Exercise before bed is linked with disrupted sleep | Hacker News Reader

Exercise before bed is linked with disrupted sleep

medicalxpress.com

110 pointsPaulHoule76 comments

Note that the comparator here is "exercise before bed compared with doing the same amount and intensity of exercise earlier in the day" -- NOT "exercise before bed compared with doing no exercise at all."

Actual RCT findings (e.g. [1]) find that exercise does induce beneficial changes in sleep, compared against not exercising at all.

[1] https://www.frontiersin.org/journals/psychiatry/articles/10....

Purely anecdotal of course, but as a person that struggles to do sports consistently: for me, the thing you are saying this does not prove is absolutely correct. As far as my body is concerned, not doing any sports for months will get me way better sleep then when I do any amount of exercise after 6pm.

As a matter of fact, if I do exercise (cardio) that late, I can guarantee that I will not be able to fall asleep before 1-3 am. Even if I do it consistently for a few weeks.

Obviously just an observation of my own body. But it's the reason why I will no longer even attempt to do anything remotely like cardio post 4pm

I've found that this is true for not cardio workouts like climbing as well. It's truly unfortunate since that's typically when I have time, but staying awake until 2 isn't worth it.

Anecdotal support incoming: I work out twice a day, 15-20 minutes of lifting in the morning and 15-20 minutes of exercise bike in the afternoon. Have done for about the last 2 years. I also can't exercise after about 8 (I typically lay down for bed at midnight or so) or I'm up all night. I'm thinking that there might just be some sort of something in bodies where physical exertion induces a physical exertion mode to operate in that precludes sleep for a while. It kinda tracks in an evolutionary biology sort of way (despite that field being speculative an untestable): we didn't used to exercise. We used to exert ourselves when we needed to to stay alive and just sort of hang out and rest when we could get away with it. Having two modes, one that says "We're safe and comfortable and can lose consciousness for a few hours now" and another that says "Idk what we're doing but we're doing something and need to not fall asleep for a bit" has pretty obvious advantages compared to a system that allows you to take a nap in the middle of climbing a tree to avoid a predator.

More anecdotal data. I’m not a morning person by any stretch, but after decades of training on the evenings I switched to morning workouts where I wake up at 4am to get to the gym I’ve founf that I have less sleep interruptions, now I don’t if it it was due to all the water intake before or that now when I finally hit the bed I’m already exhausted.

often-enough after a meal, I feel an impulse to walk a little bit, and I do. I live in a 5-floor building with roof access, thus six total flights of stairs.

I find myself walking down from my middle floor level to the first floor, then to the top, and then the bottom, and the top again, often enough, after a meal.

My body contains 4.5 liters of blood and I sometimes imagine pumping it a few times through my system to help the rest of my body process the meal.

This is especially true if the meal was carby/sugary. Instead of lying there motionless and making my insulin do all the work of bringing my blood sugar back to normal, I imagine myself "pumping" the sugary blood through something that is happy enough to do something with the sugar (your/my muscles, as walking up 12 flights of stairs obviously accomplishes).

I am on the margins "athletic", but some days find myself at the end of a pretty sedentary day.

I _always_ am thrilled to have a single airpod in and listen to a book while meandering 12 flights of stairs, even if it's late, like, midnight. I've 100% done that a few times, and i find it helps me sleep well. Maybe the lack of exercise + insulin spike + no muscle activity usage of blood sugar would disrupt my sleep more than having pumped the sugary blood through muscles a few times.

I quite like this for me. I've lived in this building longer than I've made use of the convenience of walking up these flights of stairs. Some days I do 40+ flights of stairs!!! Even I am impressed. But doing them simply a few times a day, two or three trips. 12-18 flights at a time. Adds up quickly, obviously.

isn't it unhealthy to exercise after meals?

Depends a lot on the person and what they've just eaten and how they're exerting themselves.

Light to moderate activity to help keep glucose levels flat-ish is almost certainly a net positive.

This is sad to hear, <= 4 hours before bed is the only window of my day for exercise. I can make an effort for the morning but I would need to radically rearrange my life.

Since it says "linked", there may be exceptions, every body is different.

> <= 4 hours before bed is the only window of my day for exercise.

Same. Son and I walk 3-5mi at night. Upper 80s and 90% humidity is preferable to daytime. Many fewer opportunities to be mowed down is a plus.

FWIW: I had insomnia for years before eve exercising. Sleep is improved, some.

Sample of one, but I find gentle exercise in evening (like walking) isn't a problem. A moderate-to-intense run in the evening does affect my sleep, though.

