Influence of age, weight and height on oxygen pulse during maximal exercise

Oxygen pulse (O2 pulse) is an important index of cardiovascular efficiency. Low O2 pulse may reflect deconditioning, cardiovascular disease, or exercise limitation. The present study measured the influence of age, weight and height on O2 pulse in 140 Thai adults aged 20 to 78 years old (51 males, 89 females). All subjects underwent cardiopulmonary exercise testing using a treadmill ramp protocol to the symptom-limited maximum. O2 pulse, cardiac output (CO), and stroke volume (SV) at maximal exercise in males were higher than in females by 60%, 70% and 60%, respectively (p<0.001). Linear regression analyses revealed a negative correlation between O2 pulse and age (r= -0.334, p<0.001), and positive correlations between O2 pulse and weight (r= 0.582, p<0.001) and O2 pulse and height (r= 0.616, p<0.001). The lower O2 pulse in women may be explained by gender-related differences in maximal HR, SV, CO, peripheral oxygen extraction, or heart size. The decline in O2 pulse with age may be due to reduction in lean body mass and skeletal muscle blood flow, while increased O2 pulse with weight and height is probably due to increasing amount of oxygen consumed. We conclude that the O2 pulse varies with age, genders, weight, and height in healthy adults.