Effects of high-intensity interval training on depressive symptoms in Hong Kong community-dwelling older adults with mild to moderate depressive symptoms: a study protocol for a cluster randomized controlled trial.
Wang Y, Liang W, et al. • Frontiers in public health • 2026
This paper describes a protocol for a single-blinded, cluster-randomised controlled trial investigating the effects of HIIT on depressive symptoms, biomarkers, physical fitness, sleep quality, and quality of life in Hong Kong community-dwelling older adults with mild to moderate depressive symptoms.
Key Findings
Background
The study identifies a gap in the literature regarding HIIT's application for depressive symptoms in older adults.
High-intensity interval training (HIIT) has garnered increasing attention for its potential to improve both depressive symptoms and physical health.
The authors state that 'the application of HIIT to address depressive symptoms among older adults remains scarce.'
Exercise generally has been recognised as a readily available approach for reducing depressive symptoms.
Older adults with mild to moderate depressive symptoms are described as being at high risk of developing severe depression along with complications, disability, and mortality.
Methods
The trial is designed as a single-blinded, cluster-randomised controlled trial with three parallel groups and three assessment time points.
The three groups consist of a HIIT group, a Baduanjin Qigong control group, and a recreation workshop non-exercise control group.
Participants will be allocated in a 1:1:1 ratio across the three groups.
Assessments will occur at baseline, after completion of the 16-week intervention, and at a three-month follow-up.
Cluster randomisation will be used as the method of allocation.
Methods
The trial plans to enrol 144 eligible participants from 9 community centres across Hong Kong.
Participants will be community-dwelling older adults with mild to moderate depressive symptoms.
The 9 community centres serve as the clusters in the cluster randomisation design.
144 participants will be distributed across 9 clusters, suggesting approximately 16 participants per cluster.
The study is registered on ClinicalTrials.gov with identifier NCT06014294.
Methods
The primary outcome measure is self-reported depressive symptoms, with multiple secondary outcomes also planned.
Self-reported depressive symptoms constitute the primary outcome measure.
Secondary outcome measures include salivary cortisol described as 'a biomarker of depressive symptoms.'
Additional secondary outcomes include physical fitness, sleep quality, and quality of life.
The intervention duration is 16 weeks.
Conclusions
The study aims to determine whether HIIT produces greater improvements in depressive symptoms and health-related outcomes compared to Baduanjin Qigong and a non-exercise recreation workshop.
The study will assess 'whether older adults in the HIIT group could gain more improvement in depressive symptoms and other health-related benefits compared to the control groups.'
If HIIT demonstrates superiority, the authors suggest 'it could be prescribed as a new exercise regimen to benefit older adults with depressive symptoms in future studies.'
The authors argue that early intervention during mild to moderate stages of depressive symptoms 'is important to prevent further deterioration.'
The research findings are anticipated to 'have considerable impacts on the future prevention and treatment of mental disorders' and contribute to 'promoting healthy aging among Hong Kong older adults.'
What This Means
This paper describes the design and protocol for a clinical trial that has not yet reported results. The trial is testing whether high-intensity interval training (HIIT) — a form of exercise involving short bursts of intense effort — can reduce depressive symptoms in older Hong Kong adults who already experience mild to moderate depression. The researchers will compare HIIT to two control conditions: Baduanjin Qigong (a traditional Chinese mind-body exercise) and a non-exercise recreation workshop. A total of 144 participants from 9 community centres will take part in the 16-week program, with follow-up measurements taken three months after the intervention ends.
This research suggests that exercise, and HIIT in particular, may be a promising tool for addressing depression in older adults before it becomes severe. Measuring both self-reported mood and a biological stress marker (salivary cortisol), as well as physical fitness, sleep, and quality of life, allows the researchers to capture a broad picture of health effects. The inclusion of Baduanjin Qigong as a second active comparison group means the study can potentially tell us not just whether HIIT works, but whether it works better than another established form of exercise.
Because older adults with mild to moderate depression are at elevated risk of worsening mental health, disability, and even death, finding effective and accessible interventions at this early stage is important. This research suggests that if HIIT proves effective, it could represent a practical, scalable option that community health programs might use to help older adults maintain mental and physical wellbeing. However, since this paper only describes the study protocol and no results have been reported yet, no conclusions about HIIT's effectiveness can be drawn at this time.
Wang Y, Liang W, Duan Y, Lau W, Chan N, Yang S, et al.. (2026). Effects of high-intensity interval training on depressive symptoms in Hong Kong community-dwelling older adults with mild to moderate depressive symptoms: a study protocol for a cluster randomized controlled trial.. Frontiers in public health. https://doi.org/10.3389/fpubh.2026.1697763