Facilitated stretching is a part of almost every session of MET at our clinic. It seems the benefit of regular stretching may go beyond simply improving flexibility and may help reduce cardiovascular risk as well. Shinno et al. (2017) studied women who were asked to stretch 3 times per week, for 3 or 6 months. Participants were premenopausal, over 40yo and healthy i.e.:
- BMI in the healthy range,
- no neurological or physical diseases
- no lifestyle-related diseases e.g. hypertension, hyperlipidaemia
During the study each woman daily conducted 20-30 seconds of static stretches while standing, sitting, or lying for each of 15 muscle groups: ‘trapezius, arm flexors, deltoids, triceps, upper back muscles (trapezius and rhomboid), pectoralis major, latissimus dorsi, gastrocnemius, soleus, hip abductors, hip adductors, quadriceps, hamstrings, gluteus maximus, and the lower erector spinae. The stretching was performed at an intensity that participants rated as “somewhat heavy” to “heavy” with respect to perceived exertion (Borg Scale).
To see whether the stretching routine had any long-term effects on blood vessels flexibility (compliance), researchers measured an index called RH-PAT both before and after 3 or 6 months of stretching. RH-PAT is determined by:
- measuring normal arterial blood flow in the forearm, then
- inflating an upper-arm cuff to stop blood flow for 5 minutes, then
- releasing the cuff and measuring blood flow after cuff release.
- Calculating the ratio of arm blood flow before cuffing and after cuff-release
- This gives a ratio called the “reactive hyperaemia peripheral artery tonometry (RH-PAT) index”
RH-PAT is a “powerful predictor of all-cause and cardiovascular morbidity and mortality”. It can predict:
- endothelial dysfunction
- coronary artery disease & atherosclerosis
- microvascular dysfunction following sepsis
- coronary plaque formation
The arteries of healthy people are flexible/dilatable and will be able to dilate significantly after cuff-release, to deliver extra oxygen to oxygen-starved tissues. The HR-PAT index in healthy people is high i.e. > 1.48. Arteries of people with cardiovascular diseases on the other hand have difficulty dilating, and these people generally have a low HR-PAT i.e. < 1.48. In short a higher HR-PAT index is generally indicative of better arterial health, a lower HR-PAT index poorer arterial health.
So how did regular stretching effect participants artery’s ability to dilate (health)?
- all study participants had an RH-PAT index below 1.67 at the start of the study
- both 3 and 6 months of stretching improved RH-PAT index significantly
- a further 6-months of no-stretching saw RH-PAT index return to pre-intervention values
These results suggest that stretching may increase the compliance (flexibility) of arteries, reducing cardiovascular risk, and that regular stretching may lead to health benefits beyond increased muscle-flexibility. Importantly, once people stop stretching the cardiovascular benefits were slowly lost over 6 months. So, the old imperative idiom of ‘use it or lose it’ certainly applies to the cardiovascular benefits of stretching too.
Article Written + Submitted by:
Andreas Klein Nutritionist + Remedial Therapist from Beautiful Health + Wellness
P: 0418 166 269