CrossFit

Timing is everything (part 2: exercise)

Meyken Houppermans
Founder and Head Coach
The time a day at which you work out determines the degree to which your muscles adapt to exercise and use oxygen for energy. How can that be explained?

Biological clock

As we explained in our article about Timing is everything (part 1: food): despite the fact that our daily lives are structured by a 24-hour time frame, some of us are more energetic and productive in the morning, while others flourish at night. This has everything to do with our biological clock.

Circadian rhythm

Our biological clock is the natural timing device that regulates our so-called circadian rhythms: natural physical, mental and emotional processes in our body in respond to light and dark (day and night). Circadian rhythms are also known as the sleep- wake cycle. Every cell, tissue, organ and muscle in our body has a biological clock, and all clocks are coordinated by acmaster clock in our brain that receives input from our eyes (light).

Circadian rhythms influence several processes in our bodycamong which hormone release, digestion and muscle’s metabolic response andenergy efficiency. Several factors such as a jet lag, evening shifts at work, bluelight from our phone and 24/7 light from buildings in our environment, can change circadian rhythms. These changes can have severe consequences: Sleepdisorders, obesity, diabetes type 2 and mental health issues and also lesscresults from our workouts (NIGMS, 2020).

Muscle clock

Our circadian clock and oxygen in our body work together inside our muscleccells to produce energy. The degree of synchronization of their work depends oncthe time of day. The more synchronized they are, the more efficient muscleccells are in their ability to adapt to exercise and to use oxygen for energy.And that seems to be during our ‘normal’ waking hours.  

When we work out we consume oxygen fast. We also run out of oxygen fast, so we need another source of energy to keep going. That dip in oxygen triggers specific proteins in our body that signal muscles to switch to sugar for energy.  

Messing up the muscle clock, for example by working out at unusual times, prevents our capacity to induce sugar consumption and produce lactic acid. Adjusting our working to our ‘natural’ rhythm and to the time a day can improve muscle function. Furthermore, improving our muscle clock can also contribute to the treatment of diabetes, since in this disease muscles fail to consume glucose(Peek et al, 2016). 

So in order to get the most out of a training session, adjust your planning to your natural rhythm: if you are a morning person you might want to workout in the morning, and if you are an evening person, a workout later during the day might be better. 

Create your own health!©