Heart rate monitoring is common in endurance sports, and has established itself as a tool for training management. The present study addressed potential differences in the development of initial endurance capacity in normoxia and normobaric hypoxia (NH), using heart rate controlled running exercises (TE) as part of a 4-week endurance training. We tested the functional regulation of the autonomic nervous system on the respiratory control. For the study, 24 endurance athletes (20-35 years) were tested. They performed a test including repeated inhalation of pure nitrogen for 3-8 breaths to determine the hypoxic ventilatory response. A treadmill test was performed to determine the endurance capacity. Oxygen uptake and heart rate were recorded continuously and lactate was determined after every step. Subsequently, subjects were randomized divided into an experimental group (VG: FiO2 15.0 %, N = 12) or control group (KG: normoxia, FiO2 20.9 %, N = 12). The pre-test was followed by a 4-week training intervention with 20 treadmill exercises under laboratory conditions with 60min duration. The VG trained in an altitude chamber. After the intervention the test protocol of the pre-test was repeated in the post-test. The data was statistically analyzed using SPSS. VG and KG did not differ in terms of endurance capacity at the pre-test (vmax: VG 16.33 ± 1.39 km/h, KG 16.26 ± 1.48 km/h; V02peak: VG 52.77 ± 5.39 ml*(min * kg)-1, KG 52.26 + 5.82 ml*(min * kg)-1. The initial values for the peripheral chemosensitivity were nearly identical for VG and KG (VG: 0.33 ± 0.07 l*(min* %)-1, KG: 0.34 ± 0.09 l*(min* %)-1. The comparison of pre-and post-treadmill test in both groups revealed a significant increase in VO²peak and the speed at the 2 - and 4 mmol /l lactate threshold (p < 0.05). An interaction effect could not be detected. In the post-test, a significant increase was found in the chemoreceptor sensitivity in the VG (0.48 ± 0.16 *(min * %)-1. p = 0.008) but not in the KG (0.32 ± 0.15 l*(min* %)-1, p = 0.706). In the VG, the amount of total kilometers during the completed training was significantly lower (p - 0.003) We concluded that a heart rate controlled training intervention under normobaric hypoxia has comparable effects on endurance capacity to training in normoxic conditions.
© Copyright 2011 Herzfrequenzvariabilität: Gesundheitsförderung - Trainingssteuerung - Biofeedback. Internationales Symposium am 29. und 30. Oktober.. Veröffentlicht von Feldhaus, Ed. Czwalina. Alle Rechte vorbehalten.