Best Time to Exercise: Benefits of Morning Vs. Nighttime Workouts

Everyone wants to get in good shape. Whether for v-cut abs, a healthy heart, or peace of mind, exercise is the avenue to achieve many goals. The biggest challenge -- besides the workout itself -- is carving out enough time for that run, or an hour-long hot yoga class. 

Having a full-time job means most people can’t lift weights or hit the gym in the middle of the day.  Still, those dedicated few, work hard to finagle an hour or two for a stress-burning workout.

Most people find time to exercise at the beginning or end of the day. Some athletes swear by a swift jog, as the sun rises. By getting exercise out of the way, they can enjoy the rest of their day refreshed and productive.

 Others prefer to work out as a way of closing out their evening.  Sometimes lifting weights or doing pilates after a long day of work can be a convenient way to relieve some stress. 

Practical and personal reasons aside, is there a best time to get your fit on?  Well, the science suggests that there may be certain advantages and disadvantages to working out in both the morning and evening.⁽¹⁾

Benefits of Morning Workouts

The alarm clock buzzes. Time to wrangle your sneakers and head out the door for your early morning workout.  But besides the feeling of absolute human superiority, what are the true benefits of working out early in the A.M.? 

Well, according to several studies, early risers can enjoy improved sleep, better oxygen flow, and stronger muscles.⁽²⁾⁽³⁾ In other words, you may potentially sleep better, enjoy better workouts, and help support your body’s natural rhythms. And of course, the glorious feeling of feeling accomplished -- well before you’ve even had your cereal. 

Morning Workout May Lead to Better Sleep Quality

A study by Sleep Medicine found that people that worked out in the morning actually fell asleep easier and longer than people who had worked out in the evening.⁽⁴⁾ Findings suggest that working out in the morning helps even out your blood pressure by bedtime. 

During the night, a sleeper’s blood pressure lessens by 15 percent, benefitting the heart and helping the body rejuvenate. Exercising in the morning helps the body prepare for this dip in blood pressure, as opposed to working later in the day. 

Essentially, by pushing your body earlier in the morning, you are getting it in the right cycle to catch some deep sleep cycles in the night. And as we all know, the better rested you are, the easier it will be to wake up -- and jump back into the early bird workout routine! 

Working Out in the Morning May be Better for Your Oxygen Uptake

Another way working out earlier helps your body regulate itself is through VO2 kinetics, which refers to the rate at which oxygen is delivered throughout your body during a period of exercise. 

Research published in Chronobiology International showed that oxygen flows more efficiently in a person working out in the morning instead of the evening.⁽⁵⁾  In the study, fourteen male cyclists worked out in both the evening and the morning with a one-day buffer in between training sessions.

It was found that their breathes contained far more oxygen after cycling in the morning compared to the evening. Oxygen is an essential component to any workout but it’s especially important when it comes to aerobic workouts.  The oxygen that flows through your veins is used to create fuel for your muscles -- the more fuel in your system, the better your performance. 

Morning Workouts May be Better for Muscle Contractions and Fatigue

Those who hit the gym before the sun rises may also experience better muscle contractions, as well as, less muscle fatigue during their workout.  

In the same 2007 study published in Chronobiology International, participants did repetitive knee pulls some in the evening and some, of course, in the morning.⁽⁶⁾ At the conclusion of the study, it was found that participants’ muscles were significantly less fatigued when they worked out in the morning, compared to the evening. Additionally, their contractile capacity went up -- contractile capacity measures the amount of force a muscle is able to produce. 

So better sleep, better oxygen flow, and stronger muscles -- the benefits of working out in the morning seem endless! And of course, there are the practical benefits as well. Exercising in the morning means you’re not dreading that SoulCycle class at 8 PM after work.

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Benefits of Nighttime Workouts

By now you might be thinking the only time to work out is in the morning. However, that’s not necessarily the case. In fact, evening exercise can be just as rewarding as morning workouts. 

For many people, sometimes it’s just not possible to hit the gym at the crack of dawn. Additionally, some people simply prefer evening workouts -- be it for social purposes or for the cooler evening air if you’re a runner. 

Preferences aside, research shows that there may actually be several benefits to a post-5PM workout regime. Several trials have demonstrated that you may get tired during your workout less quickly in the evening.  On top of that, you may also have a faster aerobic system and lower cortisol response as well. 

