Is acute mountain sickness related to trait anxiety? A normobaric chamber study.

INTRODUCTION: Some mountaineers are more prone to the occurrence of acute mountain sickness (AMS) than others. State anxiety during altitude exposure might be associated with AMS development. We hypothesized that trait anxiety might be higher in AMS cases compared to non-AMS cases. The aim of the present study was to study the relationship between AMS development and trait anxiety. METHODS: In an observational study design, AMS incidence during a 12-hour exposure to normobaric hypoxia (FiO2=12.6%, equivalent to 4500m) was determined by the Lake Louise Scoring System. Trait anxiety (State Trait Anxiety Inventory) and confounding variables were assessed in a follow-up questionnaire (37months after hypoxic exposure). RESULTS: Twenty nine participants returned the follow-up questionnaire. AMS incidence was 38%. Both unadjusted and adjusted logistic regression analyses did not reveal trait anxiety as a significant variable in relation to AMS. DISCUSSION: Based on the findings of this preliminary study, there is no evidence that AMS development under normobaric conditions is related to trait anxiety. Differences to previous studies might be explained by the type of hypoxia, by different sample characteristics and by considering sleep disturbances in the calculation of the AMS score. However, future studies with larger sample sizes may help to clear the relationship between AMS development and the personality factor anxiety.

Regional differences in the cerebral blood flow velocity response to hypobaric hypoxia at high altitudes.

Symptoms of acute mountain sickness (AMS) may appear above 2,500 m altitude, if the time allowed for acclimatization is insufficient. As the mechanisms underlying brain adaptation to the hypobaric hypoxic environment are not fully understood, a prospective study was performed investigating neurophysiological changes by means of near infrared spectroscopy, electroencephalograpy (EEG), and transcranial doppler sonography at 100, 3,440 and 5,050 m above sea level in the Khumbu Himal, Nepal. Fourteen of the 26 mountaineers reaching 5,050 m altitude developed symptoms of AMS between 3,440 and 5,050 m altitude (Lake-Louise Score ⩾3). Their EEG frontal beta activity and occipital alpha activity increased between 100 and 3,440 m altitude, i.e., before symptoms appeared. Cerebral blood flow velocity (CBFV) in the anterior and middle cerebral arteries (MCAs) increased in all mountaineers between 100 and 3,440 m altitude. During further ascent to 5,050 altitude, mountaineers with AMS developed a further increase in CBFV in the MCA, whereas in all mountaineers CBFV decreased continuously with increasing altitude in the posterior cerebral arteries. These results indicate that hypobaric hypoxia causes different regional changes in CBFV despite similar electrophysiological changes.

Right temporal cerebral dysfunction heralds symptoms of acute mountain sickness.

Acute mountain sickness (AMS) can occur during climbs to high altitudes and may seriously disturb the behavioral and intellectual capacities of susceptible subjects. During a Himalayan expedition 32 mountaineers were examined with electroencephalography (EEG) and transcranial doppler sonography (TCD) to assess relative changes of middle cerebral artery velocity in relation to end-expiratory CO2 (EtCO2), peripheral saturation (SaO2), and symptoms of AMS. We tested the hypothesis that O2 desaturation and EtCO2 changes precede the development of AMS and result in brain dysfunction and compensatory mechanisms which can be measured by EEG and TCD, respectively. Contrary to our hypothesis, we found that subjects who later developed symptoms of AMS between 3,440 m and 5,050 m altitude exhibited an increase of slow cerebral activity in the right temporal region already at 3,440 m. Cerebral blood flow increased in these mountaineers in the right middle cerebral artery at 5,050 m. These findings indicate that regional brain dysfunction, which can be documented by EEG, heralds the appearance of clinical symptoms of AMS.

Vacation at moderate and low altitude improves perceived health in individuals with metabolic syndrome.

BACKGROUND: Recent data suggest that vacation may improve cardiovascular health, an effect possibly moderated by altitude. The aim of the present study was to study the effect of a 3-week vacation at moderate and low altitude on perceived health in individuals with increased cardiovascular risk. METHODS: Seventy-two overweight males, both occupationally active and retired (mean age=56.6 +/- 7.2 years), with signs of metabolic syndrome were randomly assigned to identical sojourns at either moderate (1,700 m) or low (300 m) altitude and engaged in four 3- to 4-h heart-rate-controlled hiking tours per week. Perceived health was measured 2 weeks before vacation, at the beginning and end of vacation, and 7 weeks after vacation. RESULTS: Fitness, recreational ability, positive and negative mood and social activities improved during vacation, independent of altitude and occupational status, although the day-to-day improvement in quality of sleep was delayed at moderate altitude. During the follow-up examinations, improvements in all reported aspects of health except for social activities were maintained. In comparison to retired individuals, active individuals showed a greater long-term improvement in social activities. CONCLUSION: Vacation positively affects perceived health independent of altitude or occupational status in generally inactive overweight males.