There are advantages to working out at specific times during the day, such as first thing in the morning when you are fresh or during the afternoon, when you are at peak energy. If it will not disrupt your sleep, you can also work out before bedtime. However, working out at this time offers no metabolic benefits.
Carving time out of a busy day to work out can be challenging. You may choose to get up an hour or two early and get your workout out of the way first thing. But research has shown that you are not at your physical performance peak until later in the day. By late afternoon or early evening, your muscles are at their warmest and your lungs are working at their best. Thus, between 2 and 6 p.m. is the ideal time to work out.
Exercise and Metabolism
Whether it is cardio or strength training, exercise raises your metabolism. While exercising, you are burning more calories than you do when sitting still, for example. Depending on the intensity and duration of the exercise, your metabolism remains elevated for some time after you work out. This means that you continue to burn calories at a higher rate even after your workout is completed. The increase in postworkout calorie burning is not dependent on when your workout is done. Thus, working out before bed will not burn more calories or shed more body fat than working out at other times of day.
Sleeping and Cortisol
In general, exercise can help with sleeping problems. However, working out right before bedtime could make a sleeping problem worse. Exercise stimulates the release of a stress hormone called cortisol, which is similar to adrenaline in that it makes you alert. As a stress hormone, cortisol also causes biochemical reactions in your body that cause you to store body fat.
One exercise program that you can do right before bedtime is yoga. Basic Hatha yoga poses are not as intense as, for example, running and strength training. Yoga may help you relax before bedtime, as the stretching and deep breathing calm your body and mind.
A workout at any time of the day is better than no workout at all. There is no reason to worry if you have to move a workout back later in the evening to accommodate a long work day or an evening social event. However, try to complete your workout at least three hours before bedtime so that your body will have the chance to cool off. Do eat after your workout so your body will have the nutrients to recover from your workout while you sleep.
Marcus Schantz is an author and licensed attorney based in Chicago. He holds a Juris Doctor from the Northern Illinois University College of Law, as well as a Bachelor of Arts in anthropology and microbiology from the University of Texas at Austin.