Effects of different intensities of medium-term exercise humid heat acclimation on human blood cells, serum erythropoietin, soluble transferrin receptor, and interleukin 3

Introduction: This study aimed to explore the effects of different intensities of exercise humid heat acclimation on blood cells. Materials and methods: Thirty-two volunteers underwent a nine-day exercise humid heat acclimation (temperature: 28-32celcius, humidity: 85-95%, 30 minutes per day), randomly divided into quiet control group (QC), 55% VO2max (HHA55%), 70% VO2max (HHA70%) and 85% VO2max intensity exercise group (HHA85%). The HHA55%, HHA70%, and HHA85% exercise 30 minutes each day, while the QC sit quietly 30 minutes per day. The day before and after the exercise humid heat acclimation program, we examined the net body weight, sublingual temperature, and venous blood collected from the anterior cubital fossa of participants.Results: We found that hemoglobin (P<0.05), hematocrit (P<0.01), and plateletcrit (P<0.05) were all affected by the intensity of exercise. And compared with pre-exercise, the net body weight in HHA55%, HHA70%, and HHA85% all had varying degrees of decline, but there were no significant; sublingual temperature (P<0.05) and red blood cell count (P<0.05) of HHA70%, hemoglobin (P<0.05) of HHA55%, platelets (P<0.01) and plateletcrit (P<0.01) of QC decreased significantly; hematocrit (P<0.05) of QC, mean corpuscular volume of QC (P<0.01) and HHA55% (P<0.01), and plateletcrit (P<0.05) of HHA85% increased significantly. Compared with pre-exercise, erythropoietin in QC, HHA55% and HHA70% post-exercise increased slightly, and decreased slightly in HHA85%; soluble transferrin receptor in HHA55% increased; interleukin 3 of QC, HHA55%, and HHA70% decreased, but there were all no significant differences compared with pre-exercise and (P>0.05), and nor did between groups.Conclusions: Our results showed that low-and moderate-intensity exercise might positively improve blood cells and anti-inflammatory effects. Low-and moderate-intensity exercise might be a better exercise choice in a humid and hot environment.