How long should a workout be? 45 minutes is usually enough

Most people asking how long a workout should be are really asking whether the time they have is enough. It usually is. If you've picked up the idea that anything under an hour doesn't count, you can put it down. A long session is mostly resting between sets, which is normal, and a focused 45 minutes holds enough hard sets to build strength and muscle. It's not the lazy version.

Going to a 45-minute class? It counts, with one condition for classes. Just want the workout? Skip to the session.

How long a workout should be for your goal

These ranges are ours, built from the guidance below and the arithmetic further down. They're wide on purpose. For lifting, most of a session is rest between sets, so the length mostly follows how many sets you do and how long you rest. For cardio, what counts is the weekly total, so a shorter session just means one more of them.

The American College of Sports Medicine's 2026 guidance asks healthy adults to work every major muscle group with real effort at least twice a week, and it calls strength training safe for them at any age.¹ If you're older or brand new, all of this applies to you too.

How long should you work out a day?

About 20 to 30 minutes a day, on average, covers the official minimum. The CDC asks adults for at least 150 minutes a week of moderate activity, like brisk walking, or 75 minutes of vigorous activity, plus muscle strengthening on 2 or more days that works every major muscle group.² Spread over seven days, 150 minutes is about 21 minutes a day. The CDC's own example is 30 minutes, 5 days a week, and it says you can break that into shorter chunks.

You don't need to train every day, and the days don't have to match. One week that clears both targets without a single long session:

• Three days a week: the 45-minute strength session further down.
• Five days a week: a 30-minute brisk walk, on its own or split into a 15-minute walk before work and another after.

More is fine if you enjoy it: the CDC says going past 150 minutes brings even more health benefit.² For lifting, a longer session mostly buys more rest and a few more sets. Whether you need those is what the rest of this article works out.

What "hard" means, and why it's less brutal than it sounds

The whole answer hangs on one condition: stop each set when you could only have done one to three more good reps. The last couple of reps slow down and take real effort. If you could chat through the final rep, the weight is too light.

You don't need to grind until the weight won't move. Across 15 studies, taking sets all the way to failure gave little or no extra muscle growth compared with stopping short,³ and the ACSM guidance found that training to failure didn't reliably change results either.¹ Hard doesn't have to mean miserable. More on finding the line in training to failure, how close is close enough.

If your 45 minutes is a class

Plenty of people asking this question go to a class. F45 is named after its 45-minute class length and rotates resistance, cardio and hybrid classes, all circuits of timed stations, for example 40 seconds of work and 15 seconds of recovery. BODYPUMP comes in 30, 45 and 55 minute versions, with lighter weights than a heavy lifting session and lots of reps (more than 1,000 in the 55-minute class). Les Mills itself says it builds strength endurance, which means being able to keep going for many reps with a lighter weight.⁴

So is a class enough for real results? For fitness and heart health, yes. A class that keeps you breathing hard goes a long way toward the CDC's weekly cardio minutes, and two or three a week add up to 90 to 135 minutes. For fat loss it's the same as the table above: the class helps, and your diet moves the scale more.

For muscle, it comes down to how hard the last reps are. A review of 21 studies found that light weights grew muscle about as well as heavy ones, as long as every set went to failure, the point where you can't do one more rep. Heavy weights still won for maximum strength.⁵

Those studies used ordinary lifting sessions, not classes, and a class won't take every track to failure, so this part is our read of the research: a class builds muscle when the end of each station or track is genuinely hard, and you pick up heavier weights as it gets easier.

The class test: when the buzzer goes or the track ends, could you have done more than three more good reps? Then take the heavier weights next time. If a class has felt the same with the same weights for months, it's probably keeping you where you are rather than building.

If getting stronger is your goal, keep the class you enjoy and add one session a week with heavier weights and fewer reps, like the one further down.

What actually fits in 45 minutes

A set of 8 to 12 reps at a steady pace takes about half a minute. Allow 40 seconds once you count getting into position. The rest of a workout is warming up, resting and moving between exercises.

So "is 45 minutes enough?" is really "how many hard sets fit in 45 minutes?" Here's the arithmetic for a session with a 6-minute warm-up, four exercises and a minute to set up each new one. Straight sets means one exercise at a time: a set, a rest, the next set.

