There are two kinds of people in the world; morning people and normal people.
Okay, that’s a little harsh. I guess I’m just jealous of those people who can go from sleeping to Laker Girl in 0.5 seconds when their alarm sounds. Frankly there are probably coma patients who beat me out of bed some days.
It’s all to do with something called your circadian rhythm. The cycle which regulates amongst other things, your sleep and waking patterns.
It’s generally thought that being slower in the AM can negatively affect workout efficiency too. Not just because if you roll into the gym late all the machines are taken (the early bird gets the leg press, as my old grandma used to say) but because of that rhythm again.
Your circadian rhythm also dictates hormone production, and testosterone is at its highest in the morning. As we know T is crucial to every part of physical performance, so it makes sense that most people would try and seize the start of the day.
So is it really a case of dawn or bust for getting the most out of exercise? Are there any advantages for those who like to hit the snooze button in the morning instead of the gym? The latest research suggests there is.
Before we break down which time of day might be better for your workout, it’s important that we look at circadian rhythms in a bit more detail.
The ongoing 24 hour cycle manages pretty much all our body’s internal systems. Not just our sleeping and waking pattern or hormone production, as we’ve touched on, but also metabolism, nervous system responses and physical performance.
Generally most people’s rhythms are synced quite closely, though the rhythm can be altered in a number of ways. Things like diet, exposure to light and darkness and amount of exercise taken, all make a difference.
The two main aspects you need to focus on from a fitness perspective are nervous system function and hormone output. These will both rise and fall at different times of the day, so depending on what you want to achieve, picking your spots is vital.
When you think about it, a lot of the arguments for a morning workout are more common sense than anything technical.
If you work out first thing, there’s less chance of events later in the day interrupting your routine. Also, exercise gives an energy and mood boost which, unless you’ve got a big night of partying planned, is only going to go to waste later on.
It’s true both T and mental alertness are at their highest early and these are both important ingredients for a great gym session. Unfortunately cortisol, a stress hormone, is also very high around this time. It has risen slowly all night to wake us. Cortisol can hurt training for a couple of reasons.
Firstly it can block the effects of T, cancelling out the advantage of the hormone being raised in the first place. High cortisol also causes breakdown of muscle tissue, meaning if you’re up with the sun in that weight room for better body definition, you’re in the right place at the wrong time.
Lastly, cortisol is released when you’re reaching your physical limit. It’s your internal white flag. The fitter you get the lower your cortisol response will become, but start with levels elevated and it may shave valuable time off how long you can keep working.
One area where early birds do seem to have the edge on night owls is metabolism. Studies show that putting yourself through your paces before you’ve eaten burns more calories. The body has to fuel itself with fat stores, rather than any carbs.
Also, a trial from BYU in 2012 found that women who did a 45 min workout early on were more likely to eat less for breakfast and make healthier food choices. They were also more active through the day.
Alright on the night?
When you think about how many elite sporting events take place in the afternoon at night it starts to feel obvious that delaying the burn a bit would have physical benefits.
Later sessions, once discouraged, are beginning to look like the way forward, especially for those aiming to build muscle.
A study from The European Journal of Experimental Biology in 2012 aimed to test if that morning spike in T really was worth it. 30 bodybuilders divided in to morning and evening groups and performances were compared. The evening group performed slightly better and researchers discovered that although T is lower, so is cortisol. Indeed the ratio actually more favourable than earlier in the day, arguably making later on more efficient.
A small study by French laboratory INSERM found by monitoring a group of healthy men training at 4 hour intervals, that peak muscle strength was 6pm and was its lowest at 6am. The also reported a link between max body temperature and greatest strength.
Body temperature, pain threshold and flexibility are all thought to peak around 4pm, and this perfect storm of factors could be the reason for a shift in attitude towards training later.
It might surprise you just how late some trials have found you can get the best from your body.
In the 1980s a study by Liverpool Polytechnic asked 14 competitive swimmers to compete over distances of 100m and 400m at 6:30 am, 9:00am, 1:30 pm, 5:00pm, and 10:00pm.
Researchers found that race times got faster later on. 100m swims were 3.5% faster and the 400m swims were 2.5% faster at 10pm compared to 6:30 am.
One of the main criticisms of late night workouts is that it raises not only your T, but heart rate, adrenaline, mood and body temperature. None of these things sound like they exactly help your system’s natural slowing down towards sleep, so some have suggested staying active too late may cause a degree of insomnia.
Again though, recent research has caused a rethink. A 2011 study from Finland found that volunteers who exercised vigorously late at night for just over half an hour, reported sleeping just as well as those who didn’t.
Similarly a survey by the National Sleep Foundation in America resulted in 83% of those asked saying that they slept better when they’d taken exercise. This training was limited to later on but it did include it.
So when is the best time to exercise?
It’s fair to say this is a surprisingly under-studied question. The evidence we’ve presented here isn’t conclusive enough to say for sure that evening or afternoon fitness routines are better than morning ones. More just that they aren’t at all bad.
For the most part differences in results depending on time of day are pretty small. Unless you’re an elite athlete who needs every edge they can get, any time is a good time for exercise.
As far as circadian rhythmns go, they are adaptable. So it’s not a case of building a workout round your body clock, more sticking to a stable regime and letting your natural cycles adjust gradually to it.
So for most of us there’s no real optimum time to be at the gym, but what that also means is there are no excuses!