Mood disturbance during cycling performance at altitude

Elite performance can require athletes to perform optimally in hypoxic conditions. Research findings show that exercising in hypoxia can produce a stress response, characterised by increased negative mood, and relatively poor performance. Recent research suggests that depressed mood is the most influential mood dimension (Lane and Terry, 2000), and that individuals reporting depressed mood tend also to report increased fatigue, confusion, anger, and tension and reduced vigour. PURPOSE: The purpose of the present study was to investigate mood changes during a two-hour cycling test during hypoxic and normoxic conditions. A second aim was to investigate mood dynamics that lead to depressed mood. METHODS: Eight male elite cyclists (Age: 26.23  6.74yrs; VO2max: 67.4  6.3 ml.kg-1.min-1) volunteered to participate in the study. Participants performed two 50-mile cycle bouts on a stationary cycle ergometer rig. Trials were randomly assigned from normobaric normoxia and normobaric hypoxia (FIO2 ≈15.3%, a simulated altitude of 2,500 metres), and were separated by two weeks. Both cycle bouts were performed at an intensity equivalent to lactate threshold (previously determined in normobaric normoxia). Mood was assessed before, after one hour, after two hours and on completion of the 50 mile ride using the 24-item Brunel Mood Scale (Terry, Lane, Lane, & Keohane, 1999), which assesses anger, confusion, depression, fatigue, tension, and vigor. RESULTS: Repeated measures ANOVA (time x condition) results showed that fatigue increased significantly more at altitude than at sea level (F 1,7 = 5.73, p < .05, Eta2 = .45). Other unpleasant mood states also increased more during the hypoxic condition than the normoxic condition. Effects were moderate, although not statistically significant, for anger (F 1,7 = 3.87, p = .09, Eta2 =.36), confusion (F 1,7 = 2.21, p = .18, Eta2 =.24), depression (F 1,7 = 2.88, p = .13, Eta2 =.29), and tension (F 1,7 = 3.09, p = .12, Eta2 = .31). Vigor scores decreased more during the altitude ride (F 1,7 = 2.26, p = .18, Eta2 = .25). An examination of mood dynamics indicated that increases in depressed mood followed an exponential increase in fatigue, rather than the other way around, and that once depressed mood was activated it was associated with increased anger, confusion, and tension and reduced vigor. CONCLUSIONS: Findings lend support to the notion that, compared to sea level, performing intense exercise at altitude is associated with greater mood disturbance. It is suggested that future research investigates the post-exercise duration of such mood disturbance and the interplay between mood dynamics and the type of coping strategies used by athletes during intense exercise.