• Straight sets, 3 min rest: 10
• Straight sets, 2 min rest: 13
• Straight sets, 90 s rest: 16
• Paired sets, 1 min between: 21

Our arithmetic: 6-minute warm-up, 40-second sets, a minute to set up each of four exercises

The tempting move is the 90-second bar: cut the rest and cram more in. Don't lean on it for your main lifts. Short rests leave you weaker on the next set, so you lift less, and a hard set done tired is worth less. More on that in rest between sets, why three minutes beats one.

The last bar is the better trick: paired sets. Do a set of a press, rest a minute, do a set of a row, rest a minute, back to the press. Each muscle still gets more than two and a half minutes between its own sets, and you're never standing around.

Does it work? Across 19 studies, paired sets (supersets, in the research) got the same total work done in less time, with similar long-term gains in strength and size. Pairs of opposing muscles, like that press and row, kept the work up best. They do feel harder.⁶

One safety rule: the researchers who reviewed time-saving methods advise against supersets on heavy free-weight lifts like the barbell squat and bench press.⁷ So our rule is to pair dumbbell, machine and bodyweight moves, and give a heavy barbell lift its own time.

What that adds up to over a week

Muscles don't count minutes. They count hard sets across the week. A simple full-body session covers four basic movements, each working a different big muscle group: a squat, a hinge (bending at the hips, like picking a box up off the floor), a push and a pull. Share the 13 straight sets or 21 paired sets from the chart evenly across the four:

An upper and lower body split over four days lands on the same count as the four-session row. And the table runs a little low, because a row also trains your biceps and a squat your glutes; the full picture is in how many sets per week your muscles actually need.

The study that timed it

Most advice about session length is guesswork. One study actually put a stopwatch on it.

In a 2019 study published in Medicine and Science in Sports and Exercise, Brad Schoenfeld and colleagues followed 34 men who already lifted, split into three groups, for 8 weeks. Everyone did the same seven exercises three times a week, with every set taken to failure. The only difference was one, three or five sets per exercise.⁸

The 40-minute group is the nearest thing to your 45-minute workout: 21 hard sets in about 40 minutes, with 90-second rests and no warm-up counted. Fitting those 21 sets into 45 minutes with a warm-up and longer rests is what pairing is for.

Strength rose in all three groups, and the study found no significant difference between them. Size was different: more sets meant more growth. The clearest gap was between one and five sets, where the front of the thigh grew 3.4% with one set and 12.5% with five. Three sets landed in between, and the data couldn't firmly separate it from either end.

Of those 40 minutes, only about 10 were spent lifting. Twenty-one sets of 24 to 36 seconds each comes to 8 to 13 minutes. The other 30 or so went on resting, setting up and moving between exercises, which is why a short session isn't a watered-down one.

You don't need to copy the failure part: as above, stopping a rep or two short gives up little or nothing. And this was a small group of trained men, so treat the numbers as a direction, not a law.

A 45-minute session you can do tonight

This is full body, so do the same session two or three times a week. Each step has a home version for a pair of dumbbells and a gym version. Pick a weight you can lift for the reps listed with one to three to spare. When every set reaches the top of the range and still feels like it had reps left, go a little heavier next time. With fixed dumbbells at home, slow the lowering to three seconds or move to a harder version, like a split squat instead of a goblet squat.

If you have a heart condition, a recent surgery, an injury that's still healing, or you're pregnant, ask your doctor or physio what fits before you start.

1. Minutes 0 to 6: warm up for your first lift

   Two minutes of easy movement: march in place, swing your arms, do a few slow bodyweight squats. Then two light sets of your first exercise, at about half and then three-quarters of your working weight. A long general warm-up does little when time is short, so skip it.⁷

2. Minutes 6 to 17: one big leg exercise, on its own

   Home: a goblet squat (hold one dumbbell upright against your chest, sit down between your heels, stand back up) or a split squat (one foot well in front of the other, holding a dumbbell in each hand, lower your back knee toward the floor and come back up). Gym: a back squat with a barbell across your upper back, or the leg press machine.

   4 sets of 6 to 10 reps, resting 2 to 3 minutes. This is your heaviest lift, so it gets full rest and no pairing.

3. Minutes 17 to 28: a push and a pull, paired

   Home: a dumbbell press (lie on the floor or a bench and push the dumbbells up from your chest), paired with a one-arm row (one hand and knee on a chair, pull a dumbbell up toward your hip). Gym: a dumbbell bench press or a chest press machine, paired with a seated cable row (sit and pull a handle toward your belly).

   3 rounds of 8 to 12 reps each, with about a minute between moves.

