The results of this are that during exercise stroke volume, pH, pCO2, and pO2 of arterial blood remain nearly the same. Minute volume may increase by about 5X maximum. At this level however, stroke volume would have to increase. Limits to exercise levels are the ability to pump blood, not the ability to take in O2. Cardiovascular Responses to Diving Diving mammals and birds have a reflex apnea caused by sensors in the nose and pharynx.
Animals relax all but swimming muscles.
Lower metabolic rate. The sympathetic system nearly shuts down peripheral blood flow so that blood circulates mostly via heart, lung, and brain only. Diving animals normally have high blood volumes, high myoglobin levels, high hematocrit and hemoglobin levels. Explain Starlings Law of the Heart. Anemia drastic blood loss.