Sprint exercise snacks: a novel approach to increase aerobic fitness.
Level 2 - randomized trial
Individual randomized trial
PubMed 30847639 · doi:10.1007/s00421-019-04110-z
What was done
Twenty-eight healthy, inactive young adults (mean age ~22 years, baseline VO2 peak ~35 ml/kg/min) were randomly assigned to complete 18 training sessions over 6 weeks of either sprint snacks (SS; n = 12, 7 females) or traditional sprint interval training (SIT; n = 16, 7 females). The SS protocol involved three 20-second all-out cycling bouts separated by 1 to 4 hours of rest spread throughout the day. The SIT protocol involved three 20-second bouts interspersed with 3 minutes of rest within a single 10-minute session. The primary outcome was cardiorespiratory fitness (VO2 peak); secondary outcomes were a 150 kJ cycling time trial and exercise enjoyment.
What was found
Absolute VO2 peak increased by ~4% in the SS group and ~6% in the SIT group (main effect of time P = 0.002) with no significant difference between groups (group by time interaction P = 0.52). Performance in the 150 kJ cycling time trial improved by ~9% in SS and ~13% in SIT (main effect of time P < 0.001) with no difference between groups (group by time interaction P = 0.36). Numerical results for exercise enjoyment were not reported in the abstract.
Why it matters
This study indicates that spreading brief high-intensity sprints throughout the day can produce aerobic fitness and exercise performance gains comparable to standard condensed sprint interval training.
Limits
The sample size was small (n = 28 total across two arms), limiting statistical power. The study lacked a non-exercising control group, was conducted exclusively in young inactive adults, and did not assess long-term adherence or safety outside a supervised setting.
Cited by
- supports Studies by Martin Gibala and others show that performing regular exercise snacks for 6 to 8 weeks improves VO2 max by 2 to 3 mL/kg/min in untrained individuals.