Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
20 Jul

What is the Best Time of Day to Exercise?

Many people, myself included, prefer streamlining fitness to obsessing over its minutiae. Although I’m no fan of their footwear, Nike’s “Just Do It” really does capture my view of what exercise should be. Find what you like doing and what works for you, and simply go do it. But not everyone is that way. Tons of people truly enjoy the nitty gritty details. They like the research, the nutrient timing, the supplementation. They’re the ones discussing the respective differences between sumo deadlifts, regular deadlifts, and Romanian deadlifts. They’re the ones who want to wring out every last drop of performance.

I get that. I used to be like that, too, but now I take more of an academic interest. That’s not to say I don’t pay attention to what I’m doing, because while I like to think I’m just going with the flow and doing what I enjoy, I also like knowing that what I’m doing is effective. Basically, I don’t like wasting time. Plus, many readers fall into the latter category of those who want the details.

Today, I’m going to look at the effect (if there is one) of workout timing. Should you lift in the morning upon waking, or at night? Are the effects of morning exercise different than the effects of afternoon exercise? Does working out right before bed disrupt sleep or improve it? Let’s explore these and other questions as we decide which is the best time of day to work out – if such a thing definitively exists at all.

I’ll go down the line and examine the effect of diurnal variation on various aspects of exercise. Let’s dig in.


If you’re interested in performance, some evidence seems to point toward the afternoon and early evening as the best time to exercise. In one recent study, ten and eleven year old boys performed better in the afternoon than in the morning. Grip strength improved 5.9%, squat jump performance increased 3.5%, the “5 jump” test improved 5%, and performance increased 5.5% (peak) and 6% (mean) during the Wingate test (which measures peak anaerobic output) from morning to afternoon. They also tested the boys in mid afternoon (2:00 PM) and early evening (6:00 PM), but found no difference in performance. This study found a similar result in morning and afternoon PE students using the Wingate test, but the authors suggest that longer warmups during morning sessions could mitigate the performance deficit. So, morning workouts require longer warmups? I can buy that.

Sprinting? Try afternoons for maximal power, but don’t think you’ll have any extra stamina. This study found that maximal power was highest during the first three sprints (of ten total) in the afternoon when compared to morning sprints. Fatiguability was no greater, though.

Another cycling study found that afternoon power output was greater than morning power output in trained cyclists. Fatigue was not affected by time of day, however.

Another study compared the knee extensor strength (via the mighty half squat!) of two groups of trainees. The first group had spent 10 weeks training in the morning, while the second group had spent 10 weeks training in the evening. Both groups improved over baseline, but the evening trainees enjoyed greater strength gains.

I wouldn’t assume that all exercise is better in the afternoon, however. The authors of this study suggest that submaximal exercise – like jogging, walking, hiking, or anything that relies on stamina and little else, really – is not negatively impacted by diurnal variation, which makes sense in light of the previous studies showing that while maximal power decreases in the morning, stamina does not.

Takeaway: Raw power and performance in weight lifting, cycling, and sprinting is highest in the afternoon and evening. Stamina does not increase or decrease, however, and the changes in performance may be mitigated by more extensive warmups. If you’re a high level athlete or really interested in how you perform, afternoons and evenings are best. If you’re just trying to get and/or stay fit, strong, and healthy, morning workouts are just fine.

Hormonal Effects

How does timing change how a workout affects your hormonal profile?

One study found that lifting heavy things in the evening, as opposed to the morning, resulted in a more anabolic (strength and size-building) testosterone/cortisol ratio. Baseline cortisol values were lower in the evening (which is normal) and higher in the morning (also normal; cortisol is necessary for morning wakefulness), which probably explains why evening training worked better. If you’re starting with already elevated cortisol, some intense training is only going to spike it even more. If you’re starting with moderate cortisol, intense training won’t have as negative an effect and your testosterone levels will likely be sufficient to counteract the rising cortisol.

Not all research is so clear-cut, though. In a study on muscular hypertrophy (growth), both morning and afternoon weight-training worked equally well at growing muscles and increasing maximal strength. There was a slight, but statistically insignificant advantage to training at night.

Takeaway: Don’t hop directly under the bar in your pajamas with bleary eyes. Take the time to wake up and relax before working out. That might mean pushing your morning CrossFit class to an afternoon session, or at least a late morning one. We know that cortisol is normally elevated in the mornings, and exercise increases cortisol, so be aware of how the two interact.


How does diurnal variation affect the general health benefits of exercise? Obviously, if you can perform better and reap bigger strength gains in the afternoon, you’ll probably gain more lean mass and lose more fat, but what does the research show?

