Training in the gym usually falls to a secondary priority for most of our athletes when compared to work, family, etc. It’s an understandable prioritization. Work pays the bills, family time is wonderful, and the occasional happy hour is needed every now and then.
Somewhere inbetween those big blocks of time we schedule our training. For those who work a standard work-day schedule, that means ass early in the morning or right after leaving the work place.
We train when we can, not when it’s optimal. It’s understandable, but the differences in when we time our training are significant.
This article by Bayesian Bodybuilding provides an excellent overview of the literature on timing and training based on multiple studies of testosterone production, muscle growth result trials, and your sleep cycle.
Bottom Line Up Front (BLUF): The best time of the day to train is the window of 6 hours to 12 hours after waking from a complete sleep cycle. So if you falls asleep at midnight and wake at 8am (luck you), 2pm to 8pm is your optimized training time.
From a performance perspective, the increase in strength and/or endurance was negligible between morning and evening training in the studies cited below.
However, the prime example of the benefits of the evening training was in muscle size growth. The majority of the these studies found greater mass gains with evening training, and most of them were not structured strength programs but rather assessments of a certain kind of muscle-specific contraction.
Küüsmaa et al. (2016) studied the effectiveness a training program performed in the morning between 06:30 – 10:00 h or in the evening between 16:30 – 20:00 h for a 24 week period. While strength and endurance performance improved similarly across the groups, the men training in the evening gained notably more muscle mass: see the graph below.
In line with the increased muscle growth, muscle anabolic signalling after a workout is higher in the afternoon than in the morning
Laczo et al. also presented the following data at the 7th International Conference on Strength Training in 2010: more leg muscle growth after an afternoon training program than a morning one.
Malhotra et al. (2014) studied how training in the morning vs. the evening affected strength development. Strength gains were significantly greater in the evening for eccentric exercise: 29% vs. 23%. For concentric training, the trend was the same but less pronounced in favor of evening training with 23% vs. 21%.
Tim Scheett performed a study in bodybuilders on the best time to work out. Half of the participants trained before 10 AM in the morning, the other half after 6 PM in the evening. While the results never got published outside of the 2005 NSCA conference and didn’t reach statistical significance because of having only 16 participants in the study, look at the data below: the evening training group had much more favorable body composition changes.
Sedliak et al. (2009) studied trained men working out around either 8 AM in the morning or 6 PM in the evening. While again there were no statistically significant changes in strength development or muscle growth, look at the data of muscle growth. It’s likely the difference in muscle growth did not reach statistical significance because of insufficient statistical power, considering there were only 7 and 9 men in the training groups and the study only lasted 10 weeks.
Not all research shows benefits to training later. Sedliak et al. (2017) found similar anabolic signalling, hormonal effects, muscle growth and strength development in untrained men over the course of a training program performed either in the morning or the afternoon. However, with only 7 and 11 subjects in the 2 groups, this study was statistically underpowered to detect even a medium effect size. They couldn’t even find significant correlations between the different measures of muscle growth, so if there were benefits of training in the afternoon, as the other research suggests, they may well have been masked by the large variation in the data and this study simply wasn’t powered enough to detect it. Plus, the former study by these researchers only detected the effect after week 11, but this study was only 11 weeks in duration.
core body temperature
For those of you who train at different times of the day, you’ve probably noticed a signifiant difference in how you feel between a early morning session and a mid-afternoon session.
The morning feels slow. Joints creak to life and it’s far more challenging to get everything firing up quickly. This one hits close to home for me… my morning sessions need a lot more time to warm up and get ready to go, while my afternoons feel significantly better.
This is due to the natural rise of your body temperature throughout the day. Simply put, when your core temp is higher, your body is stronger, faster, and more flexible. This is what any warm up is designed to achieve, but as you can see by the graph below, the afternoon to evening time frame is ideal for natural core body temperature and exercise.
application of timing your training
The bottom line is for those of you who have hectic schedules, you train when you can. If that means 6am, so be it. I’d rather see you then than never. For whatever it’s worth, I’ve found that I do my best work after a good morning training session; my brain just seems to function better.
The additional benefit of morning training is that very few things will get in the way of morning training. No surprise appointments or dropping the kids at soccer practice. Just you, an alarm clock, and the barbell.
The science clearly support training in the afternoon-evening for the optimized performance and results, but getting in when you have no distractions is a powerful thing.