The effects of tai chi on sleep, metabolic health and cognitive function in older adults

Abstract

The willingness of older persons to exercise regularly is often deterred by an array of factors. Recognized by the older adults, Tai Chi, a mind-body exercise, may bring forward an option for them to gain health benefits of regular exercise. To compare the effects of Tai Chi and conventional exercise, which comprising no meditation element, on insomnia, impaired metabolic health and cognitive decline, three randomized controlled trials were conducted and specific brain activity profiles induced by these exercise modalities were identified in a pilot exploratory study.

The first study investigated the effects of Tai Chi on improving sleep in insomniac older adults. Participants were randomized to passive control (n=110), conventional exercise (n=105) and Tai Chi groups (n=105). Revealed by the pairwise comparisons between groups, both Tai Chi and conventional exercise improved actigraph-assessed sleep after the 12-week intervention relative to the passive control. Nevertheless, Tai Chi induced a more profound improvement in subjective sleep. The beneficial effects of both interventions remained persistent 24 months after intervention.

The second study investigated the effects of Tai Chi on metabolic risk factors in middle-age and older adults with central obesity. Participants were randomized to passive control (n=181), conventional exercise (n=181) and Tai Chi groups (n=181). Pairwise comparisons between groups showed that the waist circumference, body weight and body mass index were reduced concomitantly with an attenuated decrease in high-density lipoprotein-cholesterol relative to the passive control after 12 weeks of Tai Chi and conventional exercise interventions, respectively. The favorable changes of both interventions remained persistent 6 months after intervention.

The third study investigated the effects of Tai Chi on cognitive function in older adults with mild cognitive impairment. Participants were randomized to passive control (n=12), conventional exercise (n=12) and Tai Chi groups (n=10). Pairwise comparisons between groups showed that the improvements in global cognitive function relative to passive control were observed as early as 12 weeks after both interventions began, respectively. The improvement in global cognitive function provoked by Tai Chi was not only more evident than the conventional exercise counterpart, but also clinically significant. After the 24-week intervention period, both interventions led to clinically significant improvements in global cognitive function and enhancements in executive function, memory and attention. Tai Chi induced a more robust improvement in cognitive flexibility.

Revealed by electroencephalogram in the pilot exploratory study comparing the brain activity in individuals without exercise habit (n=6), with regular aerobic exercise (n=6) and regular mind-body exercise (n=6), the beta power in the temporal and right central regions of the brain and the alpha power in temporal, central and right central parietal regions of the brain was higher in individuals with regular aerobic exercise than their regular mind-body exercise counterparts under eye-open resting condition.

Collectively, Tai Chi reproduces the benefits of conventional exercise in the management of aging-related impairments in sleep, metabolic health and cognitive function, thereby presents a propitious alternative path to healthy aging. In addition, the brain activity profiles induced by mind-body exercise and aerobic exercise are distinct.