The Best Time To Exercise

just a little bit neurotic, will routinely ask “what’s the best time to exercise?” This may seem a tad bit silly, but believe it or not, there have been many studies conducted with each trying to “prove” certain times of the day may provide better results than others. For example, the American Council on Exercise completed a study which seemed to show that exercisers who worked out right after waking seemed to be slightly more consistent and regular with their routine.

But is this just splitting hairs? Does it really matter when you exercise? Shouldn’t performing some kind of exercise on a regular basis be all you need? This is what common sense seems to tell us, but there are many conflicting studies – per usual – in the scientific world. For example, did you know that exercising in the mid-afternoon may help to “reset” your internal body clock?

Let The Controversy Begin

Other sources conflict with this idea, stating that it ultimately does not matter what time of day you exercise. Other sources state that working out at night may help to keep you awake longer. And yet, other sources conflict directly with this advice. Confused yet? I thought so. When we look at the big picture, exercising regularly should be all that matters. Most Americans don’t get enough activity as it is. The best advice to give, generally, is to get some sort of exercise on a regular basis. Nonetheless, for those with specific guidelines, goals, or a genuine scientific interest – does the time of day actually make a difference?

One interesting study looked at cortisol and growth hormone responses to exercise at different times of the day. They found that exercise at 7AM resulted in a much larger cortisol response compared to exercising at 7PM. The growth hormone response did not seem to matter, meaning that in the end, the only factor affected by exercise timing was cortisol response.


Since cortisol is important for a variety of reasons, this information may prove useful to some folks out there. If you are an elite or competitive athlete, it may make a small difference, to work out at certain times and not others. In one study, researchers looked at body temperature and time of day. They found that if methods were undertaken to raise body temperature in the morning, better results may follow. This is due to the circadian low that most of us feel in the morning, which could hamper performance.

In another study, the authors looked at anaerobic exercise compared with aerobic exercise. Ultimately, they seemed to conclude that performing exercise at the same time every day, seemed to matter the most. More confusion. Another study showed that your internal circadian rhythm is the best determinant of when you should exercise.

To further complicate matters, some studies have looked at body temperature, and how it may relate to exercise. Another study showed that the only difference time of day made, was dependent on how fast your muscles were moving. Some evidence shows that reaction time is best in the afternoon, and blood pressure and heart rate are the lowest. This means that performance in the afternoon may be at its peak, at least in some athletes.

Information Overload

If you’re overwhelmed or confused by this information, you’re not alone. As you might expect, this overwhelming amount of muddy and somewhat conflicting information results in anything but a definitive answer as to what time of day you should be exercising. I’d venture to bet that the slight advantages you may see by exercising at specific times of the day, will be offset by a less-than-ideal eating and sleeping schedule, not to mention any missed gym visits or alcoholic indulgences.

Internal Body Clock

Are you an early bird or a night owl? Working out when it’s best for you, may be the best idea. Many studies actually back up this idea. And yet, other studies seem to show that fasted exercising may be ideal. I’ve seen this question countless times while training clients – “should I eat breakfast before I work out or after?” This is not really a huge concern, but many clients expect there to be some “magical” answer. Unfortunately, that’s how the world works, and there is no “one size fits all” approach.

In the world in which we live, there is too much information for any one of us to come close to process everything we see in a day. Perhaps it is this abundance of information, this overwhelming constant stream of details and opinions that lead many to seek a clear, clean cut, “never have to think about it again” answer. But when it comes to exercise, there is never “one” answer.

Fasted Exercise?

The New York Times has even gone so far as to say that fasted training in the morning may be better for weight loss. They reference a study from 2010, which may back up that claim. But in a nation of people who are sitting too much, eating too much, and are generally very unhealthy, should we really be worried about the minute details of exactly when to exercise? It doesn’t seem very logical.

More than one-third of the United States is obese. Not overweight, but obese. The annual medical cost of obesity is around $145 billion. Think about that for a minute. These are staggering amounts and numbers. This translates to over 78 million obese adults in the United States. To combat all this obesity, we need to be worried more about getting them to eat well and exercise on a regular basis, rather than exercising at 7AM vs 7PM.

Elite Athletes

But back to our earlier example of an athlete, who may need that 5% boost in their performance. A good write-up by the Huffington Post seems to provide some evidence for multiple ideal times of day – each providing their own unique benefits. In one example, they even claim that exercising first thing in the morning will help you sleep better at night.

In another example, they state that exercising in the late afternoon will help you get stronger. And in a third example, they state that weight loss is best achieved by working out early in the morning. What to make of all these findings? Not much, by my estimation. Again, these are reliant on specific studies, not backed up by other studies, and are limited in results and scope. I must ask, would one honestly believe that those of us in great shape, or those of us who are very strong, are simply this way because of the time of day when we perform our workouts? Clearly this can’t be the case.


In closing, it may make sense to alter your workout schedule, if you are really struggling to maintain weight loss, or feel you are getting less than optimal results. But this is because you may have other issues to deal with. Maybe you’re naturally a night owl. Or maybe you are stressed from your job, and it makes more sense for you to exercise first thing in the morning, when you have more energy and are less stressed.

And perhaps more than anything, it matters what your diet is like. You can work out three times per day, 8 days a week, and it won’t matter a bit if your diet is poor. Does this make sense? It should. A nutrient-dense diet, with lots of vegetables, quality sources of protein, and healthy fats will be far more beneficial to you than working out an hour earlier or later.

“But my friend has a six pack, and she works out every morning!” Well, this is for a few reasons. One, she may be genetically predisposed to carry lower levels of bodyfat. Two, I bet her diet is pretty nutritionally strong and very healthy. Three, it is more likely her regularity of exercise – rather than the exact timing – that is giving her great results.

In the end, it is these factors that ultimately matter, much more so than what time you head into the gym. I know some people may think otherwise, but it’s ultimately true. Exercising on a regular basis is no doubt a positive thing, but obsessing about the details can be counterproductive. So, in a situation such as this, one must ask themselves: why am I concerned with the question to begin with?

Are you simply looking to get healthier, or are you using this exacting system of control as something else entirely? Many in the health world are a bit too obsessive about exercise and nutrition, and this can ironically result in poor health. “Paralysis by analysis” is one way to put it, and it is more common than you may realize. So remember: just exercise regularly, and don’t worry too much about the exact timing of the session. The regularity of your exercise and a healthy diet are really what will result in long term health.

This article originally appeared on PaleoHacks.