Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training despite a Five-Fold Lower Exercise Volume and Time Commitment.
We investigated whether sprint interval training (SIT) was a time-efficient exercise strategy to improve insulin sensitivity and other indices of cardiometabolic health to the same extent as traditional moderate-intensity continuous training (MICT). SIT involved 1 minute of intense exercise within a 10-minute time commitment, whereas MICT involved 50 minutes of continuous exercise per session.



Sedentary men (27±8y; BMI = 26±6kg/m2) performed three weekly sessions of SIT (n = 9) or MICT (n = 10) for 12 weeks or served as non-training controls (n = 6). SIT involved 3x20-second 'all-out' cycle sprints (~500W) interspersed with 2 minutes of cycling at 50W, whereas MICT involved 45 minutes of continuous cycling at ~70% maximal heart rate (~110W). Both protocols involved a 2-minute warm-up and 3-minute cool-down at 50W.



Peak oxygen uptake increased after training by 19% in both groups (SIT: 32±7 to 38±8; MICT: 34±6 to 40±8ml/kg/min; p<0.001 for both). Insulin sensitivity index (CSI), determined by intravenous glucose tolerance tests performed before and 72 hours after training, increased similarly after SIT (4.9±2.5 to 7.5±4.7, p = 0.002) and MICT (5.0±3.3 to 6.7±5.0 x 10-4 min-1 [μU/mL]-1, p = 0.013) (p<0.05). Skeletal muscle mitochondrial content also increased similarly after SIT and MICT, as primarily reflected by the maximal activity of citrate synthase (CS; P<0.001). The corresponding changes in the control group were small for VO2peak (p = 0.99), CSI (p = 0.63) and CS (p = 0.97).



Twelve weeks of brief intense interval exercise improved indices of cardiometabolic health to the same extent as traditional endurance training in sedentary men, despite a five-fold lower exercise volume and time commitment.
Department of Kinesiology, McMaster University, Hamilton, ON, Canada.
Jenna B
0000-0003-4709-756X
JB
Gillen
Department of Kinesiology, McMaster University, Hamilton, ON, Canada.
Brian J
BJ
Martin
Department of Kinesiology, McMaster University, Hamilton, ON, Canada.
Martin J
MJ
MacInnis
Department of Kinesiology, McMaster University, Hamilton, ON, Canada.
Lauren E
LE
Skelly
Department of Kinesiology, McMaster University, Hamilton, ON, Canada.|Department of Pediatrics and Medicine, McMaster University, Hamilton, ON, Canada.
Mark A
MA
Tarnopolsky
Department of Kinesiology, McMaster University, Hamilton, ON, Canada.
Martin J
MJ
Gibala
D000293:Adolescent; D000328:Adult; D004734:Energy Metabolism; D015444:Exercise; D005951:Glucose Tolerance Test; D000072696:High-Intensity Interval Training; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D010101:Oxygen Consumption; D010807:Physical Endurance; D055815:Young Adult