There are mixed results. Post-menopausal women were split up into two groups in a recent walking study. One would walk in the morning, while the other would walk in the evening. At the end of the study, evening walkers had lower fat mass despite eating larger breakfasts. Both groups improved their aerobic fitness, but the evening walkers did better overall.

Recently, much has been made of the neuroprotective effects of exercise. In other words, the pursuit of brawn appears to lead to brain, too. A recent study found that the neuroprotective effects of aerobic exercise were modulated by its timing. Rats ran for 20 minutes on a rat wheel, either early in the morning or in the afternoon, after which their HAT/HDAC ratios were measured. HAT are histone acetyltransferases, and HDAC are histone deacetylases. The HAT/HDAC ratio indicates how much acetylation is occuring. Higher ratios indicate more histone acetylation and greater neuroprotection, while lower ratios indicate less neuroprotection. So, high is good, low is bad. Both exercise protocols increased the ratio, but the afternoon session increased it more than the early morning session.

But the time of day doesn’t always matter. Check out this study, in which morning and afternoon treadmill sessions were tested for their respective effects on blood fluidity post exercise: blood fluidity improved across the board, regardless of when the exercise was performed. Another study found that resistance training (3 sets of 7 reps at 80% of one rep max) improved platelet function, irrespective of time of day. Morning and afternoon sessions were equally beneficial.

Takeaway: Evening/afternoon sessions seem to be somewhat more protective and beneficial, but morning sessions are also helpful – just less so. And there are other parameters on which diurnal variation has no effect, so it’s not a clear cut answer either way. Let’s put it this way – both are good.


Everyone can agree that exercise in general improves the quality and incidence of sleep. Simply put, if you’re on a regular exercise regimen, you’ll probably sleep better, deeper, and easier. But what about working out right before bed? Will the cortisol spike and keep you awake? Will the increased heart rate keep you from settling down? Let’s find out and look at some studies.

Here’s one that found a 5:00 pm 30-minute session of moderate exercise improved sleep in elderly patients who normally had trouble falling asleep. They fell asleep faster and enjoyed greater satisfaction with the quality of their sleep. Another, using underwater exercise in untrained subjects, found that late afternoon (4:30 pm) exercise had no effect on sleep. Even late night, “vigorous exercise” may not negatively impact your sleep, as a study in trained cyclists showed. The subjects were able to get to sleep 30 minutes after three hours of cycling at 65-75% of their max heart rate without issue.

Takeaway: Unless you personally find that late night exercise negatively impacts your sleep, don’t worry about exercising at night.


We’re all individuals here, but there may be patterns of workout consistency that correlate with the timing of workouts. Do morning exercisers work out more consistently than afternoon or evening exercisers?

One study found that people who exercised in the mornings were more likely to exercise in general, while people who said they exercised at night or in the afternoon were less active overall. I wouldn’t read too much into this, and I think a likely explanation is that people who are willing to wake up early to work out are more likely to stick with something – like a workout regimen. Early risers are generally more consistent, I think most people would agree, and this research bears that out.

Takeaway: Epidemiology is nothing to hang your hat on. Correlations may indicate something about populations, but if you, yourself, find you exercise better at a particular time of day, they are almost useless.

As for me, I like late morning workouts, but that’s just because late morning works best for me and my schedule. I’m not trying to optimize my hormonal responses, boost my metabolism, or maximize my workout grip strength. I’m just working regular exercise into my daily routine, when and where it fits.

You can read the research and follow the links, but ultimately, the best time of day to exercise is the time of day that works for you. If you’re dead tired after work, perhaps a morning session is the answer. If late night workouts keep you buzzed and awake, move them back an hour and go from there. Also, as the context of your life changes, you’ll have to mix up your workout schedule on the fly. Get a bad night’s sleep? Your cortisol is raging, and a late afternoon workout is probably better than an early morning one.

When do you workout? Does it work for you? Thanks for reading, and be sure to let us all know about your workout schedule!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I think it’s great that all the detail and links are here for those who need them – it’s great info, all very well researched.

    For me, I’m happy to be at about the same place as Mark: “I’m not trying to optimize my hormonal responses, boost my metabolism, or maximize my workout grip strength. I’m just working regular exercise into my daily routine, when and where it fits.”

    Fairly recently, I changed by sacred, much-loved early morning bike ride to much later in the day – for 2 reasons: 1) I found (by experimenting) that early morning is the time I get my best writing done; 2) After I’ve been writing for a few hours, the best way to recharge is with a bike ride.

