You should exercise at night: here’s why

Moonlit workouts in Dubai have the science to back them up

Driving out of the airport in the middle of the night, there inevitably will be a cluster of hotels, all with one room lit up: the gym. At any hour of the night, you can see business travellers pounding the treadmill, or hitting the weights in efforts to stave off inevitable jetlag. And though there is a glut of research to suggest that working out in the morning is preferable, new studies are providing a compelling counter-story.

One of these night workout junkies used to be Christina Guastella. As both an exercise lover and a frequent flyer, more often than not she found herself in the gym at all hours of the night.

“I’d always have to make time wherever I was off – I used to get off the plane and go and do some training just to feel alive, because I knew the time zones would throw me off,” she explains.

Now cofounder of NRG Fitness, a gym in Dubai, her hours are a little more predictable. But she holds steadfast to ideas of which types of exercise suit certain hours.

“In the early mornings I’ll go for a run or go to a spinning class, but I much prefer strength training in the evenings – I’m less stiff, and can concentrate on technique.”

Weight training is more effective in the evening as your anaerobic levels are higher and your body will produce more testosterone. It’s why you see a lot more guys in the gym in the evening

Sharon McConnell, Trainer, NRG Fitness in Dubai

“If you were to do a high cardio class early in the morning, it helps you get to the office and gives you a buzz,” she adds. “But if you get that buzz in the evening, your state of arousal is naturally higher, so the circulation of stress hormones also become higher after exercise. And if you attach that to evening, it may well disrupt your sleep.”

This is not merely personal preference. There is a raft of research that suggests effectiveness of exercise is directly impacted by our circadian rhythms.

Sixteen males were tracked by the University of Southern Mississippi, who asked them to workout for 10 weeks, four times a week; each workout consisting of 45 minutes on weights, and 45 of cardio. The only difference in their training was that half the group worked out before 10am, and the other half worked out after 6pm.

Results showed that the evening group saw a 3 per cent increase in lean muscle mass and about a 4 per cent decrease in bodyfat, while the group that trained in the morning had little to no increase in lean muscle mass, and no decrease in bodyfat.

Christina Guastella
For Christina Guastella, weight training is most effective in the evening

The greater decrease in bodyfat in the evening, it was posited, could’ve been due to increasing the subjects’ metabolism at a time when they would naturally drop off. A decreased metabolism during the evening has no single cause, but scientists have attributed it to a mixture of changes, from a lower body temperature (which prepares the body for sleep), a reduction in muscular activity, and our circadian rhythms, which are based on a 24-hour sunlight cycle.

Exercise scientists at the University of South Carolina in Columbia also found that men who exercised up to half an hour before sleep found no difference in ability to sleep, only a raised body temperature.

Another study by the University of Chicago profiled 40 healthy men under five different conditions of exercise. It was found that subjects who exercised at night had much larger drops in glucose levels, as well as large increases in the levels of two hormones important for energy metabolism, cortisol and thyrotropin. Exercise at other times of day had much smaller effects on these hormones.

"The effects of exercise we observed may explain how some times of day could be better than others for regular exercise or athletic performance, as we might expect from anectdotally reported variations in peak athletic performance," said Orfeu Buxton, PhD, a post-doctoral fellow in endocrinology at the University of Chicago at the time.

Subjects who exercised at night had much larger drops in glucose levels, as well as large increases in the levels of two hormones important for energy metabolism

University of Chicago study

"We found strong evidence for substantial changes in glucose metabolism and an array of hormonal responses to one-hour, high-intensity exercise, dependent on the timing of the exercise. Circadian rhythms, generated by our 24-hour internal clock, appear to play an important role in the complex response to exercise."

“Weight training is more effective in the evening as your anaerobic levels are higher and your body will produce more testosterone,” adds Sharon McConnell, also a trainer at NRG Fitness in Dubai. “It’s why you see a lot more guys in the gym in the evening than you would first thing in the morning."

"Studies have found that exercising resistance/weight training in the evening helps with a better night sleep, along with cardiovascular training in the morning clears stress hormones to help with your day ahead and can assist with a better sleeping pattern also.”

Beyond physical benefits, there are social uses to working out in the evening too. Says Guastella: [It’s] best for those who like the social aspect of training – as early morning risers tend to be more focused on getting in their workout early (while still waking up) and get the training done and over with before rushing out to work.”

The benefits of an evening workout span from greater strength and endurance which can be transferred to more effective weight training, less chance of injury as opposed to a morning workout when muscles are ‘cold’, a higher chance of sociability and perhaps, a greater chance of losing bodyfat.

Alarming for the virtuous morning exercisers among us perhaps, but for night owls – a cause for celebration.