There is evidence that an integrated cardiorespiratory and muscular response to exercise may be modulated by childhood patterns of physical activity and exercise. The time to respond to the onset of exercise and to recover is faster in children than in adults. These responses are also faster in lean children than those who are obese. This suggests that CO 2 transport from cells to the lungs is delayed by the high solubility of CO 2 in adipose tissue. This may also explain the differences in CO 2 transport dynamics between adults and children since adiposity increases with age in adults.
Children also work less efficiently in terms of oxygen cost of exercise than do adults.
Patterns of physical activity during childhood may affect the incidence and morbidity of disease later in life. Peripheral mechanisms of exercise stimulation . Energy generated by exercise is transformed into signals that stimulate cellular anabolism at the site of the exercise. Physical stretch profoundly influences endothelial cell orientation and actin cytoskeleton organization. In exercising muscle, PO 2 and pH are low and lactate concentrations are high.