The aim of our study was to compare the cardiovascular and metabolic adjustments of 8 female and 8 male subjects to similar situations of physical stress, which involved muscle contractions at various intensities, and to link the results with the fact that in Scandinavia, women survive men by an average of 5-10 years. The mean age of subjects was 25 years old, and all were in good health. It was concluded that the cardiovascular and metabolic reactions to comparable regimens of physical stress differ markedly between female and male subjects: The women demonstrated the healthier adjustments, with lesser blood pressure elevation and a higher degree of lipid utilization. Both reactions are linked to protective mechanisms with respect to developing ischemic heart disease. We suggest that these adjustments are linked to longevity in women, and that part of the explanation of the sex differences in physiological adjustments to physical stress and in longevity lies in the fact that women through life are subjected to a higher degree of physical activity.