Resting Electrocardiogram and Blood Pressure in Young Endurance and Non-Endurance Athletes and Non-Athletes.

Context There is plenty of information on electrocardiogram (ECG) and blood pressure (BP) changes in senior athletes. However, a corresponding data in adolescent athletes are scarce. Objective To study the differences in resting ECG and BP between adolescent endurance athletes, non-endurance athletes, and non-athletes. Design Cross-Sectional Study Setting: A total of 154 youth sports clubs from COUNTRY-XXX and 100 secondary schools for comparison data. Patients or other participants We recruited young athletes (n=410) aged 14-16 among 10 popular sport disciplines, including both winter and summer as well as team and individual sports, and categorized them as "endurance sports" or "non-endurance sports". Comparison data composed of age-matched non-sports club participants (n=164) collected via secondary schools. Main outcome measure(s) Resting ECG including heart rate, PR interval, QRS duration, QRS axis, QRS amplitude, T axis and QT interval as well as systolic and diastolic blood pressure from all participants. Results No differences in any ECG variable of interest was found between the endurance and non-endurance athletes. The PR interval was longer in endurance athletes than in non-athletes (P = .05). The QRS amplitude (P = .03) was higher among non-endurance athletes than in non-athletes. Diastolic BP among endurance (P = .002) and non-endurance (P = .02) athletes was lower than non-athletes. Endurance athletes (OR 2.85, 95% CI 1.81-4.50) and non-endurance athletes (OR 2.19, 95% CI 1.43-3.35) were more likely to have sinus bradycardia than non-athletes. Non-endurance athletes were more likely to have elevated systolic BP than endurance athletes (OR 1.70, 95% CI 1.07-2.72) and non-athletes (OR 1.73, 95% CI 1.04-2.87). Conclusions Young athletes mainly have similar ECG and BP findings independent of the sport. Particular physiological adaptations like sinus bradycardia, higher QRS amplitude and lower diastolic BP, commonly found in adult athletes, are visible also among adolescent athletes.