[Acute myocardial infarction and cerebral infarction at Kusatsu-spa].

From January 1989 to June 1995, 31 patients were admitted to our hospital with acute myocardial infarction (15 were tourists and 16 were Kusatsu residents) and 40 were admitted with cerebral infarction (15 tourists and 25 Kusatsu residents). We examined the possibility that hot hot-spring bathing was related to the occurrence of their illness. Fifteen patients with acute myocardial infarction (9 tourists and 6 Kusatsu residents) and 27 patients with cerebral infarction (11 tourists and 16 Kusatsu residents) had a hot hot-spring bath within 24 hours before the onset of symptoms. In 12 of the 15 with acute myocardial infarction (6 tourists and 6 Kusatsu residents) and in 15 of the 27 with cerebral infarction (9 tourists and 6 Kusatsu residents), symptoms began within 3 hours after they began bathing. In 2 of the remaining 3 patients with acute myocardial infarction and in 8 of the remaining 12 patients with cerebral infarction, bathing at night was followed by the onset of symptoms the next morning (more than 3 hour later). Acute myocardial infarction and cerebral infarction within 3 hours after hot hot-spring bathing may be attributable to transient change in blood pressure, heart rate, blood viscosity, fibrinolytic activity, and platelet function. We described previously that hot hot-spring bathing at night can accentuate the nocturnal decrease in blood pressure and can make the early morning increase in blood viscosity more abrupt. These phenomena may account for the occurrence of acute myocardial infarction and cerebral infarction early in the morning.