Children in sauna: electrocardiographic abnormalities.

We studied changes in ECG in 81 children and 20 adolescents and young adults when they were exposed to heat stress in a climatic chamber, which resembled an ordinary Finnish sauna. Changes were similar to those caused by increased sympathetic activity in 57% of the subjects during the bath and in 23% during the recovery period. Three children had extrasystoles during and four after sauna. One previously healthy 5-year-old girl with wandering pacemaker suffered a 3.3 sec sinus arrest and had reversible junctional rhythm during the heat exposure. We conclude that, although these changes were transient and benign, the sinus arrest suggest that heat stress in sauna is considerable and may be risky for those children who have disorders of the sinoatrial node.