PHYSIOLOGY OF RECOVERY

Adequate recovery is a key contributing factor to improved performance, lowers the risk for injury, and allows the human body proper time for it to heal itself so that’s it ready for the next training session, competition, or activity. If personal trainers understand the breadth and gravity of the physiology of post-exercise recovery, then they can help their clients prioritize it.

Here’s one of the best definitions of recovery I’ve come across in my Fit Pro career:

“Recovery from exercise refers to the time period between the end of a bout of exercise and the subsequent return to a resting or recovered state. It also refers to specific physiological processes or states occurring after exercise that are distinct from the physiology of either the exercising or the resting states.”

~Romero, Minson, & Halliwillcorresponding 2017

There are all sorts of recovery:

Mindset-based recovery

Active Recovery

Passive Recovery

There are lists upon lists of what you can coach your clients to do for recovery:

Flotation

Having Healthy Sleep and Sleep Habits

Eating nutritiously

Spending time with family, friends and loved ones

What are the physiological effects of post-exercise recovery?

The reason recovery is such a hot topic is because here’s what we know about it:

Proper post-exercise recovery allows for higher training volumes and intensities and offsets the deleterious impacts of overtraining.
One reason for this is that challenging exercise triggers skeletal muscle damage. For example, resistance exercise and high-intensity aerobic exercise impose disturbances of the skeletal muscle, specifically damaging the sarcolemma (these are contractile connective tissue and proteins). These perturbations result in a decreased ability for the human body to generate peak muscle forces until adequate repair of the skeletal muscle tissue is complete.
The damage to the skeletal muscle tissue limits the human’s body ability to transport blood glucose into the skeletal muscle cell which resultingly leads to a lowered capacity to replenish glycogen stores. Skeletal damage also leads to pain and soreness.

What happens during recovery after exercise?

The body is adapting to the stress associated with exercise, movement, and/or activity post-exercise. It replenishes muscle glycogen energy stores (here’s where adequate nutritional intake becomes paramount), and repairs the damaged skeletal muscle tissue  The recovery time allows the body to utilize the growth hormones that were released during the session for the repair.

The muscle fibers rebuild and protein synthesis also occurs. Exercise by nature physiologically stresses the body and releases cortisol. During recovery, the cortisol levels in the body wane and should return to balance, allowing for an internal environment for cellular repair to occur.
During exercise, the cardiovascular system is altered so that it can keep up with the activity the client or athlete is doing. Post-exercise, the cardiovascular system undergoes post-exercise hypotension, activation of a histamine signaling pathway, and postexercise vasodilation. Without proper recovery time, there could be potential consequences to the cardiovascular system because of these mechanisms. Recovery allows the cardiovascular system to go back to its original state prior to the exercise session so it too, is ready for the next round.
As you can see, the only reason that recovery is encouraged isn’t simply because it ‘feels good’ or because it’s a nice break to look forward to. There are physiological adaptations that the body undergoes during recovery that allows it to keep training and moving optimally and is a preventive factor of the detrimental impacts of overtraining.

References:

Dupuy, O., Douzi, W., Theurot, D., Bosquet, L., & Dugue, B. (2018). An evidence-based approach for choosing post-exercise recovery techniques to reduce markers of muscle damage, soreness, fatigue, and inflammation: A systematic review with meta-analysis.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5932411/
Romero, S.A., Minson, C.T., & Halliwill, J.R.  (2017). The cardiovascular system after exercise. Journal of Applied Physiology 122(4): 925–932.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5407206/