Only a handful of things divide gym friends faster than the question: Are you a morning or a night exerciser? Believe it or not, the answer could shift how you feel during your day, how well you sleep at night, and even how many reps you hit at the gym. Most people pick a time based on jobs, family stuff, or when they finally get the urge to move, but the science behind best time to exercise goes much deeper. Wake up at 5am to run, or squeeze in a circuit at 9pm—your body actually reacts very differently depending on when you move it. Nuances about metabolism, energy cycles, motivation, and willpower make this debate more than just a matter of routine. Let’s pull apart the myth, see what the research says, and spot where your own schedule fits best.
Ever wondered why some people spring out of bed ready to sweat, while others can barely imagine lunging before noon? It’s not just willpower—blame or thank your body clock, known as the circadian rhythm. This internal timer manages when you feel awake or tired, but it also quietly tweaks your hormones, core body temperature, and even your muscles’ reaction time.
From sunrise to bedtime, hormones like cortisol and melatonin peak and drop. Cortisol, often dubbed the “wake up and go” hormone, is highest at dawn. It roughs up your stress response and helps you feel alert—not a bad perk if you want energy for a sunrise workout. On the flipside, late afternoon and early evening see rises in testosterone and body temperature, meaning your strength and muscle power might top out after work, which is handy for lifting heavy or chasing personal bests at night.
Sleepiness and sluggish reaction times are most common in early morning, right before your body temp starts climbing. By afternoon and evening, your joints are warmer, you’re less injury-prone, and reaction times tend to peak. Strength-wise, studies like the 2019 review in the journal Sports Medicine confirm people usually lift more and have faster times in the early evening—that’s when your muscles literally fire up faster. But, while performance markers may shine later, the best time is the one you’ll actually do. If work, kids, or uni only leave mornings, your body will adapt over weeks and months—a concept researchers call “temporal specificity.”
As far as burning fat? Your metabolism gets a slight bump in the morning, especially before breakfast. That’s called fasted cardio. Even though it's popular, it doesn’t always mean bigger fat loss if you have a morning snack or eat more later. Fat burning really comes down to what you do consistently and what fits your daily energy.
Here’s a quick peek at how circadian rhythm can mess with or help your workouts:
| Time | Hormones/Body | Workout Benefits |
|---|---|---|
| Early Morning (5am-8am) | High cortisol, low body temp | Better fat burn, easier routine-building |
| Late Morning (9am-12pm) | Rising temp, balanced energy | Balanced performance, fewer injuries |
| Afternoon/Evening (4pm-8pm) | Higher testosterone, peak temp | Peak strength, speed, best times for PBs |
Your body clock might lean early or late (this is your “chronotype”), and you can shift it a bit with habits, but not totally. Night owls can force morning sweat sessions but will usually feel grumpy at first; same goes for early risers flipping to midnight runs. Let your sleep needs and real-life schedule guide you more than just believing in one-size-fits-all science.
If you start training at dawn, you’re not alone—about one third of people say they’d rather get it over with first thing, according to a 2022 Gallup poll. It’s not just about custom: there are some solid perks for training in the morning, especially if you struggle staying on track or want a better mood through the day.
First up? Discipline. There’s something about ticking off your workout before distractions and work stress pile up. Studies like the one out of Appalachian State University in 2019 found that morning exercisers were more likely to make movement a regular habit than those who waited until night. Early trainers even had lower blood pressure and less stress through the day, possibly because exercising boosts dopamine and serotonin at just the right time.
For people trying to drop kilos, fasted morning cardio is all the rage. The theory: your body taps into fat stores more readily when your blood sugar is lowest, right before breakfast. While this is true in the short term, research (like the British Journal of Nutrition, 2016) shows the effect on fat loss after weeks or months isn’t massive—the real secret is sticking with it. Morning routines also help people who have trouble sleeping; working out before breakfast leads to better quality shuteye compared to night sessions, which can ramp up adrenaline and delay sleep in sensitive types.
But, there are downsides. Your joints and muscles are stiffer at dawn, meaning you’re slightly more likely to pull a muscle if you don’t warm up fully. You also might find performance (like max lifts or fastest kilometers) is a smidge lower than evenings, when your body’s really humming. And, let’s be honest—in winter, those 5:30am alarms are a killer.
For people who want less mental clutter and a better chance at habit-building, morning workouts are gold. Plus those clear, cool Aussie mornings just feel better somehow—you get sunrise, fewer crowds, and more time for post-work fun.
Night time training has a reputation for being the last option, but a ton of data says it’s when your body is at its absolute best for high-intensity efforts. Around 4pm to 8pm, your coordination, stamina, and muscle strength all hit their peak. If smashing personal bests and lifting heavier is your aim, late day is your golden hour.
The core reason? Your body temperature is up, reaction times are snappier, and testosterone—which fuels muscle protein synthesis—spikes up. That’s why plenty of pro athletes (think the AFL or NRL guys here in Australia) prefer afternoon or sunset sessions, and why local gyms often have their biggest crowds at night. A 2021 study in the Journal of Strength and Conditioning Research found that heavy lifters consistently pulled their best numbers after 5pm, not before lunch.
There’s more: night workouts can act as a major stress reliever after a tough day. Exercise dumps out the stress hormone cortisol, replacing it with mood-lifters like endorphins. Ever noticed how weights or a hard run make work worries just melt away? Plus, for shift workers, parents, uni students on weird schedules, or those who just plain hate mornings, night sessions slot in so much easier—and you’re more likely to train harder because you’ve had time to eat, hydrate, and shake off fatigue.
So, what’s the catch? For some, late night exercise—especially intense sessions after 8pm—can spark a burst of adrenaline that drags out sleep time. About 20% of people are sensitive to this. Cooling down properly, sticking to moderate effort, or finishing by 7:30pm usually solves it. But if your sleep is fine, there’s no study showing evening exercise is bad for you.
The best part of evening training is flexibility. Plan healthy dinners after your routine, meet friends at late fitness classes, or crank your favorite playlist without waking anyone up. The energy at gyms and running tracks at night is buzzy—a perfect antidote for anyone who feels flat before work. And if you’re measuring progress by numbers, don’t be shocked if your lifts go up by 5-10% in just a few weeks compared to mornings.
Here’s the not-so-secret truth: the timing of your workout is only “best” if you can do it consistently and it fits your life. Nothing derails a new fitness goal faster than wrestling with a schedule that just won’t cooperate. If you work early shifts, have school drop-off, eat dinner late, or just hate certain wake-up times, that’s your reality. And guess what? Your body, in Perth or anywhere else, will adapt far more than people realize.
Look at famous examples. Aussie Olympian Sally Pearson swears by morning speed drills for habit and discipline, but footy star Nat Fyfe does beast-mode training after 6pm because it hits his power sweet spot. What they share is regularity—their bodies know when to ramp up because they train at the same time, nearly every day.
Here are a few steps for picking a time that’ll actually work for you:
Here’s something wild: studies from Curtin University in Perth (2022) found that people who exercised at the same time every day, no matter when, improved fitness more quickly than people who bounced all over the clock. Your body likes predictability.
If you’re working toward a body comp goal (fat loss, muscle gain) or something specific like managing stress or building social time, match the mood of your ideal workout slot. Morning = focus and structure. Night = intensity and relaxation. It really comes down to ownership of your routine.
Lastly, experiment with longer or shorter sessions based on how you feel—maybe twenty hard minutes at sunrise, or an hour of easy movement after dinner. The right slot isn’t set in stone—your life, your rules. That’s how fitness becomes lifestyle, not a passing phase.
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