by Mila McManus, MD
It seems to be the norm now to argue over many topics as though there are only two solutions, a right way and a wrong way. But in reality, the answer is not dichotomous. Rather, there are gray areas in between, a number of good options available, and most often the need for individuals to choose what works best for them. Much like we say there is not one diet that is right for all people, the same is true with exercise. The best time of day for exercise is the time of day you will do it. The best exercise is the one you will do.
AM Prose: Some research suggests that exercising in the morning in a fasted state may be most helpful in weight control and training adaptations. It can also be logistically suitable for early risers. Those who train in the morning tend to have better training adherence and expend more energy overall throughout the day. Morning exercise is associated with better weight control, and better skeletal muscle adaptations over time compared to exercise performed later in the day, according to Dr. Normand Boulé from the University of Alberta[1].
PM Prose: Alternatively, Dr. Jenna Gillen from the University of Toronto[2], who has debated Boulé, points out that mild to moderate intensity exercising done soon after meals typically results in lower glucose spikes after meals in people with diabetes. Her argument is supported by at least one recent meta-analysis where post-meal walking was best for improving blood sugar in those with prediabetes and type 2 diabetes. The Look AHEAD Trial of over 2400 adults with type 2 diabetes found that some of the participants, after a year of making afternoon exercise part of their lifestyle, experienced a complete remission of diabetes. And for night owls, afternoon or evening exercise may just be more practical.
AM/PM Prose: It may be beneficial for some people to split exercise into two timeframes. Exercising some in the morning and some later in the day or early evening can offer several benefits. Exercise following the largest meals of the day aids in balancing blood sugar throughout the day. For those who sit for long periods, exercising twice a day helps to reduce stiffness and increase flexibility, increase focus and alertness, and reduces overall anxiety and stress levels.
Exercise is essential for physical and mental health. It is highly protective against disease and aging. It even helps prevent cancer and recurrence of cancer! Pick your form of exercise, pick your time, and get it done. Studies show that even as little as 5 minutes is helpful!
[1] Boulé, Normand G.; Rees, Jordan L.. Interaction of exercise and meal timing on blood glucose concentrations. Current Opinion in Clinical Nutrition and Metabolic Care 26(4):p 353-357, July 2023. | DOI: 10.1097/MCO.0000000000000936
[1]Jenna B. Gillen, Stephanie Estafanos, and Alexa Govette. 2021. Exercise-nutrient interactions for improved postprandial glycemic control and insulin sensitivity. Applied Physiology, Nutrition, and Metabolism. 46(8): 856-865. https://doi.org/10.1139/apnm-2021-0168