In the National Sleep Foundation study referred to earlier, only 3% of late-day exercisers said they slept worse on days when they exercised, compared to days when they didn’t.
Furthermore, the NSF poll also reported on differences in self-assessed quality of sleep for different exercise times in the following groups:
- Exercise more than 4 hours before sleep
- Exercise within 4 hours of sleep
Of those people who exercised more than 4 hours before sleep, 81% reported fairly or very good overall sleep quality. This was 5% higher than those who exercised within four hours of bedtime. It’s important to note though, that both figures were very high.
Again though, the question asked wasn’t how exercisers slept after working out before bed compared to when they worked out in the morning – or other time of day. Four hours before bedtime might be around 6pm – which can hardly be considered before bedtime.
Also, there was no analysis of the type of exercise – cardio or weights – and how that might have affected sleep quality.
Unfortunately, this seems about par for the course.
There are some studies that look at the relative effectiveness of morning cardio and evening cardio but no comparisons with weight training.
One of the cardio studies from 2012 entitled, “The Effect of Training at a Specific Time of Day: A Review”, observes that training performances peak in the late afternoon.
This backs up other evidence that strength training later in the day is more beneficial than working out in the morning – because your body temperature is warmer and exercise is perceived to be easier. But again, nothing on the effects of a strength workout right before bed.
It goes on to suggest that regular aerobic training in the evening may enhance performance further. Again, no investigation into how regular aerobic workouts right before bed affected either performance or sleep.
As the New York Times article about Dr Baron (referred to above) dictates:
“It is impossible to yet know the sleep-related impacts of workouts of different types (like weight training), intensities or timing, including morning or late-evening sessions”.
Why? Well, it seems that the studies simply haven’t yet been done. That’s why trying to find them on Google may result in a wasted hour or two – I’ll save you the trouble.
Aerobic And Anaerobic Exercise
Quite apart from the lack of comparisons between cardio and strength training late at night before bed, there is even a distinct lack of research comparing the results of aerobic and anaerobic exercise on sleep full stop.
As we’ve seen, plenty of studies examine the correlation between sleep and exercise in general – and also the differences between the two types of exercise. But little else.
Some interesting insights could be gained by testing whether the type of exercise, aerobic or anaerobic, affects average nightly sleep differently?
It stands to reason that, if aerobic and anaerobic exercise benefit health in different ways, that they may also affect sleep in different ways.
Aerobic (cardiovascular) exercise pushes the entire body, working out many muscles and raising the heart rate; anaerobic exercise pushes only part of the body at a time, and the heart rate is not so dramatically affected.
It would be interesting to scientifically measure how this affects the restfulness of sleep.
Working Out Before Bed: How To Know If It’s Right For You…
In the absence of studies that have specifically tested the effects of aerobic exercise versus anaerobic exercise before bed, what can we do?
Like any curious individual looking for the best results, you can be the guinea-pig yourself. Test it out and see what works best for you.
To help with your experiment, I’ve put together some suggestions, and a tracking sheet, which you can download free below. Note that your starting point for any experiment will greatly depend on where you’re at presently with your workout routine.
If you’re an experienced, habitual, and vigorous exerciser, usually working out three or four times per week with cardio and weight-training, you can try my suggested workouts.
If you’re less experienced, adjust the experiment to match your current level.
It’s not exactly scientific, but after the three-week experiment, you should have excellent insight into how your own body reacts to working out before bed.
Pro-Tips: Finding The Ideal Gap When Working Out Right Before Bed
1. Noam Tamir, founder and program director of TS Fitness studio in New York, advises:
“Most people experience a drop in those stimulating hormones like cortisol and adrenaline within an hour or so after they work out, which puts your body in that relaxed, ready-to-sleep state.”
However, if a 45 or 60-minute break between exercise and sleep doesn’t work for you, repeat the experiment leaving bedtime until 90 minutes after your workout.
2. If you really want to start introducing night-time workouts into your routine and get the timing spot on, play with the times over an extended period and find out what works best.
3. Try using a personal activity monitor – this may help you understand how your sleep is impacted by exercising at different intervals before bedtime.
4. Need extra fuel? We all know that exercise eats up the nutrients you’ve taken in – but these reserves are further depleted during the night. You need a plan for nutritional recovery. Introduce a late-evening snack before your workout to ensure that you’ve got the energy to last the distance. And, of course, stay well hydrated, as water is lost during the night.
5. Try taking cool showers after working out at night, to help your body temperature return to normal quicker.
Another important point to bear in mind: do it enough and your body will adapt to your workout time, and prepare the muscles for action, be it morning, noon, or night.
By running these experiments with your workouts, you’ll almost certainly learn more about the type of exercise that your body reacts well (or not so well) to late at night before sleep.
And you may just be able to rule out (or rule in) working out before bed as an ongoing part of your daily routine.
Just Starting Out With Working Out?
Firstly, read “Beginner Workouts—From Swimming To Weight-Lifting” for some general tips on how to get started with a workout routine that’s right for you.
If you’ve decided that you want to give working out at night a go, apply the routine you’ve decided on but take it slowly. Start with ten minutes. And leave it a while before you go to bed afterwards: give yourself time enough to cool down, relax, and for body temperature, heart rate, and adrenaline/cortisol levels to return to normal.
Remember – even short, light workouts will stress your body at first, if you are not used to exercise.
Bottom Line: Should You Work Out Before Bed?
Those poor ‘fools’ you see working out through the 24-hour gym window when you’re on the way home from a big night out – are they really so foolish?
Just doing it is certainly better than not doing it but should we really be going to such extreme lengths to exercise?
Well, yes. It’s really that important.
For many people, fitting a workout into an already-hectic daily routine is a big challenge. If you’ve been following the same routine for years, it may be tough to change. And if there’s no compelling reason to change, why would you?
‘Horses for courses’
Whether you’re a ‘morning person’ or ‘evening person’ may be out of your hands – much of it is determined by genetics.
But some people choose working out in the morning to guarantee that the workout actually happens – before interruptions to the day take the opportunity away. Others believe that working out in the morning is the only way to commit to it in the long-term. And that’s OK.
Equally, if the thought of getting up at 6AM on a cold December morning and heading for the local gym has always filled you with dread, there’s no compelling reason to start doing that now; nor is there any reason why you should give up a lunchtime workout for a midnight one; but equally there’s probably no reason why you should replace working out before bed with an earlier session.
If you’re working out at night, you probably do so for a number of reasons: it may be the only available time in your schedule; it may be to overcome other temptations (like going out drinking?); it could be that the gym’s too busy at other times; you may have more energy at night; or it may simply be because you prefer running in the cool darkness of night-time.
Either way, the main takeaway is this: The best time to work out for most people is whenever you’re most likely to do it.
Exercise at any time of day is beneficial – and you’re more likely to commit to it if it fits in well with your lifestyle and you enjoy it. A convenient time helps with that – and if ‘convenient’ to you means midnight, so be it.
Work It Out For Yourself!
There is a lack of scientific evidence to compel you to change either the time you exercise or the nature of it.
Over to you Nike and Adidas. Perhaps it’s time to run the studies so that we’ll see new tag-lines in the future like Just do it…in the morning and Impossible is nothing … before bedtime!
Until then, I’d encourage you to experiment with cardio and weights to see what suits you best for working out before bed.
For some people, strenuous exercise before bed may delay sleep onset but the proof is in the pudding: test how it affects both getting to sleep, staying asleep, and overall quality of sleep.
Dr Stuart Quan, a professor of sleep medicine at Harvard Medical School warns: