Mixed
Low-volume sprint interval training (SIT) and high-intensity interval training (HIIT) elicit similar physiological and health-related adaptations (e.g., VO2max, mitochondrial content) to high-volume moderate-intensity continuous training (MICT) despite significantly lower time commitment and total work volume.
You do not need to spend hours exercising to improve your heart health and fitness. Short bursts of intense effort (like 30-second sprints or 1-minute high-intensity intervals) repeated a few times, with rest in between, can improve your cardiovascular fitness and muscle efficiency just as much as long, steady-state cardio, but in a fraction of the time.
Short-term SIT and HIIT protocols have also been shown to improve health-related indices... elicit physiological remodeling that resembles changes normally associated with high-volume MICT.
Why this rating
Based on a review of multiple studies including direct comparisons and meta-analyses, though some individual studies have small sample sizes.
Source
Physiological and Health-Related Adaptations to Low-Volume Interval Training: Influences of Nutrition and Sex
Martin J. Gibala et al. · Sports Medicine · 2014
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →