Enhancement of finger blood flow response of postprandial human subjects to the increase in body temperature during exercise

Summary The present study was performed to investigate the effect of food intake on thermoregulatory vasodilatation in seven healthy male volunteers. The changes in oesophageal (T _oes) and mean skin temperatures, finger and forearm blood flows (BF), oxygen consumption (VO₂) and heart rate (f _c) with and without food intake were measured before and during a 40-min exercise at an intensity of 35% maximal O₂ consumption at an ambient temperature of 25°C. Exercise commenced 60 min after food intake. Ingestion of food equivalent to 50.2 kJ · kg body mass^–1 elevated mean body temperature, BF,VO₂ andf _c in 60 min. Four subjects responded to exercise with a marked increase in finger BF and with no sweating (non-sweating group), while the other three responded with perspiration over almost the whole skin area and with little change in finger BF. Further analyses were made mainly in the non-sweating group. The postprandial increases inT _oes, BF,VO₂ andf _c were persistent during exercise. The rate of increase in finger BF with the increase inT _oes and mean body temperature was significantly greater with food intake than without. However, there was no difference in the response of forearm BF to exercise between the two conditions. These results suggested that food intake enhanced finger BF response to the increase in deep body temperature during exercise. It was also concluded that there was a regional difference in cutaneous vasomotor response to thermal load in the post-prandial subjects.