The question behind the question
People usually ask how long a workout should be because they want a number they can trust. One video shows a two-hour session and calls it dedication. Another promises a full transformation in twenty minutes. A friend says anything past an hour is wasted. With that much noise, it is easy to judge a session by the clock and forget what the session was for.
The last article, on how many days to train, settled the shape of your week. This one deals with the size of each day. It answers one question: how long should each training session be, and how do you decide?
The simple answer
A workout should be as long as the work it needs to contain, and no longer. For most people, most sessions land somewhere between 30 and 75 minutes. The useful length comes from adding up the parts:
- a warm-up that prepares you for the main work
- the working sets your program needs, with the rest each one requires
- any conditioning the program includes
- a short wind-down if you want one
Duration is the result of those choices, not a target in itself. The exception is when your time really is fixed. Then the clock becomes the constraint, and you design what goes into the session so it fits, cutting in a deliberate order rather than at random.
Why the clock is the wrong thing to aim at
Earlier lessons showed what actually drives adaptation: enough hard sets for the muscles you are training, appropriate load and effort, enough rest to make each set count, and, for aerobic goals, enough minutes at the right intensity. Time is the container those things sit in. It is not the stimulus.
A 90-minute session with 35 minutes of scrolling between sets delivers less than a focused 45-minute session. A 20-minute session can be very useful if it contains the right work, and nearly useless if it is a random circuit with no progression. Your body cannot tell how long you were in the building. It responds to what you did while you were there.
What the evidence says, and what it does not
Keep the layers apart here, because duration is an area where coaching opinion is often presented as science.
Research evidence
- Volume matters, with diminishing returns. A meta-analysis of resistance training studies found that more weekly sets per muscle were associated with more muscle growth, with smaller additional gains as volume rose. A longer session can therefore help, but only if it holds more productive work that you can recover from.
- Rest on heavy lifts protects strength. A systematic review found that longer rest between sets tends to favour strength gains, especially on heavy multi-joint lifts, and a trial in trained men found that 3-minute rests produced greater strength and muscle gains than 1-minute rests at similar set counts[1]. The American College of Sports Medicine position stand recommends roughly 2 to 3 minutes of rest on heavy core lifts and 1 to 2 minutes on others. Rest is real training time, which is why heavy strength sessions run longer.
- For health, every minute counts. The World Health Organization guidelines recommend 150 to 300 minutes of moderate aerobic activity a week (or 75 to 150 vigorous), plus muscle-strengthening activity on two or more days, and state that some activity is better than none. Short bouts add up toward these totals.
What the evidence does not show
There is no good evidence for a fixed cut-off, such as 45 or 60 minutes, after which training stops working or becomes harmful. Claims that hormones turn against you after an hour are not a sound reason to cut a well-designed session short. What does happen in long sessions is ordinary fatigue: later sets get worse, focus drops, and recovery costs rise. That is a coaching consideration, not a stopwatch rule.
Coaching principle and APEX framework
The coaching principle is simple: build the session from its required parts, keep the quality of each set high, and stop when the planned work is done. The APEX framework adds one thing: the right length depends on the person, the stage and the goal. The individual decision is yours, and it starts with how much time you can reliably give.
How to work out your session length: the time budget
You can estimate any session in a couple of minutes with this budget:
- Warm-up: usually 5 to 12 minutes, including a few lighter ramp-up sets on the first main lift.
- Working sets: number of sets multiplied by (time to do the set plus rest after it).
- Changeovers: about 1 to 2 minutes each time you move to a new exercise and set up.
- Conditioning or finisher: whatever the program prescribes, if anything.
Three illustrations, using round numbers:
- Foundation full-body session. Warm-up 8 minutes. Five exercises of 2 sets each is 10 sets. Each set takes about 45 seconds plus 90 seconds rest, so roughly 2 to 2.5 minutes per set, about 23 minutes. Five changeovers add about 6 minutes. Total: around 35 to 40 minutes.
- Muscle-focused upper session. Warm-up 8 minutes. Sixteen working sets at about 2.5 minutes each is about 40 minutes. Changeovers 8 minutes. Total: about 55 minutes. Pair some exercises and it drops toward 45.
- Strength session. Warm-up plus ramp-up sets on the main lift take 12 to 15 minutes. Four heavy sets with 3 minutes rest take about 15 minutes. A second lift and two support exercises add 25 to 30 minutes. Total: 60 to 75 minutes, and that is appropriate.
If your planned session and the time you have do not match, you now know exactly where the gap is.
