The more flexible you are as you age, the longer you’re likely to live. That’s the conclusion of a new study that associated increased flexibility in middle age with lower odds of mortality over the next dozen or so years.
Claudio Gil Araújo, MD, PhD, the research director of the Exercise Medicine Clinic-CLINIMEX in Rio de Janeiro, who led the study, said his group was not surprised by the results. “We found what we expected. Reduced flexibility was related to poor survival,” he said.
The findings, published in the Scandinavian Journal of Medicine & Science in Sports, used data from 2087 men and 1052 women who underwent a medical-functional evaluation at CLINIMEX. They received a body flexibility score, called the Flexindex, based on range of motion in 20 movements in seven joints, with a minimum score of 0 and a maximum score of 80.
Among the 3139 participants, there were 302 deaths (9.6%) during a mean follow-up of 12.9 years, with cardiovascular diseases and cancer the most common underlying causes in men and women, respectively.
“The probability of death during nearly 13 years of follow-up was close to 1% when Flexindex scores exceed 49 for men and 56 for women,” Dr. Araújo told this news organization. “On the other hand, for men and women placed in the lower 10 percent of Flexindex scores, death rates were, respectively, 26.9% and 18.2%.”
Barry Franklin, PhD, director of preventive cardiology and cardiac rehabilitation at Corewell Health William Beaumont University Hospital in Royal Oak, Michigan, and a co-author of the new study, said men with the poorest flexibility were nearly twice as likely to die over the follow-up period than men with high flexibility. Women with the poorest flexibility were almost five times more likely to die than those with high flexibility.
Flexibility Assessment and Training
Dr. Araújo opened CLINIMEX in 1994, and since then, its staff of five physicians have evaluated more than 10,000 individuals using the Flexitest. Dr. Araújo has published two previous studies on flexibility. The first showed that the ability to rise from a sitting position on the floor is a strong predictor of longevity, and the second demonstrated that the inability to stand on one leg for at least 10 seconds is linked to an increased risk for death over 7 years.
Dr. Araújo and his colleagues believe the current study is the first to assess the association between levels of body flexibility and mortality. But the observational analysis was unable to establish causality, and therefore, they could not show a definitive mechanism to explain the association between low levels of flexibility and premature mortality.
The authors noted several limitations of their study. The participants were primarily affluent White people, and the researchers did not control for the time of day flexibility was measured or for variables such as diet and physical activity. They also acknowledged reduced flexibility may be a consequence of poor lifestyle habits rather than a causal risk factor for mortality.
Jonathan Bonnet, MD, MPH, an exercise expert at the Stanford Center on Longevity Lifestyle Medicine in California, said the researchers used a more robust evaluation of flexibility than a traditional sit-and-reach test. However, he expressed concern that the primary comparisons were of the upper and lower 10% of performers and that the average differences in Flexindex scores between people who died and those who survived were only a handful of points in an 80-point test.
“People who are not flexible probably have other health-related issues that limit their mobility and those who are very flexible are either genetically different from inflexible individuals or are doing something to maintain or increase their flexibility to a high level,” Dr. Bonnet said. “Not knowing how active or inactive people are at baseline when flexibility was assessed or over the duration of the study limits how confident we can be that flexibility is the cause of mortality.”
Dr. Bonnet, a member of the American College of Lifestyle Medicine, noted that the latest guidelines on physical activity from the US Department of Health and Human Services do not include recommendations on stretching, given the lack of data demonstrating its specific health benefits. While maintaining mobility and range of motion in joints is important for long-term health, he said the new study does not provide sufficient evidence to recommend stretching as a way to reduce mortality.
“Until there are more data that can show a cause-and-effect relationship with stretching and health outcomes, time is better spent doing aerobic and muscle-strengthening activities,” Dr. Bonnet said.
Dr. Franklin said future studies could better account for missing potential confounders like physical activity and whether individuals were taking protective medications, such as aspirin, cholesterol-lowering drugs, or beta-blockers. Studies also are needed to assess whether training-induced gains in flexibility are specifically related to increases in survival and whether their findings apply to people over the age of 65, he said.
The current findings “give us some additional ammo to say, ‘Wow, being more flexible may, in fact, improve long-term survival or outcomes’,” Dr. Franklin said. Regardless, flexibility still “improves quality of life, it improves balance and reduces the potential for falls, and all those things make it worthy of better recognition or appreciation by the general public and clinicians,” he added.
Dr. Araújo said he would like his research to influence people’s health. “While to exercise regularly is advisable, what really matters is to be physically fit and not only in aerobic or strength fitness but also in flexibility,” he said. “The study is adding a new and, I believe, important ‘relevant for survival’ label on flexibility assessment and training.”