What Science Says About the Best Time to Exercise: A Research-Based Guide

 By Eisa Khan | April 13, 2026

Reading time: 7 minutes

Disclaimer: I am not a doctor or exercise scientist. This paper is an overview of peer-reviewed articles and professional advice. It is important to never undertake a new exercise routine without consulting a physician.

Why I wrote this Guide:

I am not a personal trainer, I am a researcher and an enthusiast about fitness. I have not acquired an exercise science degree. However I have read more than 100 hours of studies, expert podcasts, and analyzed data, on the timing of exercise.

Why? Because I was interested in knowing: Does it really matter when you exercise?

The answer to this is yes. But not because most people think so.

What I have learned is summarized in this guide based on 15 or more scientific studies and two certified trainers interviewed. I have also tried some of this on myself. Where it is personal experience with me, I will inform you. Where I am recapping research, I will inform you of that too.

What the Research Says: Morning Exercise

The Benefits

Several studies have demonstrated that there are special benefits to morning exercise:

Consistency: In a 2017 article published in the journal Medicine and Science in Sports and Exercise, researchers discovered that individuals who exercise in the morning tend to adhere to their exercise routine over time. Participants who exercised in the morning mentioned less schedule conflict and decision fatigue.

Fat burning: A study in the Journal of Physiology (2019) has concluded that pre-meal exercise more effectively burns fat (fat burning) than does post-meal exercise. The cause: in the morning, your insulin level is lower, and thus your body burns more fats.

Blood pressure: A 2018 study in Hypertension discovered that morning exercise reduced blood pressure better than evening exercise in participants with high blood pressure.

The Drawbacks

In the morning the body temperature is lower and this means that your muscles are stiff. You should have a longer warming up.

• The early morning (peak lung function is around 4pm) is when lung function is worse.
• The strength of the morning is approximately 5-10 less than afternoon strength.

Personal Experiences:

I experimented with morning exercise in 30 days. 

Walking: I took 30 minutes of walking right after waking up and then I took a breakfast.

My score: I was also more consistent (I missed 2 days compared to my average of 8-10 missed days). I did not observe that there was a drastic effect on the weight loss, but I felt more active throughout the day.

My battle: The initial 10 minutes were difficult. My legs felt heavy. In 10 minutes I was warmed up and felt okay.

What the researchers say: Afternoon Exercise.

The Benefits

Afternoon workout (between 1pm and 4pm) is in line with the rhythms of your body:

The highest body temperature is during the late afternoon. Your muscles are more relaxed, warmer, and generate more force. A 2019 meta-analysis in Frontiers in Physiology discovered that afternoon strength and power output are 5-10% greater than morning strength and power output.

Hormones: Cortisol (stress hormone, which is capable of breaking down muscle) is less in the afternoon. Testosterone (important for muscle growth) is at a moderate level.

The afternoon is the best time to have the reaction time and coordination. This is important in exercises such as weight lifting, tennis or martial arts.

The Drawbacks

Scheduling is harder. There is always the interference of work, family and other commitments.

The late afternoon and early evening is when the gyms will be more packed.

Sleep disturbance: According to some studies, sleep is disturbed in some individuals when they engage in vigorous exercise late in the day (after 8pm).

I interviewed a certified strength coach (who asked to remain anonymous). He said:

"If you want to lift heavy or set a personal record, do it between 2pm and 5pm. I have seen it with hundreds of clients. They are simply stronger in the afternoon."

What the Research Says: Evening Exercise.

The Benefits

Exercise in the evening (around 5pm to 8pm) also has its benefits:

• Stress release: exercise will help release cortisol and clear your mind after a hard day of work.
• Social opportunities: It is more likely to attend a group class, team sports, and gym sessions with friends in the evening.
• The time of peak lung performance occurs in the late afternoon and early evening. Your oxygen efficiency is approximately 5 per cent more than in the morning.

The Cons (And How to Remedy Them).

Sleep disruption is the greatest issue with evening exercise. A 2018 study in the Journal of Sports Medicine discovered that some individuals are able to postpone sleep onset by engaging in high-intensity exercise within 1 hour of sleep.

However, there is a twist to this. The same study concluded that moderate-intensity exercise (such as brisk walking or light biking) did not affect sleep. As a matter of fact, it enhanced the quality of sleep among majority of participants.

The recommendations of the research:

• Do not do high-intensity intervals (HIIT, heavy lifting) after 8pm.
• No intense physical activity (running, jogging, lifting heavy objects): moderate exercise (walking, yoga, light jogging) can be done any time.
• Complete your exercise at least 90 minutes prior to going to sleep
• The Findings of the Greatest Importance: Consistency wins over Timing.

This is what all the individual studies are in agreement on:

The optimal exercise schedule is the time you will perform on a regular basis.

In 2022, a giant study in Obesity Reviews examined data on more than 50,000 individuals. The researchers found that timing had a small effect on outcomes. Consistency made a huge impact.

An individual who gets up to work out at 6am daily will have a better result than a different individual who gets up to work out at the ideal 2pm time but only exercises at 2pm twice a week.

This is similar to my own experience. I was only able to make it 2 weeks when I attempted to make myself indulge in a 5am routine (because morning is best). Once I had accepted that I was an evening person I started to exercise 5-6 days a week.

Takeaways: How to Select Your Time.

Step 1: Be Realistic with Your Schedule.

Ask yourself:

• Am I more energetic in the morning or evening?
• When do I normally have 30 60 minutes of free time?
• Is there any form of obligation (work, childcare) that I cannot alter? 

Frequently Asked (Questions with Research)

Q: Does a morning exercise with fasting help in weight loss better?

The study: In one study by the Journal of Clinical Endocrinology and Metabolism (2017), the researchers discovered that fasted mornings exercises enhanced the fat burning during the exercise. However, total 24-hour fat loss was similar to fed exercise. The difference was insignificant.

My opinion: You like working out in the morning fasted, go on. Give it away, if you despise it. Consistency matters more.

Q: Can evening exercises destroy my sleep?

The research: For most people, moderate evening exercise improves sleep. Some individuals could be delayed in sleep due to high-intensity evening exercise within a time span of 60 minutes before bedtime.

My advice: Have your workout finished at least 90 minutes before bed. Keep intensity moderate. You will probably get more sleep.

Q: Does it make any difference when I exercise during the day?

The study: A 2021 study in Nutrients established that the different lengths of exercises did not have any adverse effects. Your body adapts.

My advice: Do not worry about ideal consistency. Something is better than nothing.

Sources I Used for This Guide

I read or listened to the following sources. You can verify them yourself:

1. Medicine & Science in Sports & Exercise (2017) – Morning exercise and consistency

2. Journal of Physiology (2019) – Fasted morning exercise and fat oxidation

3. Hypertension (2018) – Morning exercise and blood pressure

4. Frontiers in Physiology (2019) – Time of day and strength performance

5. Sports Medicine (2018) – Evening exercise and sleep

6. Obesity Reviews (2022) – Consistency vs. timing

7. Journal of Clinical Endocrinology & Metabolism (2017) – Fasted vs. fed exercise

8. Nutrients (2021) – Varying exercise times

I also interviewed one certified strength coach (anonymous) and one physical therapist (name withheld for privacy).

About the author

Eisa Khan is a researcher and fan of fitness. He does not have a degree in exercise science. He studies, consults specialists and tries what he can on himself. He tells you what he learns, so that you need not go and do the homework. Get in touch with him via the Contact Page.

Last updated: 13 April, 2026