High-intensity interval training (HIIT) represents an effective method to improve
cardiometabolic health in adolescents. This study aimed to investigate the effect
of 4 weeks of HIIT followed by 2 weeks of detraining on vascular function and
traditional cardiovascular disease (CVD) risk factors in adolescent boys. Nineteen ...
High-intensity interval training (HIIT) represents an effective method to improve
cardiometabolic health in adolescents. This study aimed to investigate the effect
of 4 weeks of HIIT followed by 2 weeks of detraining on vascular function and
traditional cardiovascular disease (CVD) risk factors in adolescent boys. Nineteen male
adolescents (13.3 ± 0.5 years) were randomly allocated to either a training (TRAIN,
n = 10) or control (CON, n = 9) group. Participants in TRAIN completed 4 weeks of
HIIT running with three sessions per week. Macro- (flow-mediated dilatation, FMD)
and microvascular (peak reactive hyperaemia, PRH) function, body composition (fat
mass, fat free mass, body fat percentage) and blood biomarkers (glucose, insulin, total
cholesterol, high- and low-density lipoprotein, triacylglycerol) were assessed pre-,
48 h post- and 2 weeks post-training for TRAIN and at equivalent time points for
CON. Following training, FMD was significantly greater in TRAIN compared to CON
(9.88 ± 2.40% and 8.64 ± 2.70%, respectively; P = 0.036) but this difference was
lost 2 weeks after training cessation (8.22 ± 2.47% and 8.61 ± 1.99%, respectively;
P = 0.062). No differences were detected between groups for PRH (P = 0.821),
body composition (all P > 0.14) or blood biomarkers (all P > 0.18). In conclusion,
4 weeks of HIIT improved macrovascular function; however, this training period did
not measurably change microvascular function, body composition or blood biomarkers.
The reversal of the FMD improvement 2 weeks post-training highlights the importance
of the continuation of regular exercise for the primary prevention of CVD.