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Hemodynamics in young athletes following high-intensity interval or moderate-intensity continuous training.

BACKGROUND
The present study aimed to investigate the effects of HIIT versus moderate-intensity continuous training (MICT) on blood pressure (BP) and parameters of arterial stiffness in young athletes.


METHODS
17 rowers (aged 16±1.4 years) were randomized into an intervention group (IG) (n=10) and the control group (CG) (n=7). During an 8-week intervention period, the IG completed a HIIT on the rowing ergometer twice weekly (2x4x2 min at ≈95% of maximum heart rate (HRmax), 60-sec rest) in addition to the regular rowing training (3x/week MICT 70-90min, ≈70% HRmax). The CG completed the regular normal rowing training and, instead of the HIIT units, two additional MICT units (70-90min, ≈70% HRmax). Before and after the intervention period, hemodynamic parameters were recorded non-invasively in both groups.


RESULTS
After the intervention period, there was a significant decrease in peripheral systolic (p = 0.01) and diastolic (p =0.05) BP, as well as in central systolic (p = 0.05) and diastolic BP (p = 0.03) in the IG. Furthermore, pulse wave velocity (p = 0.05) was significantly reduced. Analysis of intervention effects revealed significant between-group differences in central diastolic BP (p = 0.05), in augmentation pressure (p = 0.02), and in augmentation index (p = 0.006) favoring IG. The CG showed no significant changes in the respected parameters throughout the intervention.


CONCLUSIONS
Already in adolescent athletes, a HIIT intervention has beneficial effects on peripheral and central BP as well as on pulse wave velocity, augmentation pressure, and augmentation index.