4. Minutes 28 to 39: a hinge and an overhead press, paired

   Home: a Romanian deadlift (stand holding the dumbbells in front of your thighs, push your hips back with a flat back and let the weights slide down to just below your knees, then stand tall), paired with a seated shoulder press (push the dumbbells from your shoulders to overhead). Gym: the same moves, or a hip thrust (shoulders on a bench, a weight across your hips, push your hips up) and a shoulder press machine.

   3 rounds of 8 to 12 reps each, about a minute between moves.

5. Minutes 39 to 45: a second pull and your middle, then stop

   Home: a reverse fly (bend forward with light dumbbells and raise your arms out to the sides), paired with a dead bug (lie on your back with arms up and knees bent over your hips, then slowly lower one arm and the opposite leg toward the floor and swap). Gym: a lat pulldown (sit at the machine and pull the bar down to your upper chest), paired with a plank (hold a straight line from head to heels on your forearms and toes).

   Two rounds. Then you're done, even if you feel like adding one more thing. That urge is how 45 minutes turns into 70.

That's 20 hard sets. Done three times a week, your legs get about 21 (12 from squats, 9 from the hinge) and your back about 15 (9 from the rows, 6 from the pulldown or reverse fly). Your chest and shoulders get about 9 each from their own presses, just under the 10 mark, though the chest press also works the front of your shoulders, so they're closer than that looks. At home, those 6 reverse fly sets also work the backs of your shoulders. If you want more chest, add a fourth round of the press and row, or a few sets of push-ups on another day.

New to lifting? Do 2 sets of everything instead of 3 or 4, and you'll finish in about half an hour. Two sets per exercise is the minimum the ACSM guidance advises for healthy adults.¹ Add the third set after a few weeks. For what to expect and when, see how long until you see results from lifting weights.

You can run this on your own with a notebook and a timer. If you'd rather someone else held the clock, here's what that looks like.

Where 45 minutes quietly goes

Most short sessions that feel unproductive aren't too short. They leak.

• The phone. One message during a 2-minute rest, and it's a 6-minute rest. Use the phone as a timer and nothing else, or put it on the floor across the room.
• The long warm-up. Fifteen minutes on the bike feels responsible and eats a third of your session. Warm up for the first lift instead. Here's what actually prepares you to lift.
• Too many exercises. Every new exercise costs a minute or two of setup. Eight exercises means about ten minutes of shuffling. Four or five, with more sets of each, gets more done.
• Deciding what's next. Write the session down before you start, including a backup for any machine that might be taken.
• The trip there. "45 minutes in the gym" can be 80 minutes door to door. If that's what's breaking your week, lunch-break workouts and training at home between meetings show two ways around it.

When 45 minutes isn't enough, and when less is fine

It isn't enough if you compete in powerlifting or bodybuilding, or you're an experienced lifter chasing every last bit of size. In the timed study, five sets beat one for growth, and getting every muscle up near 18 to 20 sets a week takes a fourth session or longer ones. That's a small group of people, and they usually know who they are.

Less is fine for everyone else on a bad week. The 13-minute group in the timed study still got stronger. A review of trials on trained men found the same. One all-out set per exercise, two or three times a week with a fairly heavy weight, raised the most they could lift for one rep by about 17 kg (38 lb) in the squat and 8 kg (18 lb) in the bench press, over 8 to 12 weeks.⁹ More sets work better, but one set beats zero.¹

So on a short day:

• 30 minutes: warm up, do the leg exercise and the push-pull pair, and leave.
• 15 minutes: one hard set each of a squat, a hinge, a push and a pull.

Either way the week still counts. We lay out the full floor in the minimum effective dose of exercise, per the research, and how far a small schedule can go in how to make progress training three hours a week.

What a coach on the call does with your 45 minutes

Everything above works on your own, but it all hangs on one judgement: was that set hard enough? That's the one you're worst placed to make mid-set, tired, with a timer running. It's the job we built Bespoke Fit to take off you, along with the clock and the planning.

Every session is a live 1‑on‑1 video call with your own coach, in our app on iPhone, Android or a browser. You train wherever you can prop a phone up: a spare room, a garage, a hotel room. Your coach watches through your camera, so every set is seen.

Here's that squat block with a coach on the call. You're on your second set of goblet squats, and on rep 8 your knees start drifting in. Your coach says "knees out" while you're still in the rep, not a day and a half later from a video you sent in. If you wear an Apple Watch or a Bluetooth heart rate strap, your coach sees your heart rate live on their screen. Yours is slow to come down after that set, so you get an extra 30 seconds. The third set moves cleanly with reps to spare, so the fourth goes up 5 lb. You didn't have to judge any of it yourself.

