Healthy subjects without a history of coronary artery disease will undergo computer-controlled gas challenges.

Healthy subjects without a history of coronary artery disease will undergo computer-controlled gas challenges.

Healthy subjects without a history of coronary artery disease will undergo computer-controlled gas challenges.

Healthy subjects without a history of coronary artery disease will undergo computer-controlled gas challenges.

RespirAct device-based computer-controlled gas delivery at different concentrations as per protocol

1. Saturation of peripheral oxygen as percentage
2. Heart rate as beats per minute
3. Noninvasive blood pressure as mmHg
4. Partial pressure of oxygen as mmHg
5. Partial pressure of carbon dioxide as mmHg

1. Chest pain
2. Headache
3. Dizziness
4. Confusion
5. Fatigue
6. Upset stomach
7. Nausea
8. Vomiting

Procedure tolerability will be evaluated by the number of participants completing day 1 and day 2 of study participation.

Participants will be asked to rate their comfort level for breathing from the mask and the gas changes as Painful, Not Comfortable, Tolerable for short time, tolerable for entire study, or comfortable.