Sleep Apnea in Elderly

The ventilatory effects of brief hyperoxia will be assessed by analyzing control breaths on room air immediately preceding the hyperoxic exposure, and comparing with the primary end-point, nadir minute ventilation breath, immediately following the brief hyperoxic exposure

Participants with sleep apnea will ingest capsules containing either placebo or acetazolamide 500 mg twice a day for 5 days. On the final 2 consecutive nights while still on ACZ, the investigators will perform i) physiology tests and ii) in-lab follow-up PSG.

Elderly males with sleep apnea and adequate testosterone levels will ingest placebo vs finasteride, at 5 mg a day for 1 month (mo). After 1 mo, while still on the drug, on the final 2 consecutive nights, the investigators will perform i) physiology tests and ii) in-lab follow-up PSG. Blood tests will be performed to check sex hormone levels. A washout period of 1 month prior to cross-over to the alternate arm (placebo).