Non-invasive Treatment for Long COVID (Post COVID-19 Condition) Brain Fog

The placebo visit will include 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air.

The progressive carbon dioxide visit will include a 60-minute progressive ramp which includes 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles.

The intermittent hypoxia exposure visit will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air.

Intervention will consist of 6 to 10 study visits (3-5 sessions/week) to be completed within 14 days. Subjects will will be given the progressive CO2 ramp protocol of 60-minute sessions, which will include 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles, for every visit during the 14 days.

Intervention will consist of 6 to 10 study visits (3-5 sessions/week) to be completed within 14 days. Subjects will will be given the intermittent hypoxia exposure protocol of 60-minute sessions, which will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air for every visit during the 14 days.

Intervention will consist of 6 to 10 study visits (3-5 sessions/week) to be completed within 14 days. Subjects will complete 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air (60 minutes) for every visit during the 14 days.