When time is fixed: what to cut, in order
Busy parents, shift workers and professionals often have a hard ceiling. When the budget is bigger than the time, cut in this order:
- Dead time first. Phone, wandering, long equipment hunts. Set out what you need, use a timer for rest, and keep your phone for the timer and logbook only. This alone often saves 10 to 15 minutes.
- Pair exercises that do not compete. Alternate a push with a pull, or an upper exercise with a lower one, resting between them. Each muscle still gets its rest while the clock moves faster. Avoid pairing two heavy lifts that tire the same muscles or your trunk.
- Drop the lowest-priority accessory. Keep the exercises that serve your primary goal. The fourth arm exercise goes before the main lift does.
- Trim a set from accessories. Going from 3 sets to 2 on smaller exercises keeps most of the benefit for less time.
- Shorten rest on small exercises only. Single-joint work tolerates 60 to 90 seconds well. Keep fuller rest on heavy multi-joint lifts and on power work.
Two things should not be cut to zero: a short warm-up, and the main work for your goal. If cuts still are not enough, the better answer may be in the previous lesson: spread the same weekly work across more, shorter sessions. Weekly time is the real budget. Three 60-minute sessions and four 45-minute sessions hold the same total.
Duration across the APEX stages
Session length often changes as a person moves through the stages, but it is not a ladder where longer means better.
- Restoration: often short, perhaps 10 to 30 minutes, sometimes more often in the week. The aim is tolerance and habit, and a session that finishes with energy left is a success. Where a health condition, injury or recovery from illness is involved, a qualified healthcare professional should guide the dose.
- Foundation: usually 30 to 45 minutes. A short session you complete every time beats a long one you skip.
- Transformation: often 45 to 60 minutes, with resistance work first and any conditioning after or on separate days.
- Development: often 50 to 75 minutes, as volume, heavier lifts and longer rest add time.
- Performance: driven by the specific goal. Some sessions run longer, and some athletes split work into two shorter sessions on the same day to keep quality high.
- Mastery: whatever length sustains high capability alongside health, recovery and life.
How duration interacts with program type
The program structures earlier in this phase each create typical session lengths. Full-body training on two or three days usually means somewhat longer sessions, because each day covers every main movement family. Upper / lower, Push / Pull / Legs and body-part splits spread the work across more days, so each session can be shorter or can hold more work per muscle. Strength programs run longer because of rest. Conditioning sessions are set by minutes and intensity rather than sets. None of this changes the core rule: the structure you chose decides what each day must contain, and that decides its length.
Common mistakes
- Judging a session by how long or how sweaty it was. Exhaustion is not a measure of progress. The logbook is.
- Adding exercises to fill an hour. Extra sets that you cannot recover from, or that are done badly at the end, add fatigue without adding much stimulus.
- Cutting rest on heavy lifts to save time. This lowers the quality of the sets that matter most.
- Skipping the warm-up when short of time. A shorter warm-up is fine; none at all usually makes the first working sets worse.
- Planning sessions you cannot attend. A perfect 75-minute plan that you do half the time is weaker than a 40-minute plan you do every time.
- Letting length drift without noticing. Sessions quietly grow from 50 to 80 minutes through extra chatting, extra exercises or longer rests, and progress becomes harder to read.
What it can look like in real life
Consider an illustrative example, not a real case. A parent with two young children can reliably train for 40 minutes, three mornings a week, before work. Their plan from a video runs 70 minutes, so they keep stopping halfway and missing the leg work at the end. Using the time budget, they keep the main squat and hinge work early, pair pushes with pulls, drop one arm exercise, and trim accessories to two sets. The session now fits in 40 minutes, every planned set gets done, and the logbook starts to show steady progress. Nothing about the session became more impressive. It became executable.
What not to copy
Elite athletes and professional physique competitors sometimes train for long periods, or twice a day. They often have years of training behind them, recovery built into their whole day, and a specific competitive goal that requires it. Their session length is the result of their needs, not a standard for yours. Copying the length without the context usually means copying the fatigue without the benefit.
Your next best step
Time your next three sessions honestly. Write down the start time, the finish time, and the number of hard working sets you completed. Then compare that with the time budget for what your program actually requires. If the session ran long, find the biggest leak, usually dead time, and fix that one thing first. If it cannot fit at all, apply the cutting order above or spread the work across one more day. One change, then repeat.
Where this fits in APEX
Session length belongs to the Program and Execute steps of the APEX loop. The program decides what the session contains; execution decides whether it actually happens in your real week. Getting the length right is what turns a good plan on paper into training you can repeat, and repetition is what lets progression happen. The next lesson, How to Progress a Program, builds on exactly that: once your sessions fit your life and get done, how do you make them gradually more demanding over time?
