How Long Should Your Workout Be to Build Muscle?

How long should a workout last if you want to gain muscle? Is 30 minutes enough? Is 90 minutes too long? Let’s find out.

You want more muscle than you have at the moment, and you want to make sure you’re doing everything possible to maximize the speed at which that muscle mass is gained.

However, while you don’t want to miss out on any gains, you don’t want to spend longer in the gym than is strictly necessary.

You may also have heard that spending too long in the gym can have an adverse effect on two hormones — testosterone and cortisol — which in turn will put the brakes on muscle growth.

So, what’s the answer? How long should a workout last if you want to build muscle?

On average, the ideal workout duration is going to be somewhere between 45 and 90 minutes. For most people, that’s long enough to get the job done.

With some programs, an effective workout might last around 30 minutes. With others, it might take you a couple of hours, especially if you’re resting for long periods between each set.

As long as your overall training program is set up properly, your workout duration isn’t something you need to spend any time worrying about. Let it take as long as it takes to get the job done.

That’s the short answer. The long answer, as ever, starts with “it depends.”

How Much Time Should You Spend in the Gym to Build Muscle?

An effective workout can last 30 minutes, 45 minutes, 90 minutes, or even two hours. It all depends on a number of factors, including:

• What your goals are
• Your training frequency
• The type of training you’re doing
• The amount of stimulation your muscles need to grow

Let’s take a look at each in turn.

What are your goals? I know you want to build muscle, but how much muscle exactly? Are you planning to slip on a pair of posing trunks and step on stage in a physique contest? Or do you just want to beef up certain muscle groups, such as your chest, shoulders and arms? 

Are you training for strength or hypertrophy? A bit of both? Your goals should dictate the type of training schedule you follow, and the length of your workouts will vary depending on what those goals are.

How quickly do you want that muscle to be built? You might be in a hurry to gain as much muscle mass as your genetics allow. You’re willing to do anything and everything to reach that goal in the shortest time possible. 

On the other hand, gaining muscle might be one of several goals you’re pursuing at the moment.

You don’t have the time or energy to give it everything, and you’re quite content with a slower rate of progress. You know it’s going to take longer to build the muscle you want, and you’re okay with that.

How often are you training? If your workout routine involves training twice per week, each training session is going to take longer than it would do on a 4, 5, or 6-day split where you’re hitting fewer muscle groups in each workout.

With six workouts per week, you might be able to get each training session done in 30 minutes. But with a 2-day split, each workout might take 90 minutes to get through.

In both cases, the total amount of training time, 180 minutes, is the same. It’s just being spread out differently across the week.

What type of training are you doing? Two people might do the exact same workout, but one uses paired sets. The other takes their time and rests for a couple of minutes between each set. That first person will get their workout done more quickly than the second, even though the muscle-building stimulus generated by both workouts will be roughly the same.

A strength training session that involves heavy weights, low reps and long rest periods will often take longer than a workout involving lighter weights, higher reps and shorter rest periods.

A powerlifter, for example, will typically perform compound exercises (squats, bench presses and deadlifts), train with low reps (1-5 reps per set), and rest for 3-5 minutes between sets.

A bodybuilder, on the other hand, using lighter weights, moderate reps (8-12 reps per set) and shorter interset rest periods (2 minutes) is probably going to be in and out of the gym in less time than the powerlifter.

But that doesn’t make one training session more or less effective than the other. They just serve different purposes.

How much stimulation do your muscles need to grow? When you’re just starting out, results are relatively easy to come by. Your muscles are highly responsive to any type of strength training, and don’t require as much work to make them grow. As a result, you can often get away with shorter workouts.

But over time, as your body adapts and you acquire more training experience, gaining size and strength becomes progressively more difficult. If you want to avoid remaining stuck at the same size you are right now, chances are you’ll need more work to keep the gains coming.

People also respond differently to different workout routines. Person A may need more work than person B to generate the same amount of muscle growth. As a result, they’ll need to spend longer in the gym.

In short, there’s no one-size-fits-all answer to the question of how long a workout should last.

There are so many ingredients going into the mix, from the training split you’re following, to your individual goals and preferences, to the amount of stimulation your muscles need to grow, that it’s impossible to say a workout should last X number of minutes.

Should You Limit the Length of Your Workouts to 45 Minutes?

However, this hasn’t stopped some trainers saying that there is an ideal workout length. In fact, you’ll often come across claims from the exercise police that you shouldn’t lift weights for more than 45 minutes.

If you do, testosterone levels will plummet, cortisol levels will rise and you’ll be sucked into a catabolic black hole from which you’ll never escape.

