PMID 32854688

Research
All papers

Effect of high-intensity interval training on cardiorespiratory fitness, physical activity and body composition in people with schizophrenia: a randomized controlled trial

Andersen E, Bang-Kittilsen G, Bigseth TT, Egeland J, Holmen TL, Martinsen EW, Stensrud T, Engh JA

Question

Does supervised treadmill HIIT improve cardiorespiratory fitness, physical activity, and body composition in people with schizophrenia compared with an active low-intensity gaming control?

Summary

In outpatients with schizophrenia, 12 weeks of supervised treadmill HIIT did not significantly improve VO2max, physical activity, sedentary time, or body composition compared with an active computer-gaming control. Adherence and valid VO2max testing were challenging. Exploratory analyses suggested staff physical-activity competence may have influenced outcomes.

Methodology

  • Eighty-two outpatients were randomized: HIIT n=43 and comparison n=39. Participants were adults aged 18-67 with DSM-5 schizophrenia spectrum disorder, IQ at least 70, and Scandinavian language ability. Most were on antipsychotic medication; mean BMI was about 29-30.
  • 82 participants.
  • Treadmill walking/running HIIT.
  • Work intervals: 4 min.
  • Recovery: 3 min.
  • Intensity: 85-95% maximum HR during intervals; about 70% maximum HR during active pauses.
  • 45 min.
  • 2.
  • 12 weeks.
  • Randomized controlled observer-blinded clinical trial
  • VO2max from modified Balke treadmill test with gas analysis, Pulmonary function and treadmill work capacity, Physical activity and sedentary time by ActiGraph, and Body composition by bioelectrical impedance were tracked.

Outcomes

VO2max and cardiorespiratory variables

No significant between-group or within-group differences were found in VO2max or cardiorespiratory variables. VO2max was 32.1 +/- 11 to 30.8 +/- 11 mL/kg/min in HIIT and 31.1 +/- 11 to 31.1 +/- 11 in comparison.

No clear change

Physical activity and body composition

No significant changes were found in physical activity, sedentary time, or body composition.

No clear change

Valid VO2max test completion

Only 21/43 HIIT participants and 26 comparison participants had valid VO2max tests at post-measurement.

Mixed

VO2max responder proportion

Forty-seven percent of HIIT participants and 27% of comparison participants had at least 5% VO2max increase.

Mixed

Staff competence subgroup fitness response

Exploratory analysis suggested HIIT led by PA-competent staff increased CRF compared with non-PA-competent staff: +2.4 +/- 4.5 vs -2.2 +/- 4.7 mL/kg/min, p=.010.

p=.010

Improved

Insights

  • A nominal HIIT protocol may fail to improve fitness if achieved intensity, adherence, or test validity are limited.
  • For populations with severe mental illness, staff skill and motivational support may be part of the effective intervention.
  • Avoid extrapolating from prescribed HIIT dose alone; report achieved intensity.

Limitations

  • Many invalid VO2max tests reduced power.
  • Only two sessions/week and incomplete interval intensity may have limited training stimulus.
  • Staff PA competence finding was exploratory/post hoc.
  • Clinical special population and supervised context limit generalizability.

Safety

  • No adverse events were found in the the paper.
  • High-intensity adherence was incomplete: 39.9% of intervals reached at least 85% maximum HR.