Low-volume sprint interval training improves aerobic capacity as much as moderate continuous endurance training, with far less exercise volume
Participants
n=318 in 16 randomised controlled trials (17 effects); mean 18.7 ± 5.1 participants per trial; age 23.5 ± 4.3 years; healthy, young.
Key Findings
SIT (repeated 30-s "all-out" efforts) had a small-to-moderate effect on aerobic capacity overall (Cohen's d 0.32, 95% CI 0.10-0.55), an aggregate improvement of ~3.6 mL·kg⁻¹·min⁻¹ (~8%).
Versus no-exercise controls: moderate-to-large effect (d 0.69, 95% CI 0.46-0.93).
Versus endurance-training controls: no difference (d 0.04, 95% CI −0.17 to 0.24) — SIT was as effective as continuous moderate-intensity training with a reduced volume of activity.
Practical Application
Across 16 RCTs (n=318 healthy young people), sprint interval training raised aerobic capacity by ~3.6 mL·kg⁻¹·min⁻¹ (~8%) and matched continuous moderate endurance training (d 0.04) with a much lower exercise volume — a time-efficient way to build aerobic fitness when time is short.
Inference, not tested here: keep sport-specific endurance where a race demands volume; SIT is efficient, not a full replacement for trained athletes.
Limitations
Healthy young, largely non-athlete samples; small individual trials.
All-out sprints are strenuous and may not suit all populations.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from B+: meta-analysis of 16 RCTs, mostly small trials (mean 18.7 participants each)
Content correction 2026-09-27
"Mixed RCT/non-RCT designs, modest n" -> 16 RCTs, n=318 (per the abstract); level B+ -> A- (meta-analysis of mostly small RCTs, per rubric); tier "mixed" -> Tier 0-1 (healthy young people).
"~20–30 s max efforts with full recovery" -> the abstract's repeated 30-s all-out efforts (recovery not stated in the abstract).
Added the abstract's effect sizes (d 0.32 overall, 0.69 vs no exercise, 0.04 vs endurance training; ~3.6 mL·kg⁻¹·min⁻¹, ~8%); "not a full replacement" labelled as inference; Sport "conditioning" -> "general".