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.

Inclusion Criteria:

• 60 years or older;
• With mild or severer levels of depressive symptoms as indicated by the Geriatric Depression Scale (GDS-8) scores of 5 or above, or Depression Anxiety and Stress Scale-21 (DASS-21) depression subscale scores of 4 or above
• Self-identified as physically stable and without life-threatening diseases.

Exclusion Criteria:

• With a history of practicing or receiving training of any form of mind-body or regular exercises (including tai chi, yoga, and qigong, or regular physical activity > 3 times/week) during the month prior to study enrollment
• Having changed medications or the dose of medications prescribed for their health condition in the month prior to study enrollment
• With severe cognitive or language impairment as defined as a score of less than 21 on Montreal Cognitive Assessment (MoCA-5min)
• Undergoing electroconvulsive therapy, psychotherapy, or psychoeducation for a psychological or psychiatric condition
• Unable to demonstrate satisfactory standing balance.