Gender differences in cardiovascular and catecholamine responses to cold-air exposure at rest

Metabolic and cardiovascular responses were examined in 8 men and 9 women during 2 hrs of sitting at rest in 5 degrees C. The men and women had similar body fatness and both groups responded with similar changes relative to control in cardiac output, blood pressure, total peripheral resistance, VO2, respiratory exchange ratio, and rectal temperature. However, greater increases in stroke volume and decreases in heart rate and skin temperature were observed in men compared to women (p < 0.05). The contribution of CHO and fat to the total energy expended differed (p < 0.05) between genders; the CHO:fat ratio was 47:53 in men and 36:64 in women. No gender differences could be observed in plasma catecholamines. It is concluded that there are striking cardiovascular and metabolic gender differences in response to cold stress which cannot be accounted for by body fatness or catecholamine responses.