Unpacking the "Mind" and "Body" Pathways of the Antidepressant Effect of Qigong in Older Adults: A Pilot Study

The goals of the study are to explore the neurobiological mechanisms and cognitive benefits of qigong in older adults. The main research questions are: * Does 12-week qigong training lead to significant enhancement in serum adiponectin, serum BDNF and significant reduction in salivary cortisol? * Does 12-week qigong training bring significant improvement in global cognitive function? Participants are older adults aged 60 or above. They were randomly assigned to qigong training, mindfulness training, physical exercise training, or wait-list which all last for 12 weeks. Their changes before and after the 12-week period in depressive symptoms, neurobiological markers, and cognitive functions are assessed.