What is the best time of day to work out? I wouldn’t blame you if you were confused about this because everyone seems to have an opinion: Conventional wisdom says train in the morning to start your day right and improve compliance. Pas research has uncovered evidence that training in the late afternoon gives you the best results. In recent years, a number of training experts have claimed that neither of these times is ideal and that you should actually train at night. A recent analysis has shed some new light on the controversy.
It's all in your mind!
One thing we know for sure is that psychological and physiological functions can indeed change relative to the time of the solar day. These variations are known as circadian rhythms. It’s not a question of whether these rhythms exist – they do. The real questions are, how much does this affect your training performance and your results over time?
Several studies found that short-term maximal performance (sprinting, maximal muscle contractions, jumping, etc.) peaks in the late afternoon between 3% and 21%.
Why the difference in performance with different training times? One explanation is body temperature.
Exercise physiologists noticed that this rise in athletic performance in the late afternoon paralleled the circadian variation in body temperature (which also peaked in the late afternoon). They hypothesized that the increase in core temperature could have a passive warm-up effect, which enhances metabolic reactions, increases the extensibility of connective tissue, reduces muscle viscosity and increases the conduction velocity of action potentials.
Studies have also found that tendons are stiffer in the morning. Even the actual muscle architecture itself is different as the day goes on.
Certain exercises (involving bending and twisting) should be avoided within an hour of rising from bed. The discs are filled with fluid at that time, which magnifies the stresses placed on the spine.
Basically, most people are more likely to have used their muscles during the morning and day, whereas they are the cold and tight first thing the morning.
Hormonal response to training
Hormone levels can fluctuate based on the time of day. Testosterone and growth hormone are important for muscle growth and there is some evidence that testosterone rises more after a late afternoon training session than it does during a morning workout. The stress hormone, cortisol (which can be catabolic in nature), peaks in the morning and decreases later in the day.
Some experts have started recommending PM workouts for this reason alone – hormones. However, research is very mixed about how much these short-term hormone fluctuations affect performance, and more importantly, whether they affect long term results (strength, hypertrophy, etc.) at all.
The effect of training time on training type
Although differences have definitely been found in short term exercise performance, most studies have found that when training is prolonged, the differences disappear or are not significant. There’s little or no evidence that physiological responses fluctuate during the day during middle and long-duration performances which depend on the athlete’s vo2-max, HR max running/cycling economy.
So now that narrows our focus to something I am particularly interested in gaining strength and muscle! (This also applies to power training and intense or intermittent types of cardio training).
Ironically, the effect of weight training on strength and hypertrophy is the least studied area. Fortunately, that’s changing. Recent studies have not just stopped with measuring short term performance or acute spikes in hormones, they have begun measuring performance over time and adaptations over time.
If you are an athlete and you do your regular training at the same time of day that you usually compete (game time or meet time), you are more likely to perform better. In other words, if you compete in the morning, train in the morning. If you compete in the PM, train in the PM.
This also suggests that you avoid haphazard or random training times and be aware that if you switch your training time, there might be a decrement in performance at first until you get used to it – positively.
Many people find that training in the morning helps them stay consistent. One positive behaviour or accomplishment n the morning can set a positive tone for an entire day and your desire to stay on track remains high all day long. Some people also find that night time workouts are easier to blow off, because they are tired and stressed or work or family issues come up and take precedence (or, like some people I know, happy hour is calling).
Many people also find that if they train too late at night, it disrupts their sleep, and there is some research supporting this. That’s especially important considering that adequate quantity of sleep is one of the factors that affect diurnal variations in sports performance as well as body composition.
Customize your training time just like you customize every other part of your plan. The ideal time for you to work out is the same that a lot of common-sense trainers have been saying all along: simply train at the time when you can perform the best… when you feel the best physically… when you’re mentally aroused, alert and focused… and when you can stick with it.