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Who Wins in Fitness: Early Birds or Night Owls?


By Rachel Welch


Whether you’re an early bird morning person, a night owl, or a permanently exhausted pigeon, you have probably heard the rumor that to be successful, you must wake up at five or six in the morning to exercise. There have been numerous articles on this alleged early bird benefit, which has further inspired the natural morning lovers, and added extra pressure to those who just can’t function before 10:00 a.m. Some surprising research came out recently that presented a contrasting opinion and suggests that it may be more beneficial to exercise in the afternoon than in the morning. It’s safe to say that the world’s night owls are rejoicing over their newfound validation. But, what are the benefits, and what does the research tell us? Let’s dive into what we know about morning versus afternoon and evening workouts, and help you decide how best to plan your day.


Why Bother?


Exercise is undoubtedly an excellent addition to your day, whether in the morning, noon, or night. It stands to reason that people who exercise would want to know how to reap the maximum benefit from their workout and energy expenditure. In case you need a refresher on why exercise is so amazing, here are just a few benefits that come from regular movement.


Benefits of Moving Your Body


Exercise not only helps the body, but also the brain. Some of the biggest boosts to brain health come right after a burst of physical activity and vary with age. For children, exercise can lead to better mental performance and memory. For adults under 50, it can lead to improved mental health, reduced anxiety, and better sleep. For adults 50 and up, it can improve quality of life, reduce the risk of dementia, and reduce the need for sleep aids and medication (1).


Physical movement also has multiple benefits for the body, including weight management, weight loss, and a reduction of associated health risks. With regular exercise and consistent movement, you can feel accomplished in multiple ways, and know that you’re reducing your risk of:


  • Cardiovascular disease: Research shows that around 20-minutes of exercise per day can reduce your risk of heart disease and stroke. Specifically, 150 minutes a week has been proven to provide this benefit, and you can increase the benefit by working in even more exercise.
  • Type 2 diabetes: Aiming for the same 20-ish minutes a day will also boost your body’s protection against type 2 diabetes. This is partly due to exercise’s benefit to overall cholesterol and blood sugar. Even with slightly less than 150 minutes a week, you can still gain benefit and defense against this and other ailments.
  • Certain cancers: The risk of certain cancers has also been proven to decrease when people are consistently active. Some of the cancers that the CDC references include breast, colon, kidney, lung, and stomach. All of these are shown to be less common among people who exercise regularly (2).


If those meaningful health benefits aren’t enough to motivate a new exercise regimen, then also take into consideration that movement benefits your muscles and bones plus helps to keep you fit and strong even as you age. With the combined perks of healthier mental health, physical health, and longevity, what’s not to love?


Surprising Science


Now, onto the recent study that threw into question the benefits of rising before dawn. A team of scientists conducted a randomized, controlled trial with 11 men, all of whom were diagnosed with Type 2 diabetes at the time of the study. The participants ranged between ages of 45-68 years, and participated in a two-week long trial, in which they consistently exercised in either the morning or the afternoon, and every participant completed the same high intensity interval training exercise at either their morning or afternoon time slot.


The researchers tested the men’s blood glucose levels before and after each phase of exercise, in the hopes of discerning a difference between morning and afternoon results. They found that the afternoon workouts yielded a more meaningful improvement in the blood glucose levels than the morning workouts. They also found that the morning workouts actually led to an increase in participant blood glucose (3). This study launched a flurry of excitement and buzz, which was reported on by the New York Times, Forbes, and other notable publications.


Some of the experts that they consulted made connections between the timing of meals and exercise. A professor at Maastricht University theorized that exercise later in the day may help with the body’s ability to break down subsequent meals like dinner, and help the body enter into a fasting state while asleep, which could help with balancing blood sugar and weight loss. The conclusion that the professor came to is that exercise at any time of day is better than none, but that afternoon exercise does seem to be more beneficial than morning exercise (4).



The groundbreaking afternoon exercise study, while interesting, comes with some limitations. For one, they only tested men with Type 2 diabetes and did not observe the effects on men without Type 2 diabetes, or any women. So, while the results for men with diabetes are meaningful, it is unclear if the same results would be applicable to other groups of people with different health situations.


Mini Mouse Treadmills


There is still a substantial amount of research surrounding the benefits of morning exercise that shouldn’t be disregarded. Some studies even distinguished between morning and evening exercise, such as a rodent-based study that was completed in 2021. The researchers focused on a group of lab mice, with an aim to find out what time of day was best for the mouse to exercise, through comparing metabolic responses. They took into consideration the natural circadian rhythms of the mice, as well. How does one test a mouse-focused exercise routine you may ask? Why, with a tiny laboratory-based mouse gym, of course.


The mice were prompted to run on itty-bitty treadmills, while the researchers studied their genes, molecules, and metabolisms. They found that the timing of exercise changed the impact on tissue, liver, heart, and brain performance, with specific differences in fat burning versus blood sugar. They found that mice who exercised (on their custom-made mouse treadmills) in the morning burned more fat, while the mice who exercised in the evening gained better balance in their blood sugar (5). If these results are truly comparable to human metabolism and blood sugar, then it would suggest that morning exercise is better for fat burning, while evening exercise may bring more improvements to blood sugar maintenance.


