Best time of day to exercise for fast results

Fasted cardio, first thing? Lunchtime squats? Post-work spin? The internet is awash with conflicting advice on the best time to optimise your training. In part, that’s because a range of factors determine your body’s prime time for fat loss: your genes, body type, circadian rhythm, and so on.

That’s all well and good but, after a summer of doing nothing, there's a good chance you don't want to wait months on end to see some results. Gratifyingly, if you’re aiming for fast muscle gains, like a bigger bum, rather than weight loss, the science is irrefutable – later equals larger.

Researchers at the University of Southern Mississippi asked young athletes to train with weights at different times of day and recorded the results. While all participants showed similar improvements in strength, the group that trained at 6pm gained more muscle mass than those who worked out at 10am. Plus, the evening group remained slightly leaner than the early-risers at the end of the experiment.

The benefits of doing your bum-booty building workout later in the day make biological sense. For a start, levels of the stress hormone cortisol (useful for getting you out of bed, less helpful for your gains) peak early in the morning. Also, your metabolism slows down naturally as the day progresses, but the evening reps force it to speed up again. That means you’ll burn more energy over the whole day, which equals more defined muscles.