You May Be Able to Workout Longer at Night

If you hit the gym after work, you might find that you are able to work out for longer. In a study published in The Journal of Sports Medicine and Physical Fitness, it was found that men and women had a greater time to exhaustion when completing high-intensity exercises in the evening, compared to the morning -- people lasted 9% longer, on average, when they worked out later in the day.⁽⁷⁾

In another study, competitive cyclists tested their endurance at different times in the day.⁽⁸⁾ The cyclists’ peak power was measured, and these peak times lasted far longer at 6 PM compare to 6:00 AM.  Why? Researchers hypothesize that our bodies may be more efficient at conserving oxygen later in the day.

You Might Be Stronger in an Evening Workout

So you might be able to work out for a little longer in the night time compared to in the morning, but did you know that you may be a little stronger in the evening as well? 

One study published in Isokinetics and Exercise Science measured participants’ grip strength (amongst other factors) at three different times --  9 AM, 1 PM, and 5 PM.⁽⁹⁾ The researchers ultimately found that participants’ muscle force was significantly greater in the twilight hours compared to the dawn. 

You May Have a Lower Cortisol Response at Night

Another potential benefit to working out at night has to do with your body’s hormonal response to exercise-induced stress.  An intense bout of exercise can increase your body’s production of the stress hormone cortisol. High levels of cortisol can impinge on the ability of your muscles to respond and react to an intense bout of exercise, hindering your progress and recovery.    

however, some research shows that your body’s cortisol response to exercise may be less severe at night time.  For example, a 2001 study published in The Journal of Clinical Endocrinology & Metabolism, ultimately found that, on average, participants saw a significantly lower cortisol response at  7 PM compared to 7 AM. ⁽¹⁰⁾

So When Is the Best Time to Exercise?

To sum up, there may be certain pros and cons to working out both in the morning and at night. Forcing yourself to wake up at the crack of dawn, throw on your running sneakers, and hit the pavement, helps to prime your body for better sleep. There are also more anaerobic (short-term) oxygen benefits, and you’ll gain strength quicker as well. 

If you’re not a morning person, there are still plenty of benefits to working out in the evening. Your body may be able to produce more oxygen during an evening workout, ultimately allowing for more endurance.  On top of that, you may also have more available strength when you workout at night. And of course, a good workout at the end of the day is always something to look forward to. 

Since there are potential pros and cons to working out both in the morning and at night, figuring out what time is best for you ultimately depends on your training goals and personal preferences. 

• References
  1. “Morning and evening exercise”Seo, D.Y., Lee, S.R., Kim, N., Ko, K.S., Rhee, B.Y., Park, B.J., Han, J. Integrative Medicine Research. Dec. 2013.
  2. “Effects of acute morning and evening exercise on subjective and objective sleep quality in older individuals with insomnia”Morita, Y., Sasai-Sakuma, T., Inoue, Y. Sleep Medicine. Jun. 2017.
  3. “Morning-to-evening differences in oxygen uptake kinetics in short-duration cycling exercise.”Brisswalter, J., Bieuzen, F., Giacomoni, M., Tricot, V., Falgairette, G. Chronobiology International. 2007.
  4. “Effects of acute morning and evening exercise on subjective and objective sleep quality in older individuals with insomnia.”Morita, Y., Sasai-Sakuma. T., Inoue, Y. Sleep Medicine. 2017.
  5. “Morning-to-evening differences in oxygen uptake kinetics in short-duration cycling exercise.”Brisswalter, J., Bieuzen, F., Giacomoni, M., Tricot, V., Falgairette, G. Chronobiology International. 2007.
  6. “Morning-to-evening differences in oxygen uptake kinetics in short-duration cycling exercise.”Brisswalter, J., Bieuzen, F., Giacomoni, M., Tricot, V., Falgairette, G. Chronobiology International. 2007.
  7. “Effect of time of day on aerobic power in exhaustive high-intensity exercise.”Hill, D.W. The Journal of Sports Medicine and Physical Fitness. Aug. 1996.
  8. “Time-of-day effects in maximal anaerobic performance and blood lactate concentration during and after a supramaximal exercise”Isler, A.K. Isokinetics and Exercise Science. Nov. 2006.
  9. “Time-of-day effects in maximal anaerobic performance and blood lactate concentration during and after a supramaximal exercise”Isler, A.K. Isokinetics and Exercise Science. Nov. 2006.
  10. “Cortisol and Growth Hormone Responses to Exercise at Different Times of Day”Kanaley, J.A., Weltman, J.Y., Pieper, K.S., Weltman, A., Hartman, M.L. The Journal of Clinical Endocrinology & Metabolism. Jun. 2001.