Hypoxic ventilatory response is correlated with increased submaximal exercise ventilation after live high, train low

Abstract

This study tested the hypothesis that live high, train low (LHTL) would increase submaximal exercise ventilation (V(E)) in normoxia, and the increase would be related to enhanced hypoxic ventilatory response (HVR). Thirty-three cyclists/triathletes were divided into three groups: 20 consecutive nights of hypoxia (LHTLc, n = 12), 20 nights of intermittent hypoxia (4x5-night 'blocks' of hypoxia interspersed by two nights of normoxia, LHTLi, n = 10), or control (CON, n = 11). LHTLc and LHTLi slept 8-10 h per night in normobaric hypoxia (2,650 m), and CON slept under ambient conditions (600 m). Resting, isocapnic HVR (DeltaV(E)/Deltablood oxygen saturation) was measured in normoxia before (PRE) and after 15 nights (N15) hypoxia. Submaximal cycle ergometry was conducted PRE and after 4, 10, and 19 nights of hypoxia (N4, N10, and N19 respectively). Mean submaximal exercise V(E) was increased (P < 0.05) from PRE to N4 in LHTLc [74.4 (5.1) vs 80.0 (8.4) l min(-1); mean (SD)] and in LHTLi [69.0 (7.5) vs 76.9 (7.3) l min(-1)] and remained elevated in both groups thereafter, with no changes observed in CON at any time. Prior to LHTL, submaximal V(E) was not correlated with HVR, but this relationship was significant at N4 (r = 0.49, P = 0.03) and N19 (r = 0.77, P < 0.0001). Additionally, the increases in submaximal V(E) and HVR from PRE to N15-N19 were correlated (r = 0.51, P = 0.02) for the pooled data of LHTLc and LHTLi. These results suggest that enhanced hypoxic chemosensitivity contributes to increased exercise V(E) in normoxia following LHTL.

Effects of interval hypoxia on exercise tolerance: special focus on patients with CAD or COPD

“…That should contribute to improved exercise tolerance in subjects susceptible to oxygen desaturation, as it is the case in many patients with cardio-respiratory diseases [74]. However, there are only few data available showing that exercise ventilation is increased in normoxia after IH and that this increase is related to the enhanced HVR [51,52]. Townsend et al [52] demonstrated this occurrence in athletes, and we also found indirect indications for it in CAD patients [20].…”

“…Six or more repeated exposures to relatively severe hypoxia of ≥30 min stimulated HVR [28,35,[44][45][46][47][48][49]. An increased HVR could also be achieved by longer exposures to mild [52,54]. Whereas the effects of IH on exercise ventilation in older people with either cardiovascular diseases or low fitness level are ambiguous [18,20], in patients with mild COPD, a reduction in submaximal exercise ventilation has been observed after IH [27].…”

“…When returning to low altitudes, this increased HVR persists for hours to days [73]. Most of the studies using various protocols of IH also demonstrated an increase of the HVR [28,35,[44][45][46][47][48][49][50][51][52]. But a few days after IH, the HVR diminishes at least in healthy subjects [35, 48,50].…”

Effects of intermittent hypoxia on the cerebrovascular responses to submaximal exercise in humans

“…Some studies suggest that long-duration IH (e.g. live high, train low) rather than short-duration IH (*1 h bouts of hypoxia), and prolonged hypocapnic hypoxia is required to alter _ V E during exercise (Townsend et al 2005;Foster et al 2006). …”

Das Respiratorische System auf großer Höhe: Pathophysiologie und neue Therapieoptionen

“…Shekerdemian Es folgten teils kontroversielle Studien, die zeigten, dass nicht jeder gleich auf LHTL reagiert [36], das LHTL keinen Einfl uss auf den Lactat Metabolismus im Muskel hat [37], und dass LHTL zu einem verstärktem ventilatorischen response in submaximalen Leistungsebenen führt [38]. Aufgrund unterschiedlicher Methodik und untersuchter Population ergibt sich nur eine sehr geringe Vergleichbarkeit.…”