Sessions run 45 to 90 minutes at the same price, and most people settle at around an hour. If 45 minutes is what your day holds, tell your coach and that's what they book; on a day with more room, the extra time costs nothing.

That only works if your coach knows you. Each coach has 12 members at most, and we hold to that when we assign coaches, so yours remembers what you squatted last week because they wrote that session and watched you do it. Every coach spends 90 days onboarding with our founder before taking a member. You don't pick from a list: a head coach meets you on a 30-minute strategy call and matches you. Between sessions you message your coach, photos included. Deqa, 27, a member, put it like this:

2 months in and I haven't skipped a single workout, which has literally never happened before. I don't have to plan anything. I just put on my clothes and fill my water bottle, and my coach does the rest.

What it costs, and who should skip it

14 days free, then $299 a month, cancel anytime, for as many sessions as you book. Three a week is about 13 sessions a month, so about $23 a session; four a week, about $17. A personal trainer in the US averages $50 to $90 a session.¹⁰ When you pay by the session, every extra workout is a decision about money. Here the fourth one in a week costs nothing extra, so your coach plans the week your goal needs, which, going by the weekly table, is often three or four sessions. The 14 days start at your first session, not at signup, and we remind you 3 days before the first charge.

Skip it if:

• You already train like this two or three times a week, alone or in a class you love. Keep going. It's working, and it costs less.
• $299 a month is out of reach. The session above costs nothing to run.
• Your goal is mostly the scale and you want meal plans. We don't do nutrition coaching.
• You want someone to spot a heavy barbell, or to train whenever the day allows. Nobody on a video call can spot you, and our sessions are booked with your coach.

If what you want is two to four of these sessions a week, run live by someone who knows your numbers, that's exactly what the 14 days are for.

Common questions

Is a 45-minute workout enough? Yes, for almost everyone, classes included. It fits 10 to 21 hard sets, which at two or three sessions a week is enough to build strength and muscle. Only competitive lifters and people chasing every last bit of size usually need more.

Will I lose progress if I cut from 90 minutes to 45? Probably not much. For strength, the timed study found no significant difference between the 40-minute and 68-minute groups. For size you'll fit fewer sets, so growth may slow a little, but pairing exercises and a short warm-up keep a good share of the hard sets a 90-minute session holds.

Does the 45 minutes include the warm-up? In our plan, yes. The first six minutes are the warm-up, and the set counts in the chart already allow for it. Getting changed and the trip to the gym are not included, and they can add half an hour or more.

Should I squeeze cardio into the same 45 minutes? You don't have to. Cardio and strength are separate targets, so a brisk walk or a bike ride on other days counts toward your cardio. If you want both in one session, lift first while you're fresh and keep the cardio at the end.

Sources

1. Currier et al., 2026. American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews. Medicine and Science in Sports and Exercise. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

2. Centers for Disease Control and Prevention. Adult Activity: An Overview. CDC. ↩ ↩²

3. Refalo et al., 2023. Influence of Resistance Training Proximity-to-Failure on Skeletal Muscle Hypertrophy: A Systematic Review with Meta-analysis. Sports Medicine. ↩

4. F45 Training, What is F45; Les Mills, BODYPUMP. Both checked November 2026. ↩

5. Schoenfeld et al., 2017. Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. Journal of Strength and Conditioning Research. ↩

6. Zhang et al., 2025. Superset Versus Traditional Resistance Training Prescriptions: A Systematic Review and Meta-analysis. Sports Medicine. ↩

7. Iversen et al., 2021. No Time to Lift? Designing Time-Efficient Training Programs for Strength and Hypertrophy: A Narrative Review. Sports Medicine. ↩ ↩² ↩³

8. Schoenfeld et al., 2019. Resistance Training Volume Enhances Muscle Hypertrophy but Not Strength in Trained Men. Medicine and Science in Sports and Exercise. ↩

9. Androulakis-Korakakis et al., 2020. The Minimum Effective Training Dose Required to Increase 1RM Strength in Resistance-Trained Men: A Systematic Review and Meta-Analysis. Sports Medicine. ↩

10. Bark, updated January 16, 2026. How much does a personal trainer cost?: "The average personal trainer cost is $50-90 per session" in the US. Read November 12, 2026. ↩