> gentle exercise in evening (like walking)

I don't disagree with this but even walking 4mph @ 87°dewpoint = ⅔ soaked, which feels not gentle. Actual intense exercise in that mug might kill us however.

>A moderate-to-intense run in the evening does affect my sleep, though.

Oddly, I've used short strenuous workouts to combat severe insomnia. More pain is better. It helps when panic is the driver but not for sleep=broken events.

That’s fair, I didn’t think about climates actively hostile to “gentle” exercise :)

I know a lot of people who work out during their 2H lunch break because they don't have the time otherwise.

If you can't take that 2H lunch break consider if you're being treated like a slave.

There is another problem here: eating and working out doesn't go together well.

You workout before you eat. Here. Solved.

So not taking a 2-hour lunch is equivalent of being mutilated, starved, raped, humiliated, dismembered, killed with impunity?

I think your values are a little off...

Straw man. yes I would call it modern slavery.

Slavery still exists, so you need another name, like maybe "hourly employee".

E.g.,

https://www.ryanjhite.com/2024/09/23/mauritanias-hidden-hist...

No need, wage slavery is an already established term

https://en.wikipedia.org/wiki/Wage_slavery?wprov=sfla1

The options here are to either exercise on an empty stomach or to exercise right after eating. Both are frankly garbage options.

Eat breakfast.

That misses the point here. You roughly have your lunch break when your body is close to done with breakfast.

Excuses

Unless you suffer from disrupted sleep, there would not seem to be any reason to change your regime.

It might be that exercise right as you get up in the morning might have 100% roi if you sleep better that night. (meaning 30 minutes of morning exercise might overcome 30 minutes less sleep but more efficient sleep)

Check the charts friend, it mostly applies to maximum intensity exercise.

If you’re jogging or weight lifting you have absolutely no risk. You’d have to reach 90-100 HR for a quite a long time to actually be affected.

From the diagrams it seems only the maximal level of exercise strain is significantly affecting sleep.

> Exercise strain was quantified using summated-heart-rate-zones scores (SHRZS).

Aerobic exercises at maximal level are not every day thing and by themselves do require up to 72 hours of recovery. Even for elite athletes it would be maximum once or trice per week, depending on the mesocycle.

> The present study had limitations that should be considered. [...] The summated-heart-rate-zones score (SHRZS) method for quantifying exercise strain may underestimate the relative metabolic strain of strength training that involves very brief durations of high-effort movements. Future research could examine the effects of different types of evening strength training (e.g., Olympic lifting).

For weightlifting volume (number of sets) and intensity (weight attempted) of the exercise combined with maximum HR would be a better measure.

> We were unable to control for potential confounds known to impact sleep, such as bright light exposure.

In my experience, at the end of preparatory phase (at the maximum stress) any light leaking into bedroom will make it difficult to fall asleep.

HIIT does that though. Literally pushing the heart rate. I do that twice a week, so this is annoying

I figured out in high school/secondary school that doing strenuous exercise within a few hours of bed time would kill my chance at a decent sleep. I have always found it easy enough to do formal workouts in the late afternoon or early evening.

What gets me sometimes though is the "unexpected" exercise. A few months ago, while on vacation, I decided to climb the 10 flights of stairs up to my room, not wanting to deal with the slow and crowded elevator. 4 hours later, it's 2:00 AM and my mind is racing and it's like "why can't I sleep, that was a long day!". The next morning I remembered my trek upstairs and reminded myself that anything which elevates the heart rate is best avoided before sleep.

i'd consider it alarming if 10 flights is already "exercise" or even noticeable

timing can be a pretty big thing. Do you go up stairs slowly, or quickly? One step at a time or two?

If someone is hustling up a staircase, the output can be quite high, even at the level of the 3rd floor. I notice myself, sometimes, forgetting something and moving quickly in and out of my 3rd floor apartment by stairs, and I'll notice myself breathing hard after just the 3rd floor.

And sometimes I hike the building (6 floors) twice or three times, because it feels nice, and everything is timing. One can get easily get a high-intensity, short-interval fairly-involved full-body effort out of ten flights of stairs.

I note a part of me that wants to be defensive wants to say "or perhaps someone else does not know how to try hard enough to make ten flights a good workout?"

Something about your comment feels dismissive, and this random passer-by didn't like it, but I could certainly be projecting, etc etc.

That's the thing. It was not noticeable at the time. No heavy breathing, no pain in the legs, no sensation of "this is hard" that you get with most formal workouts. But I have no doubt that my heart rate and adrenaline/cortisol levels had already been elevated, enough so to disrupt the typical sleep cycle.

