The Effects of an 8-Week Hatha Yoga Intervention on Executive Function in Older Adults

Yoga is a commonly practiced, mind–body activity that has components centering on meditation, breathing, and postures. In recent U.S. surveys of adults, 7.5% reported having used yoga at least once in their lifetime and 3.8%–5.1% reported having used it in the previous 12 months (1,2). The use of yoga and other complementary and alternative medicine therapies is becoming increasingly popular, especially among older adult populations who use these alternative therapies for aging-related chronic conditions such as back pain, arthritis, anxiety, depression, and cancer (3–6). Although yoga practice involves physical postures that mimic stretching, balance, and strength exercises, which result in physical benefits (7), it also includes an active attentional component of breathing and meditation practice. Given the age-related declines in cognitive function (8), little is known about the potential of yoga in maintaining or enhancing cognitive function in older adults. A considerable corpus of research exists that has extensively examined the effects of physical activity on cognition and executive functions. However, majority of these studies have examined the role of aerobic training. Colcombe and Kramer (9) in their meta-analysis reviewed randomized controlled trials (RCTs) conducted with sedentary healthy older adults and found that executive control processes (g = 0.68, p < .05) showed the largest benefit from aerobic fitness training. More recently, Smith and colleagues (10) conducted a meta-analysis to examine this relationship and reported that individuals randomly assigned to receive aerobic exercise training demonstrated modest improvements in executive function (g = 0.123, p < .018) and working memory (g = 0.128, p < .026). Regardless of the methodological differences, both these meta-analyses suggest that participation in aerobic physical activity can help improve cognitive function. However, compared with this extensive body of work on aerobic training and cognition, far fewer scientific studies or RCTs have examined movement-based embodied contemplative practices such as yoga (11–14) or tai-chi (15). Oken and colleagues (12) conducted a RCT examining the effects of yoga on cognition in healthy older adults, but found no relative improvements in cognitive function. The authors acknowledged two major reasons that explain these null findings: (i) recruitment of physically active seniors that may have resulted in a ceiling effect and (ii) the dose of exercise that was one session per week is lower compared with more frequent sessions employed in other successful RCTs (9,10). More recently, Hariprasad and colleagues (14) conducted a 6-month RCT with residents of elderly homes and found significant cognitive improvements in attention and processing speed, verbal and visual memory, working memory, and inhibitory control. The authors acknowledged the lack of an active control group, high dropout rate, and the need to examine effects of yoga on community-dwelling older adults. Given the paucity of yoga–cognition RCTs and to address limitations of previous studies, the purpose of this RCT was to examine the effects of an 8-week Hatha yoga intervention on executive function in community-dwelling older adults. We recruited sedentary healthy older adults and structured the dose of exercise to match the physical activity literature with training sessions held 3×/week. We also used three established measures of executive function that have been extensively used in physical activity research: the task switching paradigm (16), the n-back task (17,18), and the running memory span task (19). The primary outcomes were mean reaction time (RT) and accuracy (AC) scores on the three executive function measures. We hypothesized that regular, structured Hatha yoga practice, which included components of physical movements, breathing, and meditation, would lead to significant improvements on executive function measures following the 8-week trial in a sample of sedentary healthy community-dwelling older adults.