Specific characteristics of neurohumoral stimuli in cardiorespiratory responses and energy supply during rowers' performance

Abstract

This study evaluated the physiological conditions under which load-induced hypoxia, hypercapnia, and lactate acidosis elicit responses in the rowers' cardiorespiratory system (CRS). Materials and methods: Forty elite male rowers (age 25.5 ± 2.3 years, weight 95.5 ± 3.7 kg, height 191.7 ± 2.8 cm) participated in the study. The role of neurohumoral stimuli ("drives") was investigated by simulating the transitional processes of hypoxia– hypercapnia–lactate acidosis a cross different phases of a simulated 2000-m race。Results. An analysis was conducted on athletes with high (group A) and low (group B) levels of specialized work capacity. The mean ± SD values for specific work capacity were 438.5 ± 7.6 for group A and 405.3 ± 10.8 for group B (significant difference: t = 4.248529, p = 0.000022). Aerobic capacity (VO2 max) was 5.62 ± 0.18 for group A and 5.09 ± 0.19 for group B (t = 3.919930, p = 0.000089), and anaerobic capacity (La max) was 18.51 ± 0.93 for group A and 16.60 ± 0.81 for group B (t = 4.014509, p = 0.000060). The “drives” data — the stimulus–response characteristics — comprised the following metrics for Groups A and B: EQPaCO2 test 10 s: A = 2.02 ± 0.13; B = 1.74 ± 0.11; t = 4.014509, p = 0.000060. EQPaCO2 test 30 s: A = 3.81 ± 0.11; B = 3.63 ± 0.10; t = 3.875478, p = 0.000106.VCO2 test 30 s: A = 3.89 ± 0.25; B = 3.73 ± 0.20; t = 2.343236, p = 0.019118. EQCO2 ST (step test): A = 34.54 ± 1.39; B = 35.70 ± 1.24; t = 2.937021, p = 0.003314. VCO2 ST: A = 5.69 ± 0.14; B = 5.19 ± 0.18; t = 3.919930, p = 0.000089. La at VO2 max: A = 14.50 ± 0.64; B = 13.35 ± 0.93; t = 3.079945, p = 0.002071. EqCO2 CrP: A = 36.53 ± 0.79; B = 35.72 ± 1.08; t = 3.510523, p = 0.000060. La test 30 s / La CrP (%): A = 60.05 ± 1.04; B = 52.55 ± 2.15; t = 4.014509, p = 0.000060. EqO2 ST / EqO2 CrP (%): A = 4.63 ± 1.99; B = 5.20 ± 2.65; (not significant: t = 0.677774, p = 0.497915). EqCO2 ST / EqCO2 CrP (%): A = 6.48 ± 1.63; B = 3.69 ± 2.20; t = 3.215083, p = 0.001304. Conclusion.An adequate and complete response to workloadinduced hypoxia, hypercapnia, and lactate acidosis was manifested by enhanced rapid kinetics of the CRS (EqPaCO2 test 10 s and 30 s, VCO2 test 30 s), prolongation of the steady state (VCO2 ST, EqVCO2 ST, La at VO2 max), and mobilization of functions during fatigue compensation (La test 30 s / La CrP, EqO2 ST / EqO2 CrP, EqCO2 ST / EqCO2 CrP). Taken together, these responses form the structure of the reactive properties of the rowers’ CRS.