CARDIOVASCULAR EFFECTS OF ATENOLOL, SCOPOLAMINE AND THEIR COMBINATIONON HEALTHY-MEN IN FINNISH SAUNA BATHS

Indicators of cardiovascular strain were studied in 12 healthy young m en under the influence of drugs affecting the autonomic nervous system during the course of taking a sauna bath. There were four bath sessio ns: one without a drug (control) and three with drug pretreatment (Ate nolol 50 mg or Scopolamine 0.3 mg or their combination taken orally 2 h before the bath). The time spent in the hot room depended on the sub jective rating of heat stress. Its mean duration at a temperature of 8 8 degrees C (dry bulb) was 22 (range 14-33) min and did not differ sig nificantly among the sessions. In the Atenolol experiment the mean res ting heart rate before the bath was significantly lower (P < 0.001, AN OVA of repeated measures) than in the other experiments. The increase in heart rate per minute of heat exposure was significantly lower (P < 0.001) in the Atenolol experiment and higher (P = 0.017) in the Scopo lamine experiment than in the other experiments. The systolic blood pr essure increased more slowly (P = 0.004) and the diastolic pressure de creased less (P = 0.02) in the Atenolol experiment than in the other e xperiments. Heart rate and blood pressure returned to their initial le vels during the 30-min recovery after the heat exposure. The plasma no radrenaline concentrations increased approximately twofold during all of the bath sessions, whereas the plasma adrenaline and serum thrombox ane B-2 concentrations showed no consistent alterations. A small oral dose of Scopolamine alone or in combination with Atenolol produced no marked cardiovascular strain in healthy men during a sauna bath.