Other: Acute Placebo Visit

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

Other: Acute Progressive Carbon Dioxide

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.

Other: Acute Intermittent Hypoxia

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.

Other: Training: Progressive Carbon Dioxide Ramping

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.

Other: Training: Intermittent Hypoxic Exposure

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.

Other: Training: Placebo Control

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.