Effects of Cyclic Variations in Altitude Conditioning (CVAC) on Wellness and Activity Measures (CVAC)

Cyclic Variation in Altitude Conditioning (CVAC) is a new technique that uses a pod-like device to expose users to controlled fluctuations in air pressure. It is designed to promote quicker altitude acclimatization, thus promoting improvements in exercise capacity at altitude and, possibly, at sea level. However, over the past few years, anecdotal stories from users of the device suggest that the CVAC treatments might be causing changes beyond the expected endurance exercise performance benefits. Therefore, the purpose of the study is to obtain data on some of the previous anecdotal claims regarding the device (e.g. increases in strength, improved glucose tolerance, reduction of neuropathic pain and decreased joint swelling) as well as to obtain broad questionnaire data in order to identify more specific variables to investigate in future studies.

Sham altitude changes - The CVAC device consists of a small pod-like chamber attached to a computer system that controls a strong pump that can draw air rapidly out of the chamber to increase the simulated altitude. The sham-treated group (SH) was exposed to regular, slowly-fluctuating pressures that reached a maximum altitude of 607 m for all 30 sessions. Sham sessions mimicked the noises and initial pressure-change sensations created in the active sessions, thus giving naıve subjects the impression that they were experiencing altitude treatment. All subjects were blind to their elevation throughout the intervention.

Cyclic Hypobaric Hypoxia (CHH) subjects were given 40 min sessions inside the CVAC device per day (two 20 min sessions sequentially per day), 3 days a week for 10 weeks, for a total of 30 sessions or 20 hours. After familiarization sessions, pre-programmed sessions were administered, progressing from Tier 1 to 5. Subjects rotated through three pre-programmed sessions per Tier and each session varied the pattern and rate of hypoxic fluctuations, so that subjects would experience a constantly changing stimulus at each elevation. Five weeks were allotted to progress from Tier 1 (3048 m) to Tier 4 (5486 m). At Tier 5 (6096 m), there was an additional 5 weeks of exposure.

Glucose measurements were made at baseline, 3, 6, & 10 weeks. Blood was collected consistently after a 10-12 h fast the morning after a CVAC session (except for baseline).

Inclusion Criteria: Healthy middle aged men at risk for metabolic syndrome Exclusion Criteria: Uncontrolled hypertension, sensitive ears, anything that would preclude person from sustaining rapid pressure changes