When’s the Best Time of the Day to Train for Muscle Growth?

When is the best time to train?

The first thing to discuss is circadian rhythms. You have one unique to you, guided by the light changes in our environment (ie, night and day).

Your circadian rhythm is an assortment of physiological processes that repeat about every 24 hours, and regulate things like including hunger, digestion, sleep, bowel movements, body temperature, and hormone levels.

Your sleep-wake cycle is an obvious process governed by a circadian rhythm.

But sleep is only one rhythm. There are in fact many rhythms (plural!) that then govern the best time to train for muscle growth and strength.

We'll return to the "rhythms" and their effect in a moment, but here's the short answer: training in the afternoon is better!

Is the morning or afternoon better for training for muscle growth and strength?

A recent review found that the late afternoon is the best for anaerobic training. And such is backed by other research like this, which examined subjects training between 6:30 am - 10:00 am or from 4:30 pm - 8 pm.

The researchers reported that whilst strength and endurance performance improved basically the same for both periods, the evening group gained notably more muscle.

So, what's at play here? Why are afternoons seemingly so much better?

Well, research suggests this is because muscle anabolic signalling is higher after training in the afternoon than in the morning. And the testosterone cortisol ratio plays a key role.

Obviously, when testosterone is higher and cortisol lower, it's a more favourable environment for muscle growth. 

And the ratio is higher in the afternoon and the evening; as exercise results in minimal rises in cortisol and maximum rises in testosterone in the afternoon.

The other factor at play is core body temperature; another one of our "rhythms." 

When our bodies temperature is higher, our muscle blood flow increases, as does joint mobility. 

And this happens in the late afternoon to early morning.

Most of us experience higher muscle activation in the evening; it's also when muscular strength and power are at their peak.

Scheduling your workouts for muscle growth and strength

So, when's the ideal precise time to work out, then?

Well, assuming you sleep at around midnight and wake at around 8 am, research suggests anytime between 2:30 pm - 8:30 pm.

For those who don't fit into the regular sleep and wake cycle, 6-7 hours after waking would be ideal.

But if you're a morning trainer and reading this freaking out, it might not be as bad as it seems. 

Science aside, the fact you're turning up and training is half the challenge. 

Considering actually making it to the gym is half the battle, it's certainly not all doom and gloom.

But the news gets even better than that for morning trainers!

This study examined 10 males aged 20, to see what effects exercise had on the circadian rhythm of cortisol at the lowest and highest points. They took blood at both cortisol points over a four-week period.

They found that "Exercising at the lowest and peak points of cortisol changed the body’s cortisol circadian rhythm."

In other words, train in the morning, and your body will get used to it somewhat (if you're consistent). The hindrance in performance from morning training will eventually be reduced.

However, it won't ever be as effective as evening training -- research shows performance won't be totally unaffected -- but the news is still good, nevertheless. 

But of course, you can get around this with a good pre workout and/or caffeine intake, a whey protein shake before training, and great supplements like creatine and beta-alanine to ensure you're at your best! 

The bottom line is that training in the afternoon is better for muscle growth and strength. This is because our anabolic signalling is higher in the afternoon, as is the ratio of our testosterone to cortisol.

The afternoon is also when our bodies temperature is higher, meaning our muscle blood flow and joint mobility increase, which is more favourable for resistance training. Moreover, muscular strength and power are at their peak here.

Research suggests anytime between 2:30 pm - 8:30 pm is the best for training, assuming your sleep-wake cycle is from about midnight to 8 am. For those who don't fit into the regular sleep and wake cycle, 6-7 hours after waking would be ideal.

Morning gym-goers who train at that time consistently will have their hindrance in performance reduced over time, but it will never be as effective as afternoon training.