Performance OUTPUT: better in the morning or in the evening?


After discovering what works best for myself, I wanted to discover the “why” of it, the analogy with other humans and the science behind it. 

I have done and read a lot of recent studies about what’s the thing or things that make people perform better in the morning or in the evening.

To start with, it is very important that we separate the concept of performance from the concept of well-being/weight loss-aesthetic goals. 


Performance goals have nothing to do with well-being state of mind or aesthetic goals.

This post is just about performance. ⬇️


On one hand, a researcher of the Weizmann Institute of science’s department, Dr Gad Asher, found out that “human exercise performance is better in the evening compared to the morning as athletes consume less oxygen aka energy, for the same intensity of exercise in the evening versus the morning”.

Asher’s research was done on mice first and then humans to study their exercise capacity at different intensities and regimens. Overall, the human study consumed less oxygen while exercising in the evening and took 20% longer to reach the point of exhaustion. 

On the other hand though, a study lead by the center of epigenetics and metabolism in California, found out that exercise seemed to be most beneficial on metabolism (fat burning and glucose breakdown) during late morning sessions. 


Furthermore, another study found out that since the core temperature is higher in the afternoon, humans function better in terms of muscle strength, flexibility, power output and endurance in the evening. 


Based on the data above, there is still a lot of work to do to find out the optimal timing for specific training sessions, not to mention the impact that hormonal changes have during the day, testosterone and insulin for example play a big role in the body in performance adaptation. 

The body produces more testosterone in the morning but the beneficial muscle hypertrophy is counteracted by the elevated cortisol level that leads to protein degradation. For this reason, it has been found that an increased resistance exercise that induce Testosterone is higher in the late afternoon/evening resulting in greater strength, muscle gains and power output.

And what about women? We are regulated by a different hormonal system and phases throughout the menstrual cycle that affect everything we do.

And what about sleep interference? For some people training in the evening is a blessing for quality sleep and for others in detrimental. 


To conclude though, from the latest studies and hormonal knowledge we have we can take some assumptions for endurance athletes: 

  1. Endurance athletes/triathletes can achieve more from hard sessions if they do them in the evening. Not only because of the less oxygen needed but also because the body has the chance to fuel enough during the day, the body is more flexible and responds better to higher resistance. 
  2. Endurance athletes who need to work on glucose breakdown and fat burning adaptation can work better in the morning. 
  3. Women must take in consideration the hormonal fluctuations during their cycle and adapt training intensity to the oestrogen cycle. 

As you can see from the above, there is a time for both morning and evening sessions in a training schedule, it all depends on your purpose for every session.

Athletes are advised then to coincide their specific resistance protocols sessions with performance times, therefore in the evenings. 

For women, it gets more complicated  but given that oestrogen peaks in the first half of the cycle, high intensity/speed/hard strength sessions are ideal and they can be performed either in the morning or in the evening. Well fuelled of course, remember that high intensity needs high GI fuel. 


After years of training and testing my adaptability, this is what works for me in terms of performance:

1. Endurance cycling: morning (well fuelled) in the follicular and luteal phase. 

2. Threshold/hard sessions: afternoon (well fuelled) in the follicular phase

3. Endurance running: afternoon/evening during the luteal phase (well fuelled) and early mornings in the follicular phase(80% of the time no fuel). 

4. Hard running: afternoon/evening in the follicular phase (well fuelled). 

5.Endurance Swimming: morning/lunch (well fuelled 2h before) 

6. Gym/CrossFit: afternoon (well fuelled)


the 2 variability in my schedule are always:

-the type of session and its purpose

-the phase of my menstrual cycle 


I always train on a full stomach unless I’m in the second week of the follicular phase where I can do short and low aerobic runs first thing in the morning (2 x week for one week only), all the rest is always fuelled.