The idea that you should stop training after 45 minutes because you reach some kind of hormonal “tipping point” is one of the most ridiculous things I’ve ever heard.

It’s a claim that fails on a couple of levels, most notably the fact that it’s not true.

In fact, some workouts lasting more than 90 minutes have been shown to raise testosterone above resting levels for at least two hours after the workout has finished [2].

What’s more, the idea that the short-term hormonal response to training has a big impact on muscle growth is something that’s been called into question in recent years [1].

In one study on the subject, researchers analyzed data collected from 56 men who took part in a 12-week resistance training program [2].

If the post-exercise change in testosterone levels was important as far as building muscle is concerned, you’d expect to see two things.

• Guys with the largest post-training testosterone response would build the most muscle.
• Guys with the smallest post-training testosterone response would build the least muscle.

But when they looked at the data, the researchers could find no significant link between the exercise-induced rise in testosterone levels and gains in muscular size or strength.

RELATED: The Myth About Squats, Testosterone and Muscle Growth

What About Longer Workouts and Cortisol?

Cortisol is generally considered a “catabolic” hormone that you should take all possible steps to avoid.

If the post-exercise rise in cortisol was putting the brakes on muscle growth, you’d expect to see men with the largest rise in post-exercise cortisol gaining the least amount of muscle.

Instead, the opposite was true.

There was a weak but significant link between the rise in cortisol and gains in lean body mass, as well as the growth of the type II muscle fibers.

In other words, subjects with the biggest rise in cortisol levels were also the ones who gained the most muscle.

Drilling further down into the results, subjects in the study were also divided into responders (men who built the most muscle) and non-responders (those who built the least muscle).

And the hormonal responses of those who made the fastest gains in size and strength were not significantly different to those who made the slowest gains.

Or to put it another way, the hormonal response of subjects in the top 16% in terms of muscular gains were no different from those in the bottom 16%.

So why are people saying that 45-60 minutes is as long as your workout should last?

Where Did the Myth Get Started?

The idea seems to have originated with Bulgarian Olympic lifting coach Ivan Abadjiev. Over a 20-year period, Abadjiev turned a weightlifting team that struggled to win anything into one that won numerous European, World and Olympic titles.

Rather than train once a day for several hours at a time, the Bulgarians would train numerous times both in the morning and in the afternoon, with each training session lasting from 30 to 45 minutes.

The protocol was based on Abadjiev’s claim that elevated blood testosterone levels could only be maintained for between 30 and 60 minutes, with the average being 45 minutes.

Whether or not he actually believed this himself is hard to say.

Nicknamed “the Butcher” for the extreme level of dedication and commitment he demanded from his athletes, rumor has it that Abadjiev’s need for control was vast.

He once had a rebellious pupil sent to the military to work from dawn to dusk in a stone quarry.

Keeping them in the gym all day may have had a lot less to do with testosterone than it did with imposing discipline and control on his athletes.

Big Beyond Belief

Many of the principles employed by the Bulgarians were popularized in a book published in the early 1990’s called The Bulgarian Power Burst System. Later editions had different titles, such as Big Beyond Belief.

The book sold thousands of copies via its famous “I’ve got to get this off my chest before I explode” advertisement, and became one of the most successful self-published bodybuilding guides of all time.

It went on to influence a number of personal trainers, many of whom simply regurgitated the fictitious “testosterone levels drop after 45 minutes of lifting weights” advice before checking whether or not it was actually true.

That’s not to say you should be training for hours on end. Plenty of people are wasting much of their remaining time on this planet doing endless sets of pointless exercises.

But cutting your workout short simply because you’ve been in the gym for 45 minutes makes absolutely no sense at all.

Frequently Asked Questions

Is a 2-hour workout too long?

For most people, a 2-hour workout is far more than you need. However, there are instances where longer workouts can be beneficial. For example, if you’re an advanced lifter with multiple years of training experience, doing heavy strength work, resting for 3-5 minutes between sets, and training in a cold gym (which will necessitate a longer warm-up period), you may need a relatively long workout to get the job done.

What happens if you exercise too long?

In the short term, nothing much is going to happen, other than you feeling tired and sore for a few days. But in the long term, too much exercise will create a state of overreaching, where your performance in the gym takes a dive. While it’s uncommon, too much exercise can lead to something called overtraining syndrome, a state of fatigue, exhaustion, and depressed mood that can take months to recover from.

How long should your HIIT workouts be?

A HIIT workout, including warming up and cooling down, is going to take somewhere between 10 and 45 minutes. A bout of long interval training (i.e. 4×4 intervals) will typically take longer than a bout of sprint interval training, which can often be completed in a minimum of around 10 minutes.