Effects of age-related blood pressure response during exercise: focus on splanchnic blood flow

Abstract

During dynamic exercise, blood flow to active muscles increases, while blood flow to inactive organs, such as inactive limbs and splanchnic organs, decreases. At resting conditions, the splanchnic region and renal receive about 50% of cardiac output, while this is reduced to 20-25% of basal values during maximal dynamic exercise. Differences in splanchnic blood flow during exercise have been observed between younger and older males. However, to our knowledge, no data exist on age-related differences in splanchnic blood flow during dynamic exercise in females. This study aimed to elucidate the effects of aging in females on arterial blood pressure and celiac artery blood flow responses during light-intensity dynamic exercise. Ten young females （YF; 20±2 yrs, mean±SD） and ten elderly females （EF; 71±5 yrs） performed dynamic knee-extension and -flexion for 4-min at 30% heart rate reserve. Heart rate （HR） , mean arterial blood pressure （MAP; automated sphygmomanometer） , and celiac artery mean blood flow （celMBF; Doppler ultrasound） were measured continuously during the experiment. HR increased in both groups at the onset of exercise and was maintained throughout the exercise. The increase in HR was larger in the YF than in EF as expected （+37.3±5.5 vs. +26.0±5.3 beats/min, P<0.001）．The rise in MAP during exercise was greater in the EF than in YF （+27.2±10.3 vs. +12.8±6.9 mmHg, P<0.001）．celMBF decreased during exercise in both groups, with no significant difference between YF and EF （-100.3±64.5 vs. -84.7±68.9 mL/min, P=0.61）．Similarly, vascular conductance （celVC; celMBF/MAP） decreased during exercise in both groups, with no significant difference in response between YF and EF （-1.8±1.0 vs. -1.5±0.7 mL/min/mmHg, P=0.33）．These results suggest that aging has minimal impact on changes in celiac artery blood flow during light-intensity dynamic exercise in females.