This became more of an issue when I got older. I used to run in the evenings and get away with it. Now in my 40s, I have to run in the morning. If I run at night, I wake up feeling tired and not well rested.

Same hear, in my 40s, except I've recently picked up wrestling (freestyle). On the nights I train my sleep is atrocious. I've been putting it down to being old and out of shape, but it might also be the 1930--2100 timeframe.

> I've recently picked up wrestling (freestyle)

Do you have a specialized wrestling gym or something like that near you? I've never heard of such in my area so I'm intrigued.

No. Just a local gym with mats. Started taking my son and thought it looked like fun so started doing the adult class. So far I've learn a lot whilst losing every match I do.

I'm really weird when it comes to exercise it seems... Doing intense exercise right before bed gets me into a really relaxed state and I fall asleep quickly. Like, doing push-ups and sit-ups for 10 minutes straight.

I don't run that often anymore, maybe twice a month, but I can only do it in the afternoon or evening. If I go in the morning, I feel very tired so I really have to force myself to keep going, and then after 15-20 minutes, my heart rate settles at close to 190bpm (compared to ~175 in the evening) which to my understanding is way too high for someone in their early 40s.

I used to be like this back when I chronically under-exercised, it was the only thing that would help me sleep. And even then, I struggled with insomnia.

Personally I need 10-20 hours of real sport a week to function really well, which seems to put me in some very high percentiles on HN. I need so much sport that I barely have time to do anything besides work and exercise, which means I don't do many non-athletic hobbies anymore.

> More strenuous workouts closer to bedtime coincided with greater disruptions to sleep and nighttime cardiac activity.

My wife wants to know what kind of "strenuous workouts closer to bedtime" exactly are alluded to here?

Duration of the activity might be a factor here.

Given the challenges involved in replication of studies like these, I certainly wouldn't let this one example change your established routines.

“Honey, we’re in the test group for the RTC!”

Prescient timing, went for a 10pm workout last night and was up until 2:30am wide eyed in bed unable to sleep. I feel like I need to try this every couple years to be reminded how it affects my sleep.

When I have to do an evening workout I have two options: insomnia or drugs.

Specifically 1.5mg of melatonin and 25mg of hydroxyzine an hour before bed, knocks me out every time.

I believe it to be somewhat true.

Back when I trained hard on morning, nap then exercise again during the evening, I noticed my resting heart rate would be quite high after the exercise, something like 70 when it’s under 50 normally and stay like that for around 4 to 5 hours.

On the other hand, it never prevented me from napping. Quite the opposite, so I’m surprised it has such a dramatic impact on sleep quality.

ItIt could be linked to cortisol tho, increase cortisol high enough and even though you’re not fully rested you can’t sleep anymore and feel like shit.

So you sleep a little, recover barely enough but too stressed to recover 100%.

I don't know, maybe it just me but I feel like I get some pretty good sleep after "exercising" with my boyfriend..

I've anecdotally experienced this as well.

Fwiw, I used to believe that it would be entirely impossible for me to work out in the mornings, but I have managed to make it work, despite generally having had a preference for waking up later. It is doable with some effort, don't get discouraged.

I also switched to early-bird and working out after many years of being a night owl. I even had a DNA test that told me night owl was my preference!

Going to sleep early (9pm), and setting my alarm across the room has been the key for me. It can be done!

Having an alarm is really bad for your heart

Would you mind to elaborate, pretty please?

Anecdotally, I feel way more refreshed when waking up without an alarm, and the times vary a lot; it seems sometimes, not a very long sleep is needed to wake up naturally and other times one needs more of it. But any artifical disruption feels "wrong", not just unpleasant but "messing with nature".

My gut instinct suggests NOT to violate one's chronobiology, so I'm not even going to aspire that.

Interestingly, I always sleep like a dead log after a weight lifting session before sleep.

That seems inline with the study, which was using "high strain exercise activities". Weight lifting usually does not fall into this category.

High strain exercise includes activities that lead to sustained increases in breathing rate, core body temperature, heart rate and mental alertness.

Examples include HIIT workouts (high-intensity interval training), football and rugby games or a long run.

Been there done that. Personally, my cutoff is 4h before bed -- anything later than that and I just won't be able to sleep.

I have a similar problem with eating big meals before bed, it keeps me from sleeping the same way. Only 2h for that one though.

Yeah sorry, there is no other window. I'm a nightowl too, so the early morning is not an option. My sleep is definitely disrupted if I do it 2 hours before bed, but I haven't noticed issues with 4.

