Any medical condition other than well controlled hypertension and mild diabetes.

Any medication known to influence breathing, sleep/arousal, or muscle physiology.

Claustrophobia.

Inability to sleep supine.

Allergy to any of the medications tested in the protocol.

History of kidney stones, hypercalcemia, primary hyperparathyroidism, sarcoidosis, hypervitaminosis D.

Individuals with underlying cardiac disease, such as arrhythmias.

Individuals taking psychiatric medications, such as an MAO-I, SSRI or SNRI, or any of the studied medications for medical care.

For women: Pregnancy.

Pulmonary hypertension

Severe OSA with a mean SaO2 lower than 88%

Pharmacological Activation of HMN for OSA