Studies have shown that Tai Chi and conventional exercise can modify the brain through distinct mechanisms, resulting in different brain adaptations. Therefore, it is conceivable to speculate that these two exercise modalities may have different effects on improving cognitive function. This study was a parallel group, assessor-blinded, pilot randomized controlled trial comparing the effects of Tai Chi and conventional exercise on improving cognitive function in older persons with mild cognitive impairment (MCI). A total of 34 adults aged ≥ 50 years with MCI were randomized (1:1:1) to the Tai Chi group (TC, n = 10, 3 sessions of 60-min Yang-style Tai Chi training per week for 24 weeks), conventional exercise group (EX: n = 12, 3 sessions of 60-min fitness training per week for 24 weeks), or control group (CON: n = 12, no intervention). Global cognitive function assessed by the Hong Kong version of the Montreal Cognitive Assessment (MoCA-HK) and performance in various cognitive domains were examined at baseline, and 12 and 24 weeks of the intervention. Both exercise groups showed improved global cognitive function as measured by MoCA-HK compared with the control group after 12 and 24 weeks of the intervention, (all P < 0.001). Only TC achieved clinically relevant improvement on global cognitive function at week 12. Both exercise groups achieved clinically relevant improvements at the end of the interventions at week 24. Compared with EX, TC exhibited greater improvements on global cognitive function indicated by MoCA-HK after 12 weeks of the intervention (P < 0.001) and cognitive flexibility indicated by part B/A ratio score of the Trail Making Test throughout the study (all P < 0.05). Both interventions were equally effective in improving the other examined cognitive domains. Further studies are needed to substantiate the superior long-term benefits of Tai Chi on global cognitive function compared with conventional exercise, and dissect the underlying mechanisms of the two exercises on improving cognitive domains and the corresponding brain adaptations. Trial registration: This study was registered at clinicaltrials.gov (Trial registration number: NCT04248400; first registration date: 30/01/2020).

Background: The World Health Organization physical activity guidelines recommend adults and older adults to accumulate at least 150–300 min of moderate or 75–150 min of vigorous aerobic-type physical activity weekly for health benefits including improvements of cognitive performance. However, the optimal exercise intensity and frequency for maximizing the cognitive benefits remain unclear.Purpose: We conducted a parallel, assessor-blinded, pilot randomized controlled trial to evaluate the effectiveness of different intensities and frequencies of the WHO-recommended minimal volume of aerobic-type physical activity on improving cognitive performance in middle-aged and older adults with mild cognitive impairment (MCI).Methods: Participants were randomly allocated to the stretching exercise control group (CON), once-a-week and thrice-a-week moderate-intensity walking groups (M1 and M3), and once-a-week and thrice-a-week vigorous-intensity walking groups (V1 and V3). Intervention duration was 12 weeks. The primary outcome was global cognitive performance assessed by the Hong Kong version of Montreal Cognitive Assessment. Secondary outcomes were self-report and objective cognitive performances, mental health, sleep quality, and cardiorespiratory fitness.Results: Thirty-seven participants completed the study (CON: n = 7, M1: n = 7, M3: n = 7, V1: n = 8, V3: n = 8). Participants in all four walking exercise groups demonstrated significant improvements in global cognitive performance assessed by the Hong Kong version of the Montreal Cognitive Assessment after the intervention when compared to CON (p &lt; 0.001). The walking exercise interventions also significantly mitigated the anxiety severity (p &lt; 0.005) and improved the cardiorespiratory fitness (p &lt; 0.05) of the participants in the walking exercise groups.Conclusion: 150-min moderate- or 75-min vigorous-intensity walking exercise performed once- or thrice-weekly showed similar effects on improving cognitive performance in middle-aged and older adults with MCI. The 12-week walking exercise interventions also reduced anxiety severity and improved cardiorespiratory fitness of the participants.Clinical Trial Registration:clinicaltrials.gov, identifier NCT04515563

The optimal intensity of physical activity for alleviating depression in middle-aged and older adults remains unclear. The World Health Organization (WHO) physical activity guidelines recommend adults and older adults to accumulate at least 150-300 minutes of moderate or 75-150 minutes of vigorous aerobic-type physical activity weekly or an equivalent combination of both for health benefits including reduced risk of depression. This parallel, assessor-blinded, pilot randomized controlled trial preliminarily compared the effectiveness of the minimal volume of aerobic-type physical activity at different intensities as recommended by WHO (150 minutes of moderate walking exercise and 75 minutes of vigorous walking exercise weekly) on alleviating depression in middle-aged and older adults. Thirty-five participants were randomized to the control group (CON), moderate walking exercise group (MOD), or vigorous walking exercise group (VIG). The exercise frequency was three times a week and the intervention duration was 12 weeks. The primary outcome was the severity of depression assessed by Beck Depression Inventory. Secondary outcomes included severity of anxiety, sleep quality, quality of life, and cardiorespiratory fitness. Thirty participants completed the study (CON: n = 10, MOD: n = 10, VIG: n = 10). Participants in both MOD and VIG had significantly decreased depression severity after the intervention compared to CON (both p < 0.001). There was no significant difference between MOD and VIG (p = 0.92). Both MOD and VIG interventions also mitigated anxiety severity, improved quality of life and cardiorespiratory fitness. The minimum volume of walking exercise at either moderate or vigorous intensity was found to alleviate depression in middleaged and older adults.Trial registration: ClinicalTrials.gov identifier: NCT04403373. Highlights. The 12-week 150-minute moderate walking exercise and 75-minute vigorous walking exercise (the minimal weekly volumes of aerobic-type physical activity recommended by WHO guidelines) similarly reduced the severity of depression in middle-aged and older adults. . The 12-week walking exercise interventions significantly reduced anxiety severity concomitant with improved quality of life and cardiorespiratory fitness in middle-aged and older adults with depression.

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ObjectiveTo determine and compare the dose–response effects of exercise and caloric restriction on visceral adipose tissue in overweight and obese adults, while controlling for the weekly energy deficit induced by the interventions.MethodsPubMed, Embase, CINAHL and Web of Science were searched for randomised controlled trials comparing exercise or caloric restriction against eucaloric controls in overweight or obese adults. The primary outcome was the change in visceral fat measured by CT or MRI. Meta-analyses and meta-regressions were performed to determine the overall effect size (ES) and the dose–dependent relationship of exercise and caloric restriction on visceral fat. Heterogeneity, risk of bias and the certainty of evidence were also assessed.ResultsForty randomised controlled trials involving 2190 participants were included. Overall, exercise (ES −0.28 (−0.37 to −0.19); p<0.001; I2=25%) and caloric restriction (ES −0.53 (−0.71 to −0.35); p<0.001; I2=33%) reduced visceral fat compared with the controls. Exercise demonstrated a dose–response effect of −0.15 ((−0.23 to −0.07); p<0.001) per 1000 calories deficit per week, whereas the effect of caloric restriction was not dose-dependent (ES 0.03 (−0.12 to 0.18); p=0.64). Most of the studies showed a moderate risk of bias.ConclusionsThese findings support the dose–dependent effects of exercise to reduce visceral fat in overweight and obese adults. Caloric restriction did not demonstrate a dose–response relationship, although this may be attributed to the smaller number of studies available for analysis, compared with exercise studies.PROSPERO registration numberCRD42020210096.