The Clinical Utility of Neuromotor Exercise as Antihypertensive Lifestyle Therapy

Hypertension Is a Prevalent Public Health Problem The American College of Cardiology (ACC) and American Heart Association (AHA) recently redefined hypertension to a lower blood pressure (BP) threshold of 130 mm Hg for systolic BP (SBP) or 80 mm Hg for diastolic BP (DBP) than the older Joint National Commission 7 (JNC7) criteria of 140/90 mm Hg (1,2). Now approximately 50% of adults in the United States are classified as having hypertension. The authors of the ACC/AHA recommendations emphasized that for the approximately 35 million U.S. adults who were newly diagnosed with hypertension according to these lower BP criteria, most of them could treat their hypertension with nonpharmaceutical therapies, such as exercise, which is one of the most effective lifestyle therapies for hypertension because it lowers BP 5 to 8 mm Hg (2). The New American College of Sports Medicine Exercise Recommendations for Adults with Hypertension Professional organizations throughout the world recommend moderate intensity aerobic exercise 5 to 7 d·wk−1 as the gold standard type of exercise to prevent and treat hypertension supplemented by resistance exercise 2 to 3 d·wk−1 (3). However, only approximately 23% of U.S. adults with hypertension adhere to these exercise recommendations (4). Of note, over the last 5 years, an increasing amount of scientific evidence has emerged on the BP benefits of other exercise modalities that include resistance and concurrent exercise (i.e., aerobic and resistance exercise combined) (5,6). In 2018, the Physical Activity Guidelines Advisory Committee (PAGAC) published its scientific report after reviewing a voluminous literature on the health benefits of physical activity published since the 2008 PAGAC Scientific Report (7,8). The American College of Sports Medicine (ACSM) then summarized the key findings in the 2018 PAGAC Scientific Report on exercise and hypertension in a new pronouncement entitled, “Physical Activity to Prevent and Treat Hypertension,” and followed the pronouncement with a blog that updated the exercise and hypertension recommendations of the College (9). These new exercise recommendations are framed by the Frequency, Intensity, Time, and Type (FITT) principle of exercise prescription (10) (Table). ACSM no longer recommends aerobic exercise as the sole primary modality of exercise to prevent and treat hypertension. Instead, aerobic or resistance exercise alone or combined (i.e., concurrent exercise) are recommended as viable antihypertensive lifestyle therapies. Individuals with hypertension are recommended to perform moderate intensity aerobic and/or resistance exercise on most, preferably all, days of the week for a total time of 90 to 150 min·wk−1 or more. Accordingly, the new ACSM recommendations offer more variety and attractive exercise options in less time that hopefully will translate to better exercise adherence for adults with hypertension.Table: The new ACSM FITT recommendations for hypertension.Neuromotor Exercise as Antihypertensive Lifestyle Therapy Evidence to Support the Overall Antihypertensive Effect Is Promising Currently, yoga and Tai Chi are the two primary neuromotor exercise options in the United States that are gaining popularity. The prevalence of practicing yoga and Tai Chi has increased from among 5.8% of the U.S. population in 2002 to 14.7% in 2017 (11). Yoga was developed approximately 5000 years ago in India as a holistic practice to improve well-being on physical, mental, emotional, and spiritual levels (12). Meanwhile, Tai Chi was developed approximately 400 years ago in China as a martial art (13). Even though the actual practice of yoga and Tai Chi are very different, they can both be generalized into physical movement, breathing techniques, and mental relaxation in modern day practice. In recent years, yoga and Tai Chi have attracted attention in the scientific community because of their numerous health benefits, including lower BP. For example, meta-analyses have shown that yoga lowered SBP 4 to 10 mm Hg and DBP 4 to 7 mm Hg (14–16); meanwhile, Tai Chi lowered SBP 12 to 15 mm Hg and DBP 4 to 6 mm Hg (17,18). However, despite this promising evidence, professional organizations that include the PAGAC, ACSM, and AHA are reluctant to recommend yoga and Tai Chi as primary antihypertensive exercise options alongside aerobic and resistance exercise (2,8,10). This reluctance is partially because the evidence to guide the clinical use of yoga and Tai Chi to prevent and treat hypertension is not of good quality (8,10). New and Emerging Research to Guide the Clinical Use of Yoga and Tai Chi to Prevent and Treat Hypertension In any exercise intervention study, the BP response to exercise is influenced by multiple factors simultaneously. These factors include subject characteristics, such as BP status; study design methods, such as the BP measurement procedures; and exercise intervention features, such as the FITT (19). Of note, in addition to the FITT of yoga and Tai Chi practice, there are instructional methods to consider that also may affect the BP response, such as the combinations of physical movement, mental relaxation, and breathing techniques, as well as the credential of the instructors. Encouragingly, there is emerging