Three minutes of all-out intermittent exercise per week increases skeletal muscle oxidative capacity and improves cardiometabolic health

PLoS One. 2014 Nov 3;9(11):e111489. doi: 10.1371/journal.pone.0111489. eCollection 2014.

Abstract

We investigated whether a training protocol that involved 3 min of intense intermittent exercise per week--within a total training time commitment of 30 min including warm up and cool down--could increase skeletal muscle oxidative capacity and markers of health status. Overweight/obese but otherwise healthy men and women (n = 7 each; age = 29±9 y; BMI = 29.8±2.7 kg/m2) performed 18 training sessions over 6 wk on a cycle ergometer. Each session began with a 2 min warm-up at 50 W, followed by 3×20 s "all-out" sprints against 5.0% body mass (mean power output: ∼450-500 W) interspersed with 2 min of recovery at 50 W, followed by a 3 min cool-down at 50 W. Peak oxygen uptake increased by 12% after training (32.6±4.5 vs. 29.1±4.2 ml/kg/min) and resting mean arterial pressure decreased by 7% (78±10 vs. 83±10 mmHg), with no difference between groups (both p<0.01, main effects for time). Skeletal muscle biopsy samples obtained before and 72 h after training revealed increased maximal activity of citrate synthase and protein content of cytochrome oxidase 4 (p<0.01, main effect), while the maximal activity of β-hydroxy acyl CoA dehydrogenase increased in men only (p<0.05). Continuous glucose monitoring measured under standard dietary conditions before and 48-72 h following training revealed lower 24 h average blood glucose concentration in men following training (5.4±0.6 vs. 5.9±0.5 mmol/L, p<0.05), but not women (5.5±0.4 vs. 5.5±0.6 mmol/L). This was associated with a greater increase in GLUT4 protein content in men compared to women (138% vs. 23%, p<0.05). Short-term interval training using a 10 min protocol that involved only 1 min of hard exercise, 3x/wk, stimulated physiological changes linked to improved health in overweight adults. Despite the small sample size, potential sex-specific adaptations were apparent that warrant further investigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Adult
  • Blood Glucose
  • Energy Metabolism
  • Exercise*
  • Female
  • Health Status Indicators
  • Humans
  • Male
  • Mitochondria / metabolism
  • Muscle, Skeletal / metabolism*
  • Myocardium / metabolism*
  • Obesity / blood
  • Obesity / metabolism
  • Overweight / blood
  • Overweight / metabolism
  • Oxygen Consumption*
  • Time Factors
  • Young Adult

Substances

  • Blood Glucose

Grant support

This project was supported by a Natural Sciences and Engineering Research Council (NSERC) operating grant and McMaster University Internally Sponsored Research Grant to MJG. JBG held a NSERC Vanier Canada Graduate Scholarship. MEP was supported by a NSERC Canada Graduate Scholarship (Masters). LES held a NSERC undergraduate student research award and NSERC Canada Graduate Scholarship (Masters). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.