Another study focused on non-mouse athletes and found that cortisol may play an important role. They argue that because cortisol is higher upon waking in the morning, that morning athletes may be more inclined to develop an exercise habit (6).


Morning Exercise Pros and Cons


A common argument in favor of the early workout time relates to the quiet, uninterrupted time that you can obtain in the wee hours of the morning. Many successful early risers claim that the hours before their kids wake up, or before their colleagues start calling, is the most productive time for them. Other morning people suggest that their morning exercise gives them a boost of energy which carries them throughout the day, and that morning exercise helps encourage them to make healthier food choices as well. However, there are downsides to morning exercise that many of the early bird advocates may not cover.


In the morning, the body is not warmed up yet. If anything, it is stiff from lying still all night, and cooler due to the body’s core body temp lowering during sleep. This can mean that your morning workout requires more warmup time than say, an afternoon or evening workout. Additionally, there is the risk of losing valuable sleep by setting an early alarm. Very few people receive the proper quality or quantity of sleep due to various factors, and usually can’t afford to lose any more. This is important to keep in mind if for instance, you are kept up later than normal due to unusual circumstances. Would it be worth it to lose sleep in favor of a morning workout?


Afternoon/Evening Exercise Pros and Cons


On the flip side, there are benefits to an afternoon or evening workout. Later in the day, it is likely that your body will already be warmed-up from accomplishing morning chores and rushing to the office. This means you may not need as much of a warmup routine as you might in the morning. Also, hormone levels like testosterone increase later in the day, meaning a later workout may help you gain muscle faster. Finally, a later-day workout can be an excellent way to burn off the stress of the day, and the related endorphins can help you sleep better.


The down side to exercise later in the day is that it can interfere with your sleep quality if it’s timed too close to bedtime. For some people (not all), late night exercise can make them jittery, which makes it harder to relax and wind down. Evening exercise also can come with issues of consistency, as evening plans and social events usually come up in the evenings versus in the mornings (7).


Exercise Every Day


Perhaps you’re reading this and feeling that while informative, you need to rewind a smidge, because you can’t bring yourself to exercise every day. If that’s you, you are absolutely not alone. There is a reason that almost every new year brings fitness-based resolutions for most of us. Exercise, while massively beneficial, can be difficult to integrate into everyday life.


It’s important to add gradual change that can be maintained and prove sustainable for years to come. This is true for change related to new habits of all kinds, including diet and exercise. This ideally would center around exercise that you actually enjoy, that's semi-convenient, and that doesn’t break the bank. We’ve all been tempted at one point or another to buy into a fabulous new gym, new private training session, or glamorous studio, but often those changes are short-lived. When deciding how to build exercise into your everyday life, consider what is most convenient, attainable, affordable, and fun. You can do this by incorporating workouts into your own space, in a local gym that’s on the way to work, or even a peaceful park that you pass on the way home.


Timing Isn’t Everything


Is it better to exercise in the morning, or later in the day like in the afternoon or evening? The research has spoken and leaves us with a somewhat unclear answer. It seems that there are benefits to both. Morning exercise may allow for increased fat-burning, while afternoon and evening workouts may allow for balancing blood sugar and more powerful performance. Ultimately, it seems that the best time to exercise is at the time that works for you. If you’re a morning person, go forth and get that early-morning worm! If you’re a night owl, thankfully you can gain some benefits from your preferred workout time as well. Ultimately, exercise at any time is fantastic, and timing isn’t everything.


  1. 1. Physical Activity Guidelines for Americans 2 nd edition. (n.d.). https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf#page=39
  2. 2. Centers for Disease Control and Prevention. (2021, November 1). Benefits of physical activity. CDC.gov; CDC. https://www.cdc.gov/physicalactivity/basics/pa-health/index.htm
  3. 3. Savikj, M., Gabriel, B. M., Alm, P. S., Smith, J., Caidahl, K., Björnholm, M., Fritz, T., Krook, A., Zierath, J. R., & Wallberg-Henriksson, H. (2018). Afternoon exercise is more efficacious than morning exercise at improving blood glucose levels in individuals with type 2 diabetes: a randomised crossover trial. Diabetologia, 62(2), 233–237. https://doi.org/10.1007/s00125-018-4767-z
  4. 4. Reynolds, G. (2021, January 27). The Best Time of Day to Exercise. The New York Times. https://www.nytimes.com/2021/01/27/well/move/the-best-time-of-day-to-exercise.html
  5. 5. Sato, S., Dyar, K. A., Treebak, J. T., Jepsen, S. L., Ehrlich, A. M., Ashcroft, S. P., Trost, K., Kunzke, T., Prade, V. M., Small, L., Basse, A. L., Schönke, M., Chen, S., Samad, M., Baldi, P., Barrès, R., Walch, A., Moritz, T., Holst, J. J., & Lutter, D. (2022). Atlas of exercise metabolism reveals time-dependent signatures of metabolic homeostasis. Cell Metabolism, 34(2), 329-345.e8. https://doi.org/10.1016/j.cmet.2021.12.016
  6. 6. Jo, PhD, S. (2021, July 28). When Is The Best Time To Exercise? Forbes Health. https://www.forbes.com/health/body/when-is-the-best-time-to-exercise/






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