evidence to guide the clinical use of yoga and Tai Chi to prevent and treat hypertension. After the release of the 2018 PAGAC Scientific Report, we conducted the largest meta-analysis to date on the antihypertensive effects of yoga that included more than 3500 participants and 56 yoga interventions. In addition, we examined the influence of potential moderators, such as subject characteristics, study methods, and exercise intervention features, on the BP response to yoga in multimoderator regression models. We found that, on average, yoga was practiced approximately five sessions per week for approximately 60 min per session for ~13 wk. Yoga was most effective among adults with hypertension based on the JNC7 BP classification with BP reductions of SBP approximately 9 mm Hg/DBP approximately 5 mm Hg among adults with hypertension, followed by SBP approximately 5 mm Hg/DBP approximately 3 mm Hg among adults with prehypertension; and SBP approximately 3 mm Hg/DBP approximately 2 mm Hg among adults with normal BP (20). In the additive model that represents the largest potential BP reductions that could result from yoga, we found that when yoga was practiced three sessions per week, emphasizing both breathing techniques and meditation/mental relaxation, it elicited BP reductions as large as SBP approximately 11 mm Hg/DBP approximately 6 mm Hg among adults with hypertension, doubling the BP reductions resulting from yoga practice that did not specifically emphasize these features of SBP approximately 6 mm Hg/DBP approximately 3 mm Hg (20). With similar meta-analytical methods, we conducted another meta-analysis which is the largest to date on the antihypertensive effects of Tai Chi that included more than 3200 subjects and 31 Tai Chi interventions. On average, Tai Chi was practiced approximately four sessions per week for approximately 60 min per session for approximately 22 wk. We found that, similar to yoga and other exercise modalities recommended to prevent and treat hypertension, Tai Chi was most effective among adults with hypertension based on the JNC7 BP classification with BP reductions of SBP approximately 14 mm Hg/DBP approximately 6 mm Hg among adults with hypertension, followed by SBP approximately 11 mm Hg/DBP approximately 5 mm Hg among adults with prehypertension; and SBP approximately 8 mm Hg/DBP approximately 3 mm Hg among adults with normal BP. Interestingly, we found that Tai Chi interventions published in Chinese language journals were twice as effective in lowering BP as those published in English language journals. However, even the more conservative estimation based on Tai Chi interventions published in English language journals showed that Tai Chi can result in clinically meaningful BP reductions as large as SBP approximately 10 mm Hg/DBP approximately 4 mm Hg among adults with hypertension. The BP reductions of these magnitudes that result from yoga and Tai Chi practice rival or exceed those reported from aerobic, resistance, and concurrent exercise (see Fig.) (5,6,21,22). Findings from our meta-analyses not only confirmed the results from previous meta-analyses that yoga and Tai Chi can result in clinically meaningful BP reductions but also may guide the clinical use of yoga and Tai Chi to prevent and treat hypertension. For example, both breathing techniques and meditation/mental relaxation should be specifically emphasized during yoga practice to maximize the BP benefits.Figure: The greatest potential blood pressure reductions following aerobic, resistance, concurrent, yoga, and Tai Chi exercise training among adults with hypertension (adapted from 6, 7, 20, 21, 22).Neuromotor Exercise to Prevent and Treat Hypertension in the Future The expansion of the 2019 ACSM FITT recommendations for hypertension delivered a valuable public health message by providing adults with hypertension as many evidence-based exercise options as possible. In line with this public health message, neuromotor exercises, such as yoga and Tai Chi, are promising candidates to be considered as exercise options to prevent and treat hypertension in addition to aerobic and resistance exercise alone or combined due to newer and high-quality evidence we have overviewed in this commentary. Therefore, health care and exercise professionals should consider recommending yoga and Tai Chi to their patients and clients with hypertension, especially for those who prefer neuromotor exercise, or for those who are resistant or unable to engage in aerobic and resistance exercise for whatever reason. However, to truly promote the use of yoga and Tai Chi alongside aerobic and resistance exercise, there are clinically important questions that remain to be answered. For instance, what is the optimal combination of FITT and instructional methods of yoga and Tai Chi practice that can maximize the magnitude of the BP reductions? Can a single session of yoga and Tai Chi elicit immediate BP reductions that can persist for up to 24 h, termed postexercise hypotension? Eventually, additional randomized controlled trials that directly compare the antihypertensive effects of yoga and Tai Chi to aerobic and resistance exercise alone or combined while matching the FITT of different exercise modalities are needed to better inform the evidence-based exercise prescription recommendations for hypertension.