PURPOSE: To observe the effects of exercise in different environmental conditions on leukocyte counts and subsets. METHODS: Recreationally active Caucasian males (n=7; 23.9±2.4 yrs; 182.9±5.6 cm; 83.4±8.0 kg; 12.8±3.6 %BF; 47.3±5.9 ml·kg-1·min-1) completed an aerobic exercise protocol in low temperature (LT; 5°C), moderate temperature (MT; 22°C), and high temperature (HT; 35°C). The exercise protocol consisted of a 60-minute cycling trial at 60% VO2max, a 15-minute rest period, and a time to exhaustion trial at 90% VO2max (TTE). Blood draws were completed before (PRE) and after (60P) the 60-minute trial; immediately after TTE (90P), and one hour post-TTE (REC). 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. Changes were analyzed using a time × trial within-subjects repeated measures ANOVA. RESULTS: For all trials, WBC increased at all time points relative to PRE (p’sp=0.015) and was elevated from PRE–90P in all trials (p’s=0.002-0.011). A time effect was observed for MO# (p=0.026) and GR# (ppp=0.001), and GR% (p<0.001). LY% decreased at REC (p>0.001); MO% decreased at all timepoints (p’sp’sConclusion: Temperature may not affect acute exercise-induced increases in total leukocyte counts. However, exercise in the heat (35°C) induces a greater increase in circulating lymphocyte counts when compared to exercise in moderate (22°C) and cold (5°C) temperatures.
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.
Exercise Post-Oxygen Consumption in Response to Cycling at Various Intensities.
Lauren D. Watson, Cody S. Dulaney, Tricia L. Hart, Eliott Arroyo, Adam R. Jajtner
Exercise Physiology Program, Kent State University, Kent, OH
Purpose: The purpose of this investigation is to assess exercise post oxygen consumption (EPOC) in response to high-intensity interval training versus moderate continuous training cycling. Methods: Two recreationally active men (21.3 ± 3.51 yrs; 182.83 ± 6.25 cm; 79.36 ± 8.69 kg; 3.57 ± 0.10 L∙min-1) completed three trials: a graded exercise test, and two cycling trials in a randomized order: a high-intensity interval (HII) and moderate continuous (MC) bout. Baseline VO2 was assessed for 30 minutes prior to each cycling trial. During HII, participants completed 15 90-second bouts of exercise at 85% VO2max with 90-second active recovery periods at 25% VO2max. During MC participants cycled for 45-minutes at 65% VO2max. For both conditions, participants completed a 5-minute warm-up and 3-minute cool down at 25% VO2max. Recovery VO2 was assessed within 3 minutes of completing the cool down for 60 minutes. Respiratory gasses were analyzed every 5 minutes during recovery. Results: Preliminary data shows an average oxygen consumption of 3.87 ± 0.83 mL/kg/min for HII and 3.91 ± 0.52 mL/kg/min for MCT. Also, the average oxygen consumption at the beginning of rest was 5.32 ± 0.48 ml/kg/min and declined to 3.93 ± 0.31 mL/kg/min at the end of recovery. Conclusion: Average and decline in VO2 response was similar during 60 minutes of quiet rest in the HII compared to the MC despite differences in exercise intensity during each protocol.