Effects of High-Intensity Interval Training on Depressive Symptoms in Hong Kong Older Adults

Effects of High-Intensity Interval Training on Depressive Symptoms in Hong Kong Older Adults With Mild and Moderate Depression: A Cluster-Randomized Controlled Trial

Depression in later life is a common health problem in aging societies. It is associated with poor quality of life, and increased risks of morbidity and mortality. People with severe depression may develop serious psychotic symptoms (e.g., delusions) and have higher mortality and disability than those with mild and moderate depression.

Traditional moderate-intensity continuous training (MICT) (e.g., Baduanjin Qigong) has proved to be effective in preventing and alleviating depressive symptoms among older adults. However, older adults with mental illnesses have poorer engagement and compliance with MICT programs. In recent years, as a novel type of exercise, high-intensity interval training (HIIT), which includes repeated bouts of high-intensity effort followed by varied recovery times, appears to be a promising approach for overcoming limitations in traditional MICT programs.

Considering there is little evidence of HIIT benefits related to older adults with depression, the current study aims to evaluate the effectiveness of a 16-week HIIT intervention on depressive symptoms and other health-related outcomes among Hong Kong Chinese older adults.

The study will be a cluster randomized controlled trial (CRCT) with three groups and three times repeated measures. Data will be collected in a pretest, post-test, and three months after the intervention. The eligible community elderly centers will be randomly distributed into one of three groups in a ratio of 1:1:1. The participants recruited and meeting the screening criteria will receive a 16-week HIIT intervention or Baduanjin exercise or recreation workshop. The intervention effects will be evaluated on depressive symptoms, concentration of salivary cortisol, sleep quality, quality of life, and physical fitness.

Inclusion Criteria:

• 60 to 74 years at the start date of the project
• Chinese version of Geriatric Depression Scale (GDS-C) scoring 5-11 (i.e., mild to moderate level of depressive symptoms)
• Passing the PAR-Q plus screening or with the physician's approval for readiness to participate in high-intensity exercise
• Above the average level of 2-mins stepping showing competent aerobic fitness
• No restriction on physical mobility
• No cognitive impairment, as determined by the Chinese version of the Mini-Mental Status Examination (i.e., score < 24)
• No previous substantial experiences in practicing HIIT or Baduanjin Qigong. The written informed consent form will be collected from each participant

Exclusion Criteria:

• Severe chronic disease restricting high-intensity exercise
• Having cognition impairment regarded by specialists