Whether you’re a dawn runner or an after-work gym-goer, the latest research reveals when your body may be primed to perform at its best
WORDS: Ed Cooper PICS: Getty Images
Broadly speaking, there are two kinds of people — those who work out in the morning, bright-eyed and bushy-tailed, and those who wait until the sun is setting to lace up and put the work in. Whether it’s a pre-work 10K or an evening HYROX class to shake off any cobwebs from the day, it’s a natural impulse to wonder who’s getting the most from their workout and, crucially, if there’s any science to actually back it up.
The conversation has been brought about due to certain celebrities and thought-leaders, like Dwayne ‘The Rock’ Johnson, Mark Wahlberg and, interestingly, Barack Obama, publicising that they start their day with a morning workout, but it’s worth noting that several fundamental elements of human biology and physiology are at play whenever you choose to exercise.
Across the world of sport, for example, records are almost exclusively broken after the sun’s gone down, yet testosterone production — vital for building muscle and maintaining energy levels — tends to be lower in the afternoon than in the morning. So who’s getting it right — and does it really matter?
Wake-up call
Naturally, it makes sense to start with those getting after it in the morning. While a blaring 6AM alarm isn’t exactly the gentlest way to start your day, anchoring your morning around exercise may have several tangible benefits.
A study published in Oxford Academic discussed how researchers had 10 ‘moderately trained’ young men exercise at a constant intensity on a treadmill for 30 minutes at three different times: 7am, 7pm, and midnight.
Their results showed that morning exercisers spent more time in deep slow-wave sleep, which has a knock-on effect on nocturnal human growth hormone (HGH) release and blood pressure.
According to a YouGov survey, over half (55%) of British people say it’s ‘very’ or ‘fairly easy’ for them to get out of bed in the morning, meaning the findings of a British Journal of Sports Medicine study might be worth considering for the remaining 45% struggling to get to it.
During the study, researchers split participants into two groups — one starting the day with a 30-minute treadmill walk, one without — before both spent eight hours sitting (sound familiar?).
Perhaps unsurprisingly, the walkers were found to have a spike in cognitive function. A separate 2022 study published in the European Journal of Preventive Cardiology also found a connection between morning activity and improved cardiometabolic health (the combined wellness of your heart, blood vessels, and metabolic system) and highlighted that the benefit appeared independent of total physical activity levels — suggesting, then, that timing itself matters rather than volume only.
Going dark
On the other side of the coin, what benefits can evening lifters experience, or have they been outpaced by their peers rising-and-grinding? Evening types, it turns out, may have a cognitive edge.
A 2007 study found that night owls are better at applying “divergent thinking” (read: creativity) to visual problems. Two years later, psychologist Satoshi Kanazawa cross-referenced the bedtimes of over 20,000 adolescents with their intelligence test scores, and found a clear pattern: the smarter the person, the later they tended to stay up.
His explanation was characteristically provocative — that burning the midnight oil is “evolutionarily novel” behaviour and therefore arguably a marker of higher intelligence.
The idea has gathered a little more momentum since. A 2024 paper from Imperial College London drew on intelligence test data from more than 26,000 people and concluded that night owls showed superior cognitive function compared to early risers across the board.
As for energy and performance, both factors have been found to improve as the day progresses, with most people experiencing higher levels of power output and endurance, to the point where those putting in the work — cardio enthusiasts, in particular — can take up to 20% longer to reach exhaustion.
Evening exercisers could also have an edge when it comes to protein absorption — a 2016 Journal of Nutrition study found that working out in the evening significantly boosts the body’s overnight muscle protein synthesis — meaning your post-gym shake is put to better use while you sleep.
Partner these findings with further studies proving that peak strength can occur later in the day — between 4pm and 8pm, studies suggest — and increased core temperature in the afternoon boosts flexibility, muscle strength and joint pain, with a 1°C increase translating to a 2–5% improvement. Proof, then, that dragging yourself to the squat rack after a day of meetings needn’t feel so difficult after all.
