Leukocytes and lactate responses to cycling and running at the same target heart rate.

Heart Rate (HR) is widely used for erobic exercise intensity prescriptions and/or studies of exercise training. It is often assumed that exercising at a given HR results in similar physiological response, regardless of exercise modality. This study aimed to gauge cellular immune mobilization to submaximal exercise at a given target HR on a cycle ergometer (CE) and treadmill (TM). Thirteen healthy male adults (23.2 ± 3.5 y.o) completed 4 laboratory visits. Participants performed two graded exercise tests to exhaustion on CE and TM and two 30‐min constant exercise challenges at 70% HR reserve on CE or TM in random order. Rating of Perceived Exertion (RPE) was recorded every 5 min, and blood was drawn before and after exercise to measure leukocytes subpopulation levels, lactate, and IL‐6. HR was successfully "clamped" during the exercise in CE and TM (CE 156.7 ± 1.1; TM 159.3 ± 1.6 bpm). Cycling was perceived as more strenuous than running and was accompanied by a greater increase in lactate post‐exercise (p < 0.0001; 6.2 ± 0.3 vs. 2.9 ± 0.3 mmol/L). IL‐6 and leukocytes subpopulations were significantly elevated post‐exercise (p < 0.003) with no difference between exercise modalities (monocytes; CE 57.6% TM 61.2%, granulocytes; CE 41.37%, TM 50.1%, lymphocytes; CE 91.03%, TM 78.8%). The findings revealed that HR is not sufficient in and of itself to fully assess the metabolic stress associated with a given exercise modality. However, despite different metabolic and subjective stress, the IL‐6 and leukocyte counts relative changes were similar in the two modalities. Highlights: These findings provide valuable insights into the leukocytes and lactate responses to cycling and running at the same target heart rate. The study further elaborates on the shared patterns and distinctions in physiological and metabolic responses and their implications for designing targeted training programs.At the same target heart rate, running resulted in significantly lower lactate levels and subjective rate of perceived exertion (RPE) while yielding higher VO2 levels compared to cycling.Leukocytes and IL‐6 increases post‐exercise were not different between running and cycling, indicating that they did not reflect the distinct metabolic and subjective perceived loads associated with cycling and running.Since heart rate in and of itself is not sufficient to fully characterize the metabolic stress induced by a specific exercise modality, it is important to consider the modality of exercise when prescribing training programs for improving cardiovascular fitness or achieving target energy expenditure through heart rate monitoring. [ABSTRACT FROM AUTHOR]