Mild Hypoxia of a Skydiver Making Repeated, Medium-Altitude Aircraft Exits.
Level 4 - case-series / case-control
Single-subject case report
PubMed 31980051 · doi:10.3357/AMHP.5497.2020
What was done
A healthy 50-year-old male skydiver completed four unpressurized aircraft exits (two jumps per day over two consecutive days) between 13,500 and 14,000 ft (4,115 and 4,267 m) pressure altitude without supplemental oxygen. Heart rate and peripheral oxygen saturation (SpO₂) were monitored continuously using a helmet-mounted biomonitoring device (SPYDR), and subjective symptoms were recorded.
What was found
The subject was mildly hypoxic at jump altitude (SpO₂ < 90%) across all four jumps. SpO₂ did not return to normal levels until the participant was under canopy. After the second jump on both days, the participant experienced dizziness and lightheadedness, which he noted occurring roughly once every five jumps. The abstract reports no exact numeric pulse values or exact SpO₂ percentages beyond the < 90% threshold.
Why it matters
Civilian skydivers routinely exit at medium altitudes without supplemental oxygen, and undetected mild hypoxia during ascent and exit could cause cognitive impairment or procedural errors.
Limits
This is a single-subject case report (n = 1), preventing generalization across different ages, ascent profiles, or physical fitness levels. Cognitive function and procedural error rates were not directly tested, and precise quantitative oxygen saturation curves and pulse rates were not reported in the abstract.
Cited by
- supports In aviation, occupants cannot fly above 14,500 feet without supplemental oxygen due to physiological requirements.