Hematological Responses to High-Intensity Interval Training, Sprint Interval Training, and Moderate-Intensity Continuous Training04/09/2019
PURPOSE: To compare the effects of high-intensity interval training (HIIT), sprint interval training (SIT), and moderate-intensity continuous training (MCT) on leukocyte counts and subsets. METHODS: Recreationally active men (n=2; 22±2 yrs) completed a maximal graded exercise test (VO2max) and three exercise trials (HIIT, SIT, and MCT) in a randomized, counterbalanced fashion on a cycle ergometer. HIIT consisted of fifteen 90-second bouts at 85% VO2max interspersed with 90-second active recovery periods. SIT consisted of fifteen 20-second bouts at 130% maximum wattage interspersed with 160-second active recovery periods. MCT was a single continuous bout at 65% VO2max. Each trial lasted 53 minutes, including a 5-minute warm-up and a 3-minute cool-down. Blood was collected before (PRE), immediately post (IP), 30 minutes (30M), 2 hours (2H), 6 hours (6H) and 24 hours (24H) post-exercise. Leukocyte count (WBC), lymphocyte number and ratio (LY# and LY %), monocyte number and ratio (MO# and MO%) and granulocyte number and ratio (GR# and GR%) were analyzed via hematology analyzer. RESULTS: MCT elicited the largest decrease in WBC at 30M compared to the other trials while HIIT led to the largest increase in WBC at IP relative to PRE compared to the other trials. HIIT also elicited the largest decrease in LY# at 2H compared to the other trials. Also, SIT led to a slight decrease in LY# at IP while the other conditions elicited an increase in this subset. CONCLUSION: Preliminary data suggests that MCT may lead to the largest suppression in WBC comparted to HIIT and SIT.