People have their own favorite time to exercise. The morning people prefer to work out in the morning. While others prefer to exercise around the lunch hours. And some prefer to exercise sometimes in the afternoon. Finally, some prefer the evening workout.
But are there any downsides to working out in the evening hours. Some downsides include the evening workout interfering with social activities. While other downsides include the possibility that an evening workout may interfere with your ability to sleep.
A recommendation, that’s been around for a while, is to avoid strenuous workouts before bed. Seems like there are several reasons for this recommendation, including that the workout before bed:
However, people are not all affected the same way. For example, some couldn’t care less if they just came out of a High Intensity Interval Training (HIIT) workout. They may fall asleep as soon as they lay on the mattress.
Indeed, most people are able to fall asleep even after they exercise before bed. Especially relevant, a 2011 study reported that those who did 35 minutes of exercise before bed slept just as well as on those nights when they didn’t exercise.
In the meantime, the National Sleep Foundation in 2013 conducted a poll of about 1,000 people. And, the poll found that 83 percent of the people who exercised (at any time of the day, including evenings) slept better than those who didn’t exercise at all. In fact, only 3 percent of the late day exercisers said they slept worse on days when they exercised compared to days when they didn’t.
A 2013 Hokusho University in Japan study reported that vigorous exercise within one hour of bedtime resulted in participants taking an average 14 minutes longer to fall asleep. Especially relevant, the participants in the study were 12 healthy males. The study pointed out that vigorous exercise created a large physiologic excitement, likely due to release of adrenaline, delaying the start of sleep.
Next, the journal Sports Medicine reported, in February 2019, about a meta-analysis by researchers at ETH Zurich. In fact, the meta-analysis discovered that compared to people who didn’t exercise at all, people who exercised within four hours of going to bed showed no difference in the:
On the other hand, researchers found that exercise could actually improve sleep by increasing the percentage of time spent in slow-wave sleep, or deep sleep. In fact, study participants, who did some type of workout within four hours of bed, spent an average of 21.2 percent of the night in deep sleep. While those who didn’t exercise only spent an average of 19.9 percent of the night in deep sleep.
Especially relevant, the only exception to the above results were those doing HIIT. Seems like, vigorous exercise like HIIT, one hour before going to sleep can mess up sleep. And, this is because your heart rate goes very high during HIIT. Moreover, one hour just isn’t enough time for your heart rate to come back near its resting rate. Consequently, your body isn’t as relaxed and ready to fall and stay asleep.
Therefore, it’s necessary to limit the evening workouts to low or moderate intensity. In fact, researchers think that moderate intensity workouts, causes the parasympathetic nervous system to kick in. And, when that happens, your heart rate slows down which in turn, helps you relax.
Because people are different, each person has to try out the intensity of the workout before bed that will allow them to fall asleep after the workout.
A 2019 Australian study reported that 30 minutes of HIIT bike training had no effect on sleep. In addition, the HIIT session didn’t result in hunger pangs.
Above all, the study was based on only 11 middle-age men. Moreover, the study looked at how the men slept when they exercised in the morning (6 to 7 AM), afternoon (2 to 4 PM) and evening (7 to 9 PM).
Meanwhile, the study found sleep time was shortest when the men exercised in the morning. Next, the sleep time was the longest when the men exercised in the afternoon. Finally, the sleep time was somewhere in the middle when the men exercised in the evening.
In addition, there was only a one or two minute difference in the time to fall asleep between the morning, afternoon, and evening exercise sessions.
Next, researchers found reduced levels of the hunger hormone ghrelin when the men exercised in the evening.
Finally, the study reported that the men had more energy when they exercised in the afternoon or evening than when they exercised in the morning.
Research on hormones cortisol and testosterone indicates that weight training in the evening is best for building muscles. In fact, cortisol helps regulate blood sugar my breaking down muscle tissue (called catabolism) as needed. While testosterone, with the help of proteins, build muscles (called anabolism).
Cortisol levels are highest when you first get up in the morning and lowest in the evening. Similarly, testosterone levels are also highest in the morning and lowest in the evening. However, the ratio of testosterone to cortisol is highest in the evening. While both cortisol and testosterone levels dropped during the day, cortisol levels dropped more than testosterone levels. As a result, the evening provides a more anabolic, muscle-building environment for weight training. In fact, according to Applied Physiology, Nutrition, and Metabolism, anaerobic capacity is 7 percent higher in the evening when compared to morning. For this reason, early evening gym sessions are preferred by weight trainers.
Furthermore, temperature peaks in late afternoon. And research shows that muscle strength also peaks in the afternoon almost in sync with temperature. Moreover a 2005 study found that optimum performance is towards the end of the afternoon and early evening when the body temperature is also at its peak. In fact, a study found that those who weight trained after 6 PM in the evening gained 3 percent muscles while losing 4 percent body fat.
Finally, it is recommended that a carbs and protein post-workout meal be eaten within 45 minutes after the end of the weight training workout. Indeed a delay of carb consumption by as much as two hours may result in 50 percent lower rates of glycogen synthesis. On the other hand, you could eat the meal before the weight training session.
In conclusion, vigorous exercise such as HIIT workouts pumps out adrenaline, just before bedtime, which may delay start of sleep. However, light or moderate intensity workout before bed likely will have minimal, if any, impact on your sleep. However, because of individual differences, the best way to determine if a workout before sleep works for you, is to experiment.
Meanwhile, if you are under stress before bedtime, a vigorous workout before bed is the best thing to release all that stress, clear the mind and help you sleep.