For men, an evening workout offered the most benefit. For women, the answer varied, depending on whether the goal was to burn fat or build muscle.
There is no wrong time to exercise, but there may be some times that are more right than others.
The best time of day to exercise can depend on your gender and even whether you want to burn fat or get stronger, according to a helpful new study of men, women and exercise timing.
It found that, for women, morning workouts zapped abdominal fat and improved blood pressure better than late-day training. For men, evening exercise led to greater fat burning and better blood pressure control. Evening exercise also amplified the benefits of strength training, but more so for women.
Studies of exercise timing are part of the burgeoning science of chronobiology, which focuses on how our internal clocks affect almost every aspect of our physiology.
Human bodies, like those of other mammals, plants, reptiles and insects, operate on an innate 24-hour circadian rhythm, with a master clock system in our brains sending and receiving biochemical signals that coordinate with molecular clocks inside our cells to direct a boggling symphony of biological processes.
This rhythm, in turn, responds to signals from the outside world, especially daylight and darkness, but also when we eat, sleep and exercise.
Recent studies in mice allowed large groups of rodents to run on exercise wheels at varying times of day. The studies showed that the animals’ heart rates, fat burning, gene expression and body weights change substantially, depending on when they exercise — even if the exercise itself is the same.