My fox said I had to get in better shape or I might get hurt. Started going to Crunch and doing some functional training and heavy lifting but Crunch is about as bad as the gym at my Uni when it comes to college students inhabiting the weight machines for too long. Fox said I didn't need more muscle mass but had to improve functional flexibility and get BMI down (ever see a fat fox?)

So I got a 35 lb kettlebell and a TRX system and do those things as well as VR workouts (some Beat Saber, might get back into Supernatural when I've exhausted the free trials of everyone else) around 8-9pm many nights, I usually got to bed around 10-11pm and sleep well. I think going for a hike is fine even as late as 9pm but I wouldn't want to be doing cardio or HIIT that late. Now that I think about it I oughta add some active isolated stretching with the bands.

What sort of exercise does the fox do?

According to this book foxes are light weight because they jump to capture prey

https://mastodon.social/@UP8/114389122128299887

So far as my fox is concerned [1] I know it puts a lot of stress on my hindquarters (wants to be pronograde?) and to express itself wants to use a range of postures and motion wider than I find comfortable. If I have to explain it to people who might be skeptical I just lie and say I am preparing for character acting in community theater.

[1] https://yokai.com/kitsunetsuki/

> I'm a nightowl too

If you go to bed at 2 am anyway, exercising at 8pm is no problem :)

Unfortunately I have kids school age, so I'm forced to go to bed by 11pm. During spring break it was pretty evident though, if I go to bed at 1 or 2 am and wake up at 11 am, I feel way more rested than if I go to bed at 10:45pm and wake up at 7:45am. Society really doesn't accommodate that

The kids don't like it either :)

I personally noticed that on running. I know #sample=1 but I even used this side effect of exercise to extend a few hours in the weekend nights. On weekdays I am close to the 3-4 hours of distance between exercise and sleep.

I, on the other hand get good sleep if I can do some pushups and sqats and get my body in order after a good early meal. I am otherwise dealing with disrupted sleep. So I would listen to my body.

I often do a spin class on the Peloton to end my day. Around 8pm I'll do a 30-60min ride, then shower, then straight to bed... works well for me.

Depends on what kind of exercise. A few heavy sets of barbell squats or deadlifts will put you out pretty good. Especially the deadlifts.

Is this confounded by pre-workout / caffeine use? I've never had a problem falling asleep after exercise.

Does anybody here use a sleep tracker? I'm curious if your findings are in line with the article.

I am using Garmin Fenix sleep tracking around 7-8 years and checking sleep score everyday. Personally, exercises after 20:00 disrupts my sleep and I sleep later than usual.

Yes, a Garmin. My sleep score and HRV is way off if I run in the evening. It is shocking, actually.

Absolutely. In addition to sleep, any kind of high intensity activity drastically increases what my Garmin calls "stress" for several hours afterwards. This "stress" measurement can also be used as a proxy for sleep quality when asleep.

I find many people in my life seem very precious about their sleep, in a way that I am not.

I also can sometimes endure a day that I detect fatigue in myself. I don't necessarily love it, but I'll note it easy to go to sleep early the second day if I am tired the day before, and if something happens that causes my sleep to feel shorter than i'd like, I don't really worry about it at all.

Same reason I don't really concern myself if I detect notes of hunger in my system. Meh. Sometimes I've fasted a long time, usually I don't fast at all, but I really don't concern myself with "oh my gosh i have not eaten in {recent hours} I am STARVING" energy.

Anyway, I suggest this article to most people I find myself discussing sleep with, and enough people have said it was worth their time to read it, so I continue to share it:

[1] Matthew Walker's "Why We Sleep" Is Riddled with Scientific and Factual Errors

[1] https://guzey.com/books/why-we-sleep/

The animal-ish part of a human existence is always interesting to me. Elsewhere in the comments I've seen sorta uncomfortable references to pressuring someone for sexual intimacy before bedtime based on this paper. Meh. Something that IS really nice before sleep is emotionally connected sexual intimacy, and I hope no one would want emotionally _dis_connected sexual intimacy from/for a partner, and I, personally, would make some big steps back if I thought a partner wanted something like... disattuned sex out of me.

This last paragraph might be best left off the comment, happy if a mod wants to not have it go that way. I do stand by the link to Guzey's "Why we sleep"!

cannot confirm. i have more trouble falling asleep if i didn't exercise at all compared to exercising e.g. 1-2 hours before sleep

the study compares exercise shortly before bed to exercise longly before bed, so I'd say you can't confirm because that's not what you're testing regardless of your results

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