Effect of intermittent hypoxia on oxygen uptake during submaximal exercise in endurance athletes

Abstract

The purpose of the present study was to clarify the following: (1) whether steady state oxygen uptake (VO(2)) during exercise decreases after short-term intermittent hypoxia during a resting state in trained athletes and (2) whether the change in VO(2) during submaximal exercise is correlated to the change in endurance performance after intermittent hypoxia. Fifteen trained male endurance runners volunteered to participate in this study. Each subject was assigned to either a hypoxic group (n=8) or a control group (n=7). The hypoxic group spent 3 h per day for 14 consecutive days in normobaric hypoxia [12.3 (0.2)% inspired oxygen]. The maximal and submaximal exercise tests, a 3,000-m time trial, and resting hematology assessments at sea level were conducted before and after intermittent normobaric hypoxia. The athletes in both groups continued their normal training in normoxia throughout the experiment. VO(2) during submaximal exercise in the hypoxic group decreased significantly (P<0.05) following intermittent hypoxia. In the hypoxic group, the 3,000-m running time tended to improve (P=0.06) after intermittent hypoxia, but not in the control group. Neither peak VO(2) nor resting hematological parameters were changed in either group. There were significant (P<0.05) relationships between the change in the 3,000-m running time and the change in VO(2) during submaximal exercise after intermittent hypoxia. The results from the present study suggest that the enhanced running economy resulting from intermittent hypoxia could, in part, contribute to improved endurance performance in trained athletes.

“Live high–train low” using normobaric hypoxia: a double-blinded, placebo-controlled study

“…Although an unchanged economy following LHTL has been reported previously (39), it is difficult to explain the difference with the studies in which a reduced submaximal exercise VO 2 has been observed (19,28,29,52,53). Nevertheless, none of these studies provides an objective description of training intensity, which was either controlled by subjective feedback from the athletes (19,52) or not at all (28,29,53). It is therefore appealing to speculate that the open-label treatment and a concomitant placebo effect motivated LHTL subjects to train harder than their control counterparts, which in turn, may have improved running economy (15).…”

“…However, we found no indications for LHTL to affect whole-body VO 2 during submaximal cycling performed on numerous occasions. Although an unchanged economy following LHTL has been reported previously (39), it is difficult to explain the difference with the studies in which a reduced submaximal exercise VO 2 has been observed (19,28,29,52,53). Nevertheless, none of these studies provides an objective description of training intensity, which was either controlled by subjective feedback from the athletes (19,52) or not at all (28,29,53).…”

Effects of intermittent hypoxic training on cycling performance in well-trained athletes

“…In addition, not only HVR but also cardiovascular responses to hypoxia might be an underlying mechanism. HVR and systolic blood pressure responses were significantly increased after a 2-week intermittent hypoxic training program (5 sessions per week; 30 min per day; 70% _ VO 2 max ; 4,500 m), but decreased significantly in a normoxic control group (Katayama et al 2004). However, it could be that other peripheral muscle factors are associated with the changes observed following the training in hypoxia.…”

Effects of intermittent hypoxia on SaO2, cerebral and muscle oxygenation during maximal exercise in athletes with exercise-induced hypoxemia

“…Previous studies have used fixed F I O 2 values (Katayama et al 2001(Katayama et al , 2004, or a graded decline in F I O 2 Hinckson et al 2007;Julian et al 2004) as the hypoxic stimulus during IHE. Under poikilocapnic conditions i.e.…”