PMID 41580784

Research
All papers

Effects of cycling high-intensity interval training on body composition and cardiorespiratory fitness in adults: a systematic review and meta-analysis

Cheng H, Song S, Shu H, Li H, Tao M, Liu B

Question

How does cycling HIIT compare with moderate-intensity continuous training for body composition and cardiorespiratory fitness in adults?

Summary

This meta-analysis of adult randomized trials found that cycling HIIT produced small average improvements in BMI and VO2peak compared with moderate-intensity continuous training, but did not significantly change body fat, fat mass, or lean mass overall. Effects varied strongly by population and protocol.

Methodology

  • Adults aged 18-60 across cycling HIIT randomized trials, including obese, sedentary, and clinical populations
  • 527 participants.
  • Cycling.
  • Work intervals: Varied by study, including 10-second sprints, 30-second intervals, and 4-minute intervals.
  • Recovery: Varied by study.
  • Intensity: HIIT defined as 80-100% VO2peak or maximum heart rate.
  • Varied; examples ranged roughly 20-60 minutes.
  • 3-5 sessions per week.
  • 2-24 weeks.
  • Systematic review and meta-analysis of randomized controlled trials
  • BMI, Body fat, Fat mass, and Lean mass were tracked.

Outcomes

BMI

Cycling HIIT slightly reduced BMI compared with MICT overall, with stronger benefit in obese subgroup and opposite direction in disease subgroup.

Overall SMD about -0.24 to -0.25, 95% CI about -0.45 to -0.05, P about 0.012-0.014; high heterogeneity I2 about 78-80%

Improved

Body fat

No significant overall body-fat effect.

SMD about -0.16 to -0.17, P = 0.160

No clear change

Fat mass

No significant overall fat-mass effect.

SMD about -0.18 to -0.19, P = 0.134

No clear change

Lean mass

No significant overall lean-mass effect.

SMD about -0.10 to -0.11, P = 0.461

No clear change

VO2peak

Cycling HIIT modestly improved VO2peak compared with MICT overall.

SMD about 0.25 to 0.26, 95% CI about 0.07 to 0.44, P = 0.007; I2 about 82-83%

Improved

Insights

  • Cycling HIIT evidence supports small average VO2peak benefits over MICT, but protocols are heterogeneous.
  • Body composition effects are not uniformly superior to MICT and may depend on obesity status and diet.
  • The review's clinical suggestions emphasize screening and modified progression in comorbid populations.

Limitations

  • High protocol and population heterogeneity.
  • Sex-stratified analyses were not possible.
  • Dietary confounding across included trials.
  • Allocation concealment and blinding were limited in many trials.
  • Subgroup findings may be driven by few studies.

Safety

  • The meta-analysis did not summarize adverse events, injuries, adherence, or tolerability from included trials as safety outcomes. It did report 527 completers across included RCTs and recommended pre-exercise risk screening, lower-intensity progression, close monitoring, and caution to avoid exercise-related adverse events in people with obesity plus comorbidities such as diabetes or fibromyalgia.