 6:30 p.m. and 8:30 p.m. There were 65 participants, and half were women.
According to the Washington Post, the research was designed to reflect real-world demographics, said Paul Arciero, the director of the Human Nutrition, Performance & Metabolism Laboratory at Skidmore College, in Saratoga Springs, N.Y., and the study's lead author.
The workouts were the same at both times of day and consisted of either lifting weights, interval training for 35 minutes, yoga or Pilates, or running or other aerobic exercise. The study lasted 12 weeks, and all volunteers came back in generally better shape regardless of when they worked out.
— Skidmore College (@SkidmoreCollege) August 26, 2022
But there was a noticeable difference in women: Those who worked out in the morning saw their total body fat drop an average of 3 percent more than the evening exercisers. They also shed an average of 7 percent more abdominal fat, and their blood pressure lowered significantly more.
The women who worked out at night saw an increase in upper-body strength, nearly 7 percent more than the morning group.
"Based on our findings, women interested in reducing belly fat and blood pressure, while at the same time increasing leg muscle power should consider exercising in the morning. However, women interested in gaining upper body muscle strength, power and endurance, as well as improving overall mood state and food intake, evening exercise is the preferred choice," Arciero shared in a release. "Conversely, evening exercise is ideal for men interested in improving heart and metabolic health, as well as emotional wellbeing."
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As for men, working out in the evening was more effective at lowering their cholesterol levels. The evening group also burned 28 percent more fat overall than when they started the study. Still, strength and fitness remained relatively constant in both men's groups, no matter the time of day they exercised.
John Hawley, the head of the Exercise and Nutrition Research Program at the Australian Catholic University, told the Post that the study did not account for menstrual cycles or track if the people considered themselves morning or night people. Midday exercise was also not included.
Still, Arciero is planning follow-up studies to understand more, and to see if hormones or other genetic effects played a part in the findings.