Does when you strength train affect how much muscle you gain? You might prefer picking up those weights at a certain time of day because it’s more convenient, and it works with your schedule. If you’re a morning person, you might prefer strength training before work, while an afternoon or evening workout might be more appealing if you’re not fully awake until noon. Preference aside, how does that choice affect your potential to gain strength and muscle size?
To be successful with any strength training program, consistency matters most. You have to be committed, motivated, and not take too many days off from training. But what about the timing of when you train? Our bodies run on a 24-hour cycle set by our internal biological clock. Glands release hormones based on these cycles, so it’s not a stretch to say that you might make greater gains if you train at certain times of the day. What does science say about this?
There are two primary schools of thought regarding this subject: The “Afternoon Workout” and “Anytime Works Well” school of thought.
The Afternoon Workout is based on the belief that workouts you perform in the afternoon (between 3 PM to 6 PM) are most effective. Why? That’s when your body temperature is highest and your muscles most pliable and there is science to support this.
One study found that participants gained significantly more strength when they trained in the early evening as opposed to the morning. However, some studies show that strength gains are not affected by when you train. Nothing like conflicting results, right?
The Anytime Works Well advocates believe that workouts any time of day (morning, afternoon, or evening) are just as effective for strength increases, as long as you are dedicated and consistent with your training schedule. Proponents of this approach also believe that workouts done any time of the day don’t negatively affect muscle growth. Some research also supports this stance. So, which side has the most science behind it?
Your Body Temperature is Higher in the Evening
There are some physiological reasons to support both. Higher body temperature in the late afternoon and early evening makes it easier to lift weights, especially if you’re lifting heavy. Warm muscles are more flexible, and a higher body temperature improves blood flow to your muscles and slightly speeds up nerve conduction. So, it’s not surprising that you might be stronger in the evening than you are first thing in the morning.
The Role of Cortisol
Cortisol is a stress hormone that helps supply your muscles with glucose when they need it, but cortisol also causes muscle breakdown. Cortisol is highest when you first wake up in the morning and gradually decline throughout the day, reaching lowest levels in the evening. The stress of strength training also causes a rise in cortisol, so you’re getting an even stronger increase in cortisol.
Since cortisol causes muscle breakdown, training in the morning when cortisol levels are high might not be the best approach if you’re trying to maximize muscle gains. When you strength train in the later afternoon or evening, you get less of a boost in cortisol and if you train regularly, the increase in cortisol with an evening training session lessons. Not to mention, testosterone rises in the evening. So, your body is in more of an anabolic state in the evening as opposed to the morning.
The availability of carbohydrates for energy and protein your muscle need to repair also matters. If you do workouts first thing in the morning, you may limit your performance because your muscle glycogen stores are low. Your workout may feel harder, and you may not be able to do as many repetitions of lift as heavy due to low energy stores.
When you work out in the evening, you’ve had a few meals before you pick up the weights and that can improve your performance and give your muscle the protein it needs for repair.
Choose a Time that Works for You
If you’re serious about gaining muscle mass, a consistent training schedule and the right nutrients at the right time matters most. If you feel most disciplined in the morning, a morning workout might best meet your needs, but fuel up beforehand. By consuming carbohydrates, you’ll rebuild our muscle glycogen stores and by eating protein, you’re giving your muscles the amino acids they need to repair. Plus, carbohydrates help lower cortisol, a catabolic stress hormone. You’ll still be fighting a lower body temperature, so make sure you’re doing a thorough warm-up.
Also, think about what time of day you focus the best. If you’re most alert in the morning and your motivation and focus fade in the evening, morning strength training may work best for you, despite the physiological disadvantages.
Ultimately, it comes down to when you’re most mentally and physically primed to train. It might be helpful to train in the morning some days and the evening others while keeping a training diary. Note how you perform and how you feel before, during, and after. Keeping a training journal will help you fine-tune your workouts and discover the training time that works best for you.
If you train in the morning, pay attention to nutrition though. Doing an intense workout before breakfast when your muscles contain little glycogen can trigger muscle breakdown to supply amino acids to maintain glucose levels. When you combine this with a naturally higher cortisol level in the morning, doing intense strength training in a fasted state isn’t a recipe for success.
The Bottom Line
Find what works for you! An afternoon or evening workout has physiological advantages but, despite this, you may find a morning workout suits you best. The most important thing is to do it!
BetterHumans.pub. “The Best Time of Day to Hit the Gym May Surprise You”
Drust B, Waterhouse J, Atkinson G, Edwards B, Reilly T. Circadian rhythms in sports performance—an update. Chronobiology International. 2005;22(1):21-44. doi:10.1081/cbi-200041039.
LegionAthletics.com. “What’s the Best Time of Day to Lift Weights? What 35 Studies Say”
“Morning vs Evening workouts: which is better?.” menshealth.com/uk/building-muscle/a755788/morning-vs-evening-workouts-which-is-better/.
“Effects of morning versus evening combined strength and ….” pubmed.ncbi.nlm.nih.gov/27863207/.
“Effects of morning vs. evening combined strength and ….” pubmed.ncbi.nlm.nih.gov/30950283/.