Is flexibility linked to arterial stiffness?

Key numbers

How flexibility and arterial stiffness were measured

Yamamoto and colleagues (2009) studied 526 adults in three age groups: young (20 to 39), middle-aged (40 to 59) and older (60 to 83). Within each group, people were split into poor-flexibility and high-flexibility groups by a sit-and-reach test.

Arterial stiffness was measured as brachial-ankle pulse wave velocity (baPWV), how fast the pulse travels between the arm and the ankle; a higher value means stiffer arteries. The study looked at everyone at one point in time, testing the idea that a less flexible body would have stiffer arteries.

What the cross-sectional link looked like

In young adults there was no significant difference between the two flexibility groups. In middle-aged adults, baPWV was 1260 versus 1200 cm/s (the study's unit) in the poor- and high-flexibility groups. In older adults it was 1485 versus 1384 cm/s.

In a regression analysis of 316 participants, cardiorespiratory fitness, muscular strength, flexibility and age were each independently related to baPWV. The authors suggested flexibility may relate to arterial stiffening independently of other parts of fitness. Because everyone was measured once, this is an association; it does not show that poor flexibility causes stiffer arteries.

What stretching programs were linked to

Kato and colleagues (2020) pooled trials, randomized and non-randomized, published up to January 2020 that compared a stretching program with no exercise training in middle-aged and older adults. Of 69 trials found, eight were analyzed, with 213 people in total. The outcomes were arterial stiffness, the function of the blood vessel lining, and heart rate and blood pressure.

Stretching significantly reduced arterial stiffness (standardized mean difference minus 1.00, 95 percent CI minus 1.57 to minus 0.44) and improved blood vessel lining function (standardized mean difference 1.15, 95 percent CI 0.26 to 2.03). Resting heart rate fell by a mean of 0.95 beats per minute and diastolic blood pressure by a mean of 2.72 mm Hg.

This is a small, mixed evidence base about stretching programs over time. It does not show that a single stretch has the same effect, and it does not make any flexibility test, including the Systematic Toe Touch, a measure of blood vessel health.

The evidence

Each cited source is labeled according to how it supports the particular claim on this page. Direct test evidence, underlying-capacity findings and population reference values are distinguished from Systematic-defined protocols and standards. Historical development notes are retained internally rather than presented as public evidence. A study of an underlying capacity is never presented as validation of the Systematic test itself.

• Underlying-capacity evidence New source

  Yamamoto et al. (2009). Poor trunk flexibility is associated with arterial stiffening. American journal of physiology. Heart and circulatory physiology.

  What it found. Among 526 adults measured once, poor sit-and-reach flexibility went with higher baPWV in middle-aged and older groups, with no significant difference in young adults.

  What it does not show. It does not show cause. Sit-and-reach is not the Systematic Toe Touch, and a Toe Touch score is not a vascular-health measure.

  PubMed 19666849

• Underlying-capacity evidence New source

  Kato et al. (2020). The Efficacy of Stretching Exercises on Arterial Stiffness in Middle-Aged and Older Adults: A Meta-Analysis of Randomized and Non-Randomized Controlled Trials. International journal of environmental research and public health.

  What it found. Across eight trials (213 people), stretching programs reduced arterial stiffness and improved blood vessel lining function in middle-aged and older adults.

  What it does not show. A small, mixed trial base; it does not make a flexibility test a vascular diagnostic or show that one stretch reproduces a training effect.

  PubMed 32764418