Effects of HIIT at different frequencies in an aquatic environment on mental health in multimorbid older people: A randomized clinical trial

da Silva VOS, Thirupathi A, Macedo RADS, Santos MF, Borba ACO, Gu Y, Gomes KM, Delevatti RS, Silveira PCL, da Silva LA

Question

Does aquatic HIIT frequency affect sleep, sleepiness, anxiety, and depression in older adults with multimorbidity?

Summary

Older adults with multimorbidity completed 12 weeks of aquatic HIIT either once or twice weekly. Twice-weekly training improved sleep quality, daytime sleepiness, anxiety, and depression scores, while once-weekly training did not show significant changes.

Methodology

Fifty-six older adults with multimorbidity were analyzed per protocol.
56 participants.
Water-based exercises.
Work intervals: 30 seconds.
Recovery: 30 seconds active recovery; 60 seconds between exercises.
Intensity: 80%-90% water-adjusted HRmax; Borg CR10 8-10.
40 minutes.
Once or twice weekly.
12 weeks.
Randomized comparative clinical trial
Sleep quality, Sleepiness, Anxiety, and Depression were tracked.

Outcomes

Sleep

Twice-weekly aquatic HIIT improved PSQI by about 49% and ESS by about 50%; once-weekly HIIT did not significantly change sleep outcomes.

G2 PSQI p=.032, ESS p=.041; G1 PSQI p=.079, ESS p=.231.

Improved

Anxiety

Anxiety decreased in the twice-weekly group but not the once-weekly group.

G2 p=.047; G1 p=.436.

Improved

Depression

Depression decreased in the twice-weekly group but not the once-weekly group.

G2 p=.017; G1 p=.652.

Improved

Insights

For this aquatic protocol, twice-weekly frequency appeared necessary for mental-health improvements.
Pool-based HIIT can use HR plus Borg targets when movement speed is self-generated against water resistance.

Limitations

No nonexercise control group.
Per-protocol analysis excluded inadequate adherence.
Participants and instructors were not blinded.
No stratification by specific multimorbidities.
No post-intervention weight measure.

Safety

No adverse effects were reported.