There are lots of myths surrounding what’s good or bad for you in relation to getting a better night’s sleep. One long-held view is that strenuous exercising before bed will keep you awake.
Recent research, however, has cast doubt on this view – at least for the vast majority of people. Researchers have in fact shown that any exercise during the day, regardless of the time, could improve your sleep.
In this article I’ll be taking a closer look at the evidence for the effects of exercise both during the day and just before bedtime. So if you’re fond of late night runs or gym sessions, but also worry about insomnia, hopefully you’ll find the advice here useful.
Why late exercise wasn’t advised in the past
Previously, the general advice about avoiding intense exercise just before you go to bed was based on three key factors:
- Exercise raises your body temperature. This counteracts your internal body clock,which lowers your temperature before bed.
- It releases chemicals in the body and brain, including adrenaline, which may stop you falling asleep.
- A high energy workout might make it difficult for you to relax and calm down, something important for sleep. Although for many people a burst of exercise can be the perfect stress buster.
Recent research findings
In 2013 the National Sleep Foundation (NSF) conducted a poll of 1000 adults between the ages of 23 and 60. They asked a large number of questions about exercise levels and times as well as the effect on sleep.
An interesting outcome was the percentage of people who reported they had a fairly good or very good quality of sleep as a result of different levels of exercise:
- 86% of people who did vigorous exercise had fairly good or very good sleep quality.
- 77% of people who did moderate exercise.
- 76% of people who did light exercise.
- 56% of people who did no exercise.
You can see in the chart below that there’s a very marked difference between no exercise and any level of exercise.
In the introduction to the NSF poll they define the two types of exercise with these examples:
- Vigorous exercise involves physical activities such as running, cycling or swimming.
- Moderate exercise involves more effort than normal, such as yoga, tai-chi or weight-lifting.
These are of course only guides, as weight-lifting for example can be very vigorous. There was little difference in the length of sleep that people said they thought they got, regardless of the amount of exercise.
So it would appear that the positive effect is more about the quality of the sleep, rather than the length or how long it takes you to fall asleep.
Other sleep implications
The NSF poll also reported other fascinating findings related to sleep. For example, it was found that people who don’t exercise are more likely to take medicine to help them sleep:
- 17% of people who did vigorous exercise also took medication.
- 19% of people who did moderate exercise.
- 21% of people who did light exercise.
- 34% of people who did no exercise.
It’s important to note though that the poll didn’t explore whether people who didn’t exercise had an underlying medical condition which stopped them exercising.
In addition to this the research also identified that people who exercised and slept better felt more alert and positive the next day.
What about exercise before bedtime?
The NSF also looked at the reported differences in quality of sleep for different exercise times in two bands; more than 4 hours before sleep, and within 4 hours of sleep.
The table below shows some of their key findings. There’s a small difference of 5% between those who exercised earlier compared to those who exercised within 4 hours of bedtime.
|Vigorous or moderate exercise within 4 hours of bedtime||Vigorous or moderate exercise more than 4 hours of bedtime|
|OVERALL SLEEP QUALITY|
|% of people reporting fairly or very good overall sleep||76%||81%|
|QUALITY OF SLEEP ON EXERCISE DAYS|
|% of people reporting that quality of sleep improves – compared to non exercise days||55%||54%|
|LENGTH OF SLEEP ON EXERCISE DAYS|
|% of people reporting that length of sleep improves – compared to non exercise days||33%||29%|
Note that all the people questioned reported improvements in quality and length of sleep on exercise days, regardless of when they undertook the exercise.
A number of articles in the press picked up on this NSF poll and suggested that any exercise before bedtime is okay for getting a good night’s sleep.
It could be argued though that the 4 hour band is too broad. For example, it doesn’t really cover the case where someone hits the Gym for a high intensity workout before going straight home to bed.
In 2013 two researchers from the School of Lifelong Sport, Hokusho University, Japan conducted a study involving 12 healthy males who undertook vigorous exercise about 60 minutes before bedtime.
They found that on average vigorous exercise resulted in the participants taking an average of 14 minutes longer to fall asleep, compared to non-exercise days.
The researchers reported:
These results indicate that pre-sleep vigorous exercise, which causes a large physiologic excitement at bedtime, might disrupt the onset of sleep.
What about less strenuous exercise?
Some forms of less vigorous exercise may well be helpful, even immediately before bed. For example, a low intensity yoga, tai-chi or stretching session are often recommended as perfect activities to do before sleeping.
This is because they can help you to unwind, clear the mind and relax before bed. Not because they might tire you out in the way that exercise does.
So is exercising before bed bad or not?
More research is probably needed to decisively answer the question of whether or not exercising before bed is bad. And a lot will also come down to personal choice and how you react to exercise.
At this stage my personal understanding would be:
- It’s very clear that any exercise during the day should help you sleep better and feel more refreshed the next day.
- Exercise close to your bedtime will, for most people, be fine and shouldn’t interfere with your sleep.
- It’s probably best to avoid vigorous exercise in the last hour before your bedtime.
And if you’re still confused and want the flexibility to exercise right up until bedtime, then perhaps you could experiment for yourself.
You could try spending a week doing your chosen exercise a few hours before bed. Then the next week you could try doing your exercise about 1 hour before going to bed.
You should be able to decide for yourself if you can exercise before bed or not, and if you need to leave a time gap between exercising and trying to sleep.
If you already have a personal activity monitor which also measures sleep, then you could use that to help you decide if your sleep is improving or being disrupted by exercising at different time.
If you have no option but to exercise right before bedtime, then there are some well-known measures you might want to try to see if they help you:
- Take time at the end for a cool down exercise period, letting your breathing and heart rate gradually return to normal.
- Take a short cool or even cold shower to help get your body temperature down.
- Make sure you re-hydrate, as research has shown that water plays a key role in good sleep.
- Consider trying some relaxation techniques before going to bed, which will also help to bring your adrenaline levels down.
I’m interested to hear your views and experiences, especially if you do vigorous exercise in the hour before bedtime. Does it delay you sleeping or have an effect on the quality of your sleep? Or do you find exercises helps you sleep, no matter when you do it?