This article in American Journal of Physiology. Heart and Circulatory Physiology (2009, October; 297(4): H1314-8), by Kenta Yamamoto, Hiroshi Kawano, Yuko Gando, Mitsuru Higuchi, Motoyuki Iemitsu, Haruka Murakami, Michiya Tanimoto, Yumi Ohmori, Izumi Tabata, Motohiko Miyachi, and Kiyoshi Sanada, points out that "Flexibility is one of the components of physical fitness as well as cardiorespiratory fitness and muscular strength and endurance. Flexibility has long been considered a major component in the preventive treatment of musculotendinous strains. . . . Using a cross-sectional study design, we tested the hypothesis that a less flexible body would have arterial stiffening. A total of 526 adults, 20 to 39 yr of age (young), 40 to 59 yr of age (middle-aged), and 60 to 83 yr of age (older), participated in this study. Subjects in each age category were divided into either poor- or high-flexibility groups on the basis of a sit-and-reach test. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV). . . . In young subjects, there was no significant difference between the two flexibility groups. A stepwise multiple-regression analysis (n = 316) revealed that among the components of fitness (cardiorespiratory fitness, muscular strength, and flexibility) and age, all components and age were independent correlates of baPWV. These findings suggest that flexibility may be a predictor of arterial stiffening, independent of other components of fitness." [The following is a quote from text of article] " . . . we believe that flexibility exercise such as stretching, yoga and pilates would be integrated as new recommendation into the known cardiovascular benefit of regular exercise. However, although the present results are the first to provide evidence demonstrating that poor flexibility is associated with greater age-related arterial stiffening, the present cross-sectional study provided only associations among age, flexibility, and arterial stiffness. Intervention study is also needed to determine the cause-and-effect relationship between flexibility and arterial stiffness." See also news release from the American Physiological Society: A Simple Way for Middle Aged and Older Adults to Assess How Stiff their Arteries Are: Reach for Their Toes. Abstract: PubMed.
On October 22, YMN Daily contacted Dr. Kenta Yamamoto, who generously agreed to offer some additional insights:
"I think that autonomic nerves system is key point of mechanisms responsible for the relationship between flexibility and arterial stiffness.
I have a hypothesis that stretching exercise would change autonomic nerves system toward relaxing, resulting in a decrease in arterial stiffness.
If that is true, yoga also will contribute to reducing age-related arterial stiffening.
We are doing a stretching intervention study now."
- Kenta Yamamoto
