To examine the effect of low estrogen and progesterone (as seen during the postmenopausal years) on breathing during exercise at sea level and at altitude. Further, to look specifically at the relationship between the concentration of estrogen and progesterone (2 main female sex hormones) on respiratory muscles.

2 day study: on the first day we do some lung function testing (seated breathing maneuvers) and a VO2max test on a bike. You will provide information on your menopause status so we can confirm you are one year without a period. On the 2nd day you first get a blood draw at the UBC hospital to measure hormone concentration in the blood. Then you walk 5 minutes to the lab where we attached 89 reflective markers to your chest wall and back so we can measure the volume changes in your lungs as you breