Theme park operators and medical professionals advise children with heart conditions against using rollercoaster rides, but these recommendations are not evidence-based. The underlying assumption is that the combination of adrenergic stimulation through stress and acceleration might trigger arrhythmias in susceptible individuals. We conducted a cross-sectional observational study to assess heart rate and rhythm in healthy children during commercial rollercoaster rides. 20 healthy children (9 male) aged 11–15 (mean 13.3±1.4) years underwent continuous heart rate and rhythm monitoring (2-lead ECG) from 5mins before until 10mins after each of 4 high speed (>50km∙h-1), high G force (Gz>4) commercial rollercoaster rides. Total recording time was 13 h 20 min. No arrhythmic events were detected. Resting heart rate was 81 ± 10 b·min-1 and increased to 158 ± 20 b·min-1 during rides. The highest mean HR (165 ±23 b·min-1) was observed on the ride with the lowest g-force (4.5 g), but one of the highest speeds (100 km∙h-1). Anticipatory tachycardia (126 ±15 b·min-1) within 5 min was frequently observed. A 10 min recovery HR (124 ±17 b·min-1) was 56 % greater than resting HR. The speed and G-force experienced on rollercoasters induce sinus tachycardia but do not elicit pathological arrhythmias in healthy children.