Is there an optimal time for training? The answer is “yes, no, and actually…it depends.”
Yes, there is substantial research-based evidence to suggest that certain types of exercise or training, for specific or unique individuals, is indeed best performed at a particular time of day. No, there isn’t really one perfect time for training and in fact the time you have available to fit your exercise in and get it done may well be the ideal window. But all this depends upon a wide variety of contextual factors.
We want the right amount of exercise to be additive, and not detractive, to our lives. Sacrificing sleep to get up extra early and put in a workout is potentially unwise. Feeling stressed or rushed when trying to get some exercise into your lunch break may be counterproductive. Beating yourself up when you can’t train at your usual time, or even can’t fit a workout in on a particular day, are unnecessary forms of self-loathing.
Good overall health, high fitness, and peak performance can be viewed in two distinct ways. In the first way, these items exist on a continuum or in a pyramidal fashion, with health being the necessary foundation for fitness and performance being preceded by the first two and dependent upon their presence. But the amount of exercise required for health is generally less than that needed for high fitness, and the training volume necessary to attain peak performance is higher still. So it’s entirely plausible that when we exercise for basic health may not be quite as critical as when we are trying to time training for high performance.
The other way we should view the reasons we work out (health, fitness, performance) is from the perspective that they are equally important and totally capable of harmonious coexistence. This is no easy feat to achieve. Overtraining, or more appropriately not training intelligently, can result in illness, injury, and burnout. One has to be a true training maestro (or have a killer coach) to get and stay healthy and fit while nailing peak performances. But it can be done.
So getting back to time of day…the single best time you should exercise is when you can make it happen. But — and this is a big butt — you must be sure to assess your recovery status and progress and to modify your programming to fit life’s many circumstances (including those that are unpredictable). Training is a stressor. It just happens to be one that we can control. Let your workouts flex and flow as they must in response to the stresses (weather, work and family demands, etc.) you can’t control. Train when you can and make the best of the time you get.
Having stated the above, now I’ll suggest that most human bodies respond well to training that is on a regular schedule. The body has the ability to adapt and optimize when it knows that a training stressor is going to appear in a regular, predictable timeframe. It’s OK to have exceptions but if your usual workout time is fairly regular, studies do show that your injury risk goes down as your workload capacity goes up. This is even more true when you align the type of exercise you do with its demands and your circadian rhythm.
Exercising in the morning has a number of great things going for it. Workouts in the a.m. allow the body to train in a fasted state, which can enhance certain aspects of metabolic function and fat utilization, if that is one’s goal. It also tends to be very well-aligned with low-intensity steady-state (LISS) exercises such as walking, jogging, swimming, cycling, etc. as these modes of training tend to allow the body to warm up gradually and they present a relatively low overall workout stress load (as long as the intensity is kept at a lower level).
But no matter how thorough your warmup, training in the morning is invariably done with a body possessing lower core temperature, and stiffer joints, muscles, ligaments, tendons, and blood vessels. You can do any kind of training you desire in the morning, but when performing more intense exercise, be sure to use a very progressive warmup and embrace a scientifically-proven output capacity that is a few percentage points lower than what your potential would be in the afternoon.
Speaking of p.m. training, it’s in the middle to late afternoon when our bodies are most receptive to high intensity training which might include intervals, sprints, heavy resistance training/weight lifting, and other practices. This is because as core temperature peaks, we experience better tissue extensibility, higher strength/speed, and faster reaction times, to name a few benefits. The message here is that “Gitting After It!” may be slightly safer and more effective when more explosive training is conducted in the afternoon or early evening.
Circadian rhythm is an interesting subject and one that is currently heavily studied and debated. There may be two major peaks in rhythm in the day, a morning and an afternoon wave. Or there may be a major and a minor. It really does depend on the person. And there may be a pairing of one’s cognitive and physical peak periods. Or, if you are like me, those two might function somewhat separately. To be specific, I’m a cognitive crusher in the morning, getting the bulk of my concentration-based work done before lunch. But I’m a p.m. powermonster when it comes to workouts. I feel better and perform higher when I train in the afternoon or evening. Your mileage may vary. I encourage you to experiment and find your best training time. Cheers!
For more insight into this topic, check out this week’s podcast.