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What’s the Best Time of Day to Workout to Gain Muscle?

May 2, 2018 • Jake Huddelston

“The road to Nowhere is paved with excuses.” – Mark Bell 

Before we answer this question, it’s important for you to answer a few questions yourself.

  1. How much of a priority is gaining mass, muscle, and strength to you?
  2. Are you willing and able to reorganize your schedule around this goal?
  3. Does your diet align with your goal of adding mass?

How much of a priority is it really?

All acts of self-improvement require sacrifice. Gaining muscle is no different and I would argue is one of the hardest things to accomplish if your body isn’t built for it. The argument has been made that gaining muscle is significantly more difficult than losing weight.

The good news is you can accomplish both of these at the same time, but we’ll save that for another day.

To gain lean muscle mass though, you’ll have to sacrifice your schedule, your way of eating, when you go to sleep, social activities, and you better be ready to buy some new clothes if you do this right.

I blew out three pairs of jeans within 6 months after packing on 25 lbs during my growth phase. In addition, my collared shirts looked like I picked them from my little nephew’s closet. Not a good look.

Point being, to be successful sacrifices will have to be made. If you really enjoy slow and steady cardio, sorry. You can pick that back up in 6 months. It’s time to grow.

Are you willing to adjust your day to this goal?

Suppose there is a “best time of day to workout” to peak your performance for muscle growth. Are you willing to adjust your schedule to lift at this time?

Are you willing to say no to a night out, or even to staying up later and watching a movie in? You need to catch your zzz’s. That’s where growth truly takes place.

How about your diet and the rest of your day?

It will hardly matter the 60 minutes you spend in the gym if you ruin it the other 23 hours of the day.

Your diet has to be on point. Your sleep has to be on point. You can’t give in to those extra treats and cheat meals like you normally would. You can’t reach for that nightcap anymore.

It’s time to be dedicated. And dedication is a 24/7 job.

The Best Time of Day to Workout to Gain Muscle

The great regulator: your circadian rhythm.

Your circadian rhythm determines which hormones are behind the wheel, your core body temperature, your reaction time and alertness, and flexibility. So to determine the best time of day to lift in order to gain muscle, we need to first dissect the above attributes and see how they correlate with our circadian rhythms.


The 3 key hormones to focus on for muscle growth are testosterone, growth hormone, and cortisol. The optimal environment for muscle growth is high testosterone, high growth hormone, and low cortisol.

Testosterone secretion is highest mid-morning, around 9:00 AM and then tends to drop throughout the day. This would lead one to believe this is the best time of day to workout to build muscle. However, it’s important to note, that this differs based on a variety of factors including your personal sleep cycle, daily activity, and nutrition.

Testosterone levels rise after exercise as well, especially after performing strength and hypertrophy sessions. This increase is more pronounced in the afternoon than in the morning, therefore balancing out working out in the morning versus the afternoon.

You can wait to lift too late in the day too. Once you get past the 7:00-8:00 PM your test levels are already winding down, and other hormones and factors can’t make up for the lack of natural testosterone.

So for testosterone: mid-morning or early afternoon win out.

Growth hormone also plays a significant role in muscle growth and adding size. GH tends to pulse throughout the night, with it peaking just before midnight (if you are asleep and in bed that is). You’ll get some smaller pulses in the early morning but that’s about it. More noteworthy, GH spikes post intense workout just like testosterone does.

However, research has shown that the time of day you exercise, plays no significant role in your GH secretion. Intense exercise elevates your GH levels, but it actually doesn’t matter what time of day this exercise takes place, just as long as it does.

Cortisol is secreted in response to stressors and acts as a catabolic agent, mobilizing protein. However, a normal curve for cortisol secretion is highest in the morning, roughly 8:00 AM, then dissipates throughout the day reaching it’s lowest point at 3:00 AM.

Note, depending on your work, home life, diet, sleep, etc. your cortisol level can remain elevated throughout the day and into the evening. It also acutely rises in response to physical stress, like intense training sessions.

All this to say, if we’re looking for a prime hormonal time to add mass, there’s really no sweet spot. Test and GH are highest in the morning, but so is cortisol. All three drop off as the day continues, but they all spike with an intense workout. What a mess…

Let’s take a look at some other factors.

Body Temperature

Body temperature corresponds to your natural circadian rhythm. Body temperature fluctuates throughout the day, reaching it’s lowest point at 4:00 AM and peaks around 6:00 PM.

Various factors will affect these times based on when you sleep, duration of your wakefulness, and even your metabolism. However, it’s important to note that your body temperature is independent of the environmental temperature, not accounting for any extreme circumstances of course.

A portion of your brain is activated by light and transforms that energy into neurological signals that set your internal temperature. This process is what actually controls your circadian rhythm.

So what does all that mean for training?

The higher your internal body temperature, the greater your muscle belly temperature. This lends itself to a higher rate of blood flow, oxygen utilization, and tendon elasticity.

A pretty strong case for the afternoon if you ask me.

Reaction Time & Alertness

Not only does body temperature dictate our circadian rhythm and hormones, but it also affects our alertness and reaction time.

The greater your internal body temperature, the greater your reaction time, alertness, and overall wakefulness.

All of this leads to the potential for greater performance in the gym.

*Bonus tip: increasing your external body temperature through the use of a sauna pre and post workout has been shown to increase the secretion of muscle building hormones like growth hormone, insulin-like growth factor, testosterone, and increases blood flow to flush waste products built up from your workout. Incorporate 10 minutes pre and post workout and you’ll notice a difference immediately.


Not only will you notice a difference in alertness and reaction time later in the afternoon, but your flexibility will naturally be greater.

This is due to the natural increase in body temperature, in addition to you being awake and moving around all day. You’re much more flexible after a day at work (unless you sit all day) compared to when you roll out of bed in the morning.

Flexibility corresponds to strength and size in the following ways: mobility is required travel through the full range of motion for the lift. For example, the back squat. The athlete that can reach 90-degrees versus the athlete that can only reach 45-degree depth is receiving a much greater stimulus for growth and therefore will receive a much greater reward for his movement.

Not to mention flexibility will stave off injury. However, there is the other side of the bell curve, as with all things. If you have too much flexibility and not enough strength for a movement, you can and will find yourself injured. Your ligaments will become loose, losing their elasticity, and be unable to contract as they should properly.


Is there a best time of day for gaining muscle, strength, and performance? Based on how circadian rhythm, body temperature, hormone levels, reaction times, alertness,  and flexibility correlate, one could argue that there is: roughly 4:00 – 6:00 PM. But it’s certainly not a strong one. 

The caveat being, that how much of difference does it make? Research is not absolute on the subject. If you switch your lifestyle to accommodate a 1-2% increase in muscle mass, was it worth it?

In fact, this study was conducted in December of 2017, and concludes “similar levels of muscle strength and hypertrophy could be achieved regardless of time of the day in previously untrained men.” Meaning that small changes in hormones do not affect muscle size and strength gains in any meaningful, significant way.

Even more, research has even shown that although there are some absolutes when looking at the above attributes, if you consistently work out at the same time each day, you will actually begin to perform your best at that time of day. In essence, you can set and reset your own circadian rhythm by when you habitually work out.

So work out when best suits your lifestyle and when you’re most motivated to go. The best workout plan is the one you stick to. If you’re looking to build mass, follow a rep scheme and volume that triggers that response, keep your diet in check, and take your sleep seriously. These will make more of a difference than if you lift at 6:00 AM or 4:00 PM.

Good luck.