Question: Hi Bill, what’s your thoughts on post workout stretching?
Me: I don’t really have any. 
If you like it, do it. If you don’t, you don’t have to.
Follow-up Question: Would you say there are “real” benefits to post workout stretching such as recovery? It seems this is a controversial topic.
Me: Research is interesting in this regard. There are indications that post-workout stretching reduces peripheral blood flow, but it will increase blood flow AFTER you stretch (called a rebound effect). there’s also an indication that you’ll increase HRV/parasympathetic nervous system (PNS) influence as a long-term side effect over a period of days/months. (https://www.researchgate.net/publication/274517864_Acute_Changes_in_Autonomic_Nerve_Activity_during_Passive_Static_Stretching)
Here’s where I think there may a few catches.
What positions are you using to perform stretching?
We have research to support the fact that body postures influence the autonomic nervous system with certain postures being more favorable in producing a parasympathetic response (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2222597/)
How do you breathe when you stretch?
Manipulating breathing rhythm and duration of inhalation vs. exhalation can alter the autonomic nervous system as well. Even breathing through different nostrils (left more parasympathetic) can influence it. (https://cialoslowem.files.wordpress.com/2016/03/2006-physiology-of-longpranayamic-breathing-neuralrespiratoryelementsmayprovide.pdf)
What are you thinking when you stretch?
The human neocortex has the ability to anticipate and simulate the world around us. Depending on what you’re thinking, you can influence our normal stress response and shift the autonomic nervous system favorably toward parasympathetic dominance or sympathetic. (See Why Zebras Don’t Get Ulcers)
In what environment are you when you stretch?
Simply perceiving an exercise environment as more favorable may alter performance and mood. This, in turn, will alter your autonomic nervous system. (https://digitalcommons.ithaca.edu/cgi/viewcontent.cgi?article=1133&context=ic_theses)
Increased PNS activity/HRV appears to be a sign of more robust health. That’s all good. The question becomes is it just transient based on some of the above conditions? Does a short period of parasympathetic reactivation promote better health?
Want a fast way to drop heart rate to demonstrate how we can manipulate autonomics? Simply submerge your face in a bowl of cold water for about 30 seconds.
video courtesy of Adam Loiacono
So is it really the stretching or is it the fact that peripheral sensations due to position are the influence or is it the breathing or is it the environment? Maybe it’s the effect of increasing pain tolerance (an effect of stretching) that improves HRV/PNS effects. The brain works in mysterious ways.
I suppose the bottom line is…
If you like to stretch, then stretch.
If you don’t, don’t.
There are many ways to gain the proposed beneficial effects as indicated by research.
Get started on your pain-free comeback to the gym today