    So I resequenced, and things work better because of it. But I happen to like early morning rides better. So I treat myself to early morning rides on weekends.

    Great post!

    Susan Alexander wrote on July 20th, 2011
  2. I definately find that as I get older(58) and workout in the mornings…I need a good warmup, if I am going to ramp up and do some hard work. Doesn’t matter if it’s hot or cold outside…I still need the warmup…I didn’t used
    to feel it was that important…but now I do…

    Gman wrote on July 20th, 2011
  3. Being a fitness expert I’ve pretty much heard it all when it comes to exercise timing for weight loss, performance, etc. In the end, I think the best thing you can do is figure it out for yourself – we’re all different. For example, I do really well mentally in the morning. I can be more productive between 6-7am then I can all evening. But forget about working out in the morning, I hate it, I can’t do it. I give my best effort, and therefore get the best results, when I workout in the evenings.

    I think that’s the key right there – workout when you feel you give your best effort, because it is only then that you will achieve the greatest results.

    Primal Recipe wrote on July 20th, 2011
  4. Crack of dawn or nothing: I was out the door at 4:30 or 4:45am all freezing winter(but now that I’m jobless, it’s more like 5 or 6 am). Anyway, I can’t even conceive of running any other time (5 kids, crazy schedule) but in college I would often run at midnight. Three cheers for reflective vests :)
    A time and a season for all.

    Milemom wrote on July 20th, 2011
  5. Great article. I generally workout late afternoon. I can’t wait to get home from work and hit my gym. On the other hand, in the am I’m a slug. I get told all the time that one must workout in the mornings or there is not much benefit (not that I listen to them).

    Except for hiking, I like pm workouts.

    CathyN wrote on July 20th, 2011
  6. I like to workout at noon or early afternoon. If I workout to early I feel like my strength is compromised. If I workout to late then it messes up my sleep.

    Gary Deagle wrote on July 20th, 2011
  7. According to the spinal biomechanics expert, Dr.Stuart McGill, in his book “Ultimate Back Fitness and Performance” he states that you should avoid doing anything that involves bending and twisting in the first hour after waking up because spinal discs fill with fluid overnight the extra fluid magnifies whatever stresses put on the discs.

    Marc wrote on July 20th, 2011
  8. I crossfit at 6:30 every morning. When I go to an evening class due to a morning conflict such as a doctor’s appointment, I find that I do not perform as well. I think it depends on what your body is used to. If you have a sleep schedule and are used to waking up to work out, and not used to working out in the afternoon evening, I think you will find performance better in the morning. It is all in what you have trained your body to do.
    I have also found that I am weighed down by food and overly tired after a long day at work. I like my morning banana and a few nuts before Crossfit so I do not have too much in my stomach.

    Tori wrote on July 20th, 2011
  9. I found doing my CrossFit WOD in the morning (i’m talking the 6am class) tends to give me a ton of energy throughout the day, even though it hurts like hell getting out of bed that early.

    WhatAboutJason wrote on July 20th, 2011
  10. I like to workout right in the middle of the afternoon! It kind of splits my day up and I always have the most energy for my workouts around this time as well :)

    Mark wrote on July 20th, 2011
  11. I prefer working out earlier in the day just because your more likely to get a good workout in and not skip it instead.

    The longer the day goes for most people the more tired they get and then come the excuses.

    Fitness Guy wrote on July 20th, 2011
  12. I workout in the late afternoon but would prefer late morning if I had my druthers. It makes it easier to work out in a fasted state and then it is over with and won’t potentially limit anything else I want to do that day, as opposed to feeling like, “If I do this or that, it will ruin my workout later.”

    Masterlock wrote on July 20th, 2011
  13. I love an early morning workout, but I stay too busy to get up that early in the morning, so now I am a late afternoon workout person. I love the gym, it hot in there like it would be outside. On Saturday mornings, I love to get up and walk. I agree with Mark, just do it…that counts for more than anything!

    Jenn wrote on July 20th, 2011
  14. Just my quick n = 1 experience. I’d exercised for many years (about 15 years at the time) almost exclusively in the late afternoon or early evening. Because of job requirements, I switched to early morning (between 6 a.m. and 7 a.m.). The first few months are a foggy blur as I was much weaker and slower—-physically and cognitively! After a few months, however, my body apparently adapted (big shock) and I was back to normal. When I had an occasional evening session, I was not as strong as I was in the morning. After about two years I switched jobs and my exercise went back to afternoons (usually during a late lunch break around 2:00); I went through the same adaptation experience.

    So my guess is that your body will adapt to whatever you throw at it. Otherwise, we could just keep doing the same thing over and over and we would improve; and anyone that exercises can tell you that doesn’t generally happen. My own experience is that, for me, if I stick to a consistent time, I make better improvements. Maybe because of a stabilized cycle for hormones changes, maybe diet, or maybe something in my head, who knows for sure? I think the consensus here is to keep on Just Do(ing) It!

    Patrick wrote on July 20th, 2011
  15. Jack Lalane. 4:30 am to 6:30 am. 7 days a week, from age 15 to 96. (I guess he did lighten up and started at 6:30 in his late 80’s).

    dave wrote on July 20th, 2011
  16. i work out before most people even think of waking up. it’s simply because that’s the only time i have. in the rare case that i get to workout later, i’ll tell you i am AMAZED at how much MORE strength, power, flexibility and speed i have. i’m like a different person.

    tracy wrote on July 20th, 2011
  17. Jack Lalane. 4:30 every morning. Done.

    dave wrote on July 20th, 2011
  18. I do much better with an afternoon work out. I find that a 3pm work out gives me a boost into the evening activities of preparing dinner/helping with homework/etc. and with a much better state of mind ( if I had a bad day at work, I can kick box it away) and centers me.
    I tried the morning work outs and would find myself dragging in the late afternoon/evenings and then ended up having trouble sleeping.

    Claire wrote on July 20th, 2011
  19. I was an aerobics and gym instructor for many years I took morning and evening classes, jogged for an hour most days and weight trained and never had any trouble sleeping. I gave that up 11 years ago to become a lab analyst, I still workout, intervals, sand bag etc but have a lot of trouble getting enough sleep. I’ve tried training in the evenings and morning. I’m very resistant to taking drugs but when desperate I will. I’m leaner now than ever just need to get enough sleep.

    jayde102 wrote on July 20th, 2011
  20. i always do my workouts in the morning because it gives me agood drive for the day and about the meal issue, i had better have agood carb diet after my workouts giving my body what it needs to feel energised and ready to go!

    david wrote on July 20th, 2011
  21. I never work out in the morning…hiking,golf,Mtn Biking maybe, but for the most part morning = waking up, reading,writing & doing paperwork…I row at noon break & ride (usually stationary) between 4 & 6. This works best for me!

    Gavin Blair wrote on July 20th, 2011
  22. More moms with kids could get to the gym if they realized that they could work out at 5:00 a.m. and be back home by the time the kids woke up.

    That’s how I figured out a time of day just for me to get in really good shape in 2007. I’m still going strong ever since!

    :-) Marion

    Marion@affectionforfitness wrote on July 20th, 2011
  23. Since I work in a management position, which is largely administrative, I do Crossfit at 1130 religiously everyday. Then in the evenings for mobility sake, because of the sitting, I enjoy a brief three or four mile run to get the blood flowing again. Plus it is relaxing. Try as I might, I have never been the type to workout in the mornings.

    Dain wrote on July 20th, 2011
  24. I workout at night. I’m not much of a morning person and every time I do attempt a morning workout, I never have the energy I need. I’m always entirely too lethargic, then I find the workout just makes me more tired and delays my waking up and being productive on other things throughout the day. Working out at night seems to help me sleep better and I have a lot more energy to put effort into my workout.

    Ashley wrote on July 20th, 2011
  25. I love working out in the mornings! I am straight out the door for a few miles of off-road running. Not only the fitness but being out in the country helps to ground me before a hard days work. It gives me the kick start to my day. i notice that if I work out later I perform better. But like you mention in your write up, I too exercise for pleasure and not just for fitness. Interesting post and thank you!

    Sassie :)

    Sassie wrote on July 20th, 2011
  26. I’m a mid morning worker-outer as well. Ever since eating more primally, I can postpone breakfast no problem and work out on an empty stomach. I remember the days I HAD to eat before working out or I would fatigue so quickly but it’s the opposite now. If I eat first (carbs) my blood sugar drops quickly. I think the key is finding a time you will stick with and getting in a routine.

    katie wrote on July 20th, 2011
  27. Mid morning, around 8 or 9 after a couple cups of strong joe. Drink lots of lime squeezed water during and after. Then after protein and more protein. Works great.

    Lee wrote on July 20th, 2011
  28. Morning sucks. In fact, anything before 10:00 AM sucks. If forced to get up early – especially before the sun is up – I spend the first 15 minutes sitting on the pot trying to figure out who the heck I am, and spend the rest of the day sick to my stomach. I repeat: morning sucks. There’s no worse sight than the sun rising – new day ahead notwithstanding—

    I’ve never been a morning person for anything, and after almost 67 years, nothing seems to have changed. I still working out in the early afternoon, enjoy hiking or just walking my daily walk during the mid-afternoon and do my best work physically and mentally in the early evening. I “wake up” as the sun goes down.

    When in college, I did my best studying at night until about 3:00 or 4:00 AM. I guess I’m half-assed backwards.

    Anyway, now, I work out and walk/hike during the mid-afternoon/early evening. Since it’s just me and DH I (read: “retired”) I can afford the luxury of not having to worry about kids/job and can afford to do what I want to do when I feel like doing it. Somehow there’s no better feeling than that, IMHO. I put in my time and don’t need to even think about going back there again.

    PrimalGrandma wrote on July 20th, 2011
  29. I actually LIKE my Nike Free’s. They protect my feet enough to run the trails in the CO Rockies (where I live), but they are light, breathable and let my foot feel the earth. (This is in response to Mark not liking Nike’s–a little off topic, I know.)

    I favor morning workouts because:
    1) fits my schedule
    2) I’m consistent with it
    3) great way to start the day
    4) no sunburn!

    Ruth wrote on July 20th, 2011
  30. Seems pretty logical to me that the evolutionary expression of our genes with respect to exercise, would be for it to be somewhat variable throughout the day as well as from day to day.

    Our paelolithic ancestors were likely physically active at various times of the day depending on the state of their environment (weather, hunting, gathering, playing, surviving, etc.).

    I think we should exercise whenever we have an opportunity to do so. So although most of us are tied to a structured schedule within our modern neolithic lifestyle, we should strive for irregularity and randomness when it comes to our exercise goals.

    Asturian wrote on July 20th, 2011
  31. Out of topics?…

    Al wrote on July 20th, 2011
  32. I am a trainer myself and I have the convenience of traiing morning, afternoon, or evening. Personally I prefer late mornning mid-afternoon. Everyone is different relative to their ideal time of day to train.
    By the way, I enjoy training in the heat and elements. That is part of being primal!

    roberto wrote on July 20th, 2011
  33. For me, I never worked out when I tried to do it in the evening. Too many other things vying for my attention. What works for helping me be consistent with my workouts is to make it part of my regular morning schedule. Most of the year, that means dropping the kids at school and heading to the gym. During the summer, it means the kids get me up and we all head to the gym together. I do what works for me, but if something else works for someone else, good on them. Why split hairs over something personal like that?

    Sanctus Real wrote on July 20th, 2011
  34. I definitely prefer morning workouts. It’s such a positive way to start my day. Unfortunately, my schedule doesn’t always allow me the option, so I’ll take whatever time I get.

    Tree wrote on July 20th, 2011
  35. With 3 kids under 4, the mid-morning gym-session works best for as that’s when the gym-creche is open. I’m thinking anytime between 9-11 am. But I do my walking at 7 pm daily. It still my busy mind and make me sleep better once I go to bed at 10 pm.

    Ivy wrote on July 20th, 2011
  36. I’m a morning girl. I cannot start my day until it’s done! :) It’s a cup of coffee… ha, without the cup and the coffee!

    GiGi wrote on July 20th, 2011
  37. I do both

    usually 3 or 4 evenings in the week (about 5pm) and then saturday or sunday morning (around 9am – although I’ll be awake from 6.45am)

    I dont really notice a great difference, I think alot of it can come down to mental attitude. If you think you cant train at a particular time you wont be able to.

    Daniel wrote on July 21st, 2011
  38. Great Article….and my take-away- CONSISTENCY IS THE KEY…. from my own body I realized that whenever I worked out in the evenings, I could almost always lift more. However, I have also found that I become much more erratic and irregular when I go in the evenings. Basically, Life/Demands made by others/Work related crises tend to come in the way at least a few times per week whereas whenever I go in the mornings…I stick to it like clockwork, So morning it is for me as it never gets edged out due to other priorities…

    Plus, sometimes I am so buzzed after the gym, breakfast and a shower in the mornings that I literally breeze into office singing Bollywood songs…..The good Vibe usually stays till lunch :-)

    Rahul wrote on July 21st, 2011
  39. Wow! I always thought I was strange because u feel best working out in the afternoon, but everyone I know prefers the morning. In just too stiff and groggy! I actually started the whole thing, running at midnight to relieve new mom stress.

    Unshod Sarah wrote on July 21st, 2011

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