When is the best time to exercise for men and women?

There has been much discussion and much controversy around when is the best time of day to exercise to maximize not just our overall physical health but also our physical performance.

I would probably say that any time of the day is the right time to exercise but there is some evidence that exercising at different times of the day can give a different result on our metabolism. We have certain times of the day when we are stronger we have certain times of the day when we have greater endurance. There are certain times of the day when different hormones are released.

I don't think we can make a general population-wide recommendation of here's what will happen if you exercise in the morning here's what will happen after you exercise in the evening. We have to understand that in this particular instance with exercise response and we have great scientific evidence that women and men respond differently to exercise at the beginning of this year. We published what we call an atlas of how different organs respond to exercise at different times of the day and what we did was a study in rodents in mice and we had these mice run on a treadmill for one hour either during the early active phase which would sort of be like their daytime or their early rest phase which would be like sleeping for them. We looked at how sugars and fats and proteins were metabolized when we had the mice perform the exercise in the morning.

There was a greater burning of different fuels in the tissues of the animals after the exercise period. It wasn't just the working muscle that broke down all the fuels. We found that the fat cells broke down fuels the liver broke down fuels um and many many organs contributed to the response of exercise when they perform the exercise during the early rest phase when they were supposed to be sleeping there was very little breakdown of the metabolism.

We recruited 30 women and 27 men and we had an early morning group of those that were exercising between six and eight a.m in the morning and then an evening group of those that were exercising between the hours of 6 30 and 8 30 pm. We chose those two time periods because they were most reflective of when people adults that were working that had families were most likely to be exercising. We had them exercise four days a week. I've developed this exercise paradigm called rise it consists of resistance exercise high intensity interval exercise stretching exercise and then endurance aerobic cardiovascular exercise. So those are the four different types of exercise we had these men and women doing over the 12-week study period and they were doing each form of those exercises one day a week. What we found was that the women that were exercising in the morning over the 12 weeks had significant reductions in their total body fat and more importantly in their abdominal fat region and that's a problematic area because we know it's associated with the highest risk for cardiovascular metabolic disease. In the evening women developed much greater strength in their upper body and then they also developed greater muscle function in their endurance capacity so they were able to do more repetitions. In the men what we found was that they generally improved regardless of what time they exercised either first thing in the morning or at the end of the day with a few exceptions.

The men that exercised in the evening had a greater reduction in their blood pressure when the men performed this high-intensity training in the afternoon they had a blood glucose-lowering effect that was great. The surprise was when the same men performed the exercise in the morning in this case they had a rise in their blood sugar levels we didn't expect that more world records have been broken when the competitions are performed in the afternoon or evenings and there's some evidence that people have greater power and they're stronger during the afternoon versus in the morning. There's some evidence that if you're not always familiar with or accustomed to exercising really hard training before you go to bed is very stressful for the body. It increases the heart rate you have more stress hormones on board you may not feel like you can sleep as well if you do a really hard training pass right before you go to bed.
Our study participants came in being very faithful and regular exercisers of one really major form we had runners we had cyclists we had powerlifters and so when they were asked to engage in these other forms that we were having them do over the 12 weeks. After the first two-three weeks there was like a light bulb that went off our bodies benefit from a multi-modal form of exercise as opposed to doing just one singular monolithic type of movement.

It's not an easy question to answer what time of day is best to exercise but I would take the take-home message as the best time to exercise. Find a time that fits your schedule and make sure that you incorporate that into your lifestyle. you have to always remind people that although there are certain time-specific benefits to exercising the bottom line comes down to when it is that you can do it and when you prefer to do it. For many people, there are chronological preferences to be a morning person others much prefer to do things in the evening so I would also encourage that as a consideration to just make sure that you're choosing the time of day that you're most likely to stick with it long term.