Elevation of arterial blood pressure in the squirrel monkey at 10 degrees C

Systemic arterial blood pressure, heart rate, and total body oxygen consumption were measured in seven unanesthetized squirrel monkeys exposed to ambient temperatures of 28 degrees C and 10 degrees C. At 28 degrees C, subjects sat quietly, the average mean arterial blood pressure was 116 +/- 16 (mean +/- SD, n - 7) mmHg, heart rate was 274 +/- 31 beats/min, and oxygen consumption was 14 +/- 1.4 ml/kg-min. At 10 degrees C, the animals shivered vigorously, the average mean arterial blood pressure was 139 +/- 16 mmHg, heart rate was 328 +/- 18 beats/min, and oxygen consumption was 31.6 +/- 3.9 ml/kg-min. Thus, the oxygen consumption more than doubled, the blood pressure rose by approximately 21%, and the heart rate by approximately 20%. Elevations in heart rate as well as systemic mean arterial blood pressure during exposure to low ambient temperature were probably mediated by sympathetic-adrenal discharges as well as by activity of skeletal muscles.