A Comparison of the Gluco-Regulatory Responses to High-Intensity Interval Exercise and Resistance Exercise.
Level 2 - randomized trial
Individual randomized crossover trial
PubMed 33401694 · doi:10.3390/ijerph18010287
What was done
Sixteen recreationally active adults (8 males, 8 females; mean age 22 ± 7 years) participated in a randomized crossover study with a 7-day washout period between trials. In an overnight-fasted state, participants completed either high-intensity interval exercise (twelve 30-second cycling intervals at 80% peak power with 90-second active recovery) or duration-matched resistance exercise (4 sets of 10 repetitions across 3 lower-limb exercises at 80% 1-RM). Blood samples were collected every 30 minutes for 2 hours post-exercise to evaluate gluco-regulatory and cortisol responses.
What was found
There was a statistically significant time-by-intervention interaction for blood glucose (p = 0.02), with post-exercise glucose averaging 0.7 ± 0.7 mmol/L higher after interval cycling than after resistance exercise. Cortisol concentration over time was also significantly different between interventions (p = 0.03), averaging 70 ± 103 ng/mL higher following interval exercise compared to resistance exercise (p = 0.015).
Why it matters
These findings indicate that acute high-intensity interval exercise induces a transient spike in glucose and cortisol that does not occur with heavy resistance exercise. This helps clarify how exercise modality influences acute gluco-regulatory mechanisms in fasting conditions.
Limits
The sample size was small (n = 16) and restricted to young, healthy, recreationally active adults, limiting generalizability to populations with impaired glucose tolerance or diabetes. The study measured only acute responses up to 2 hours post-exercise in a fasted state, without assessing long-term glycemic control, insulin levels, or postprandial responses.
Cited by
- context High-intensity resistance training causes acute transient spikes in both circulating glucose and cortisol as part of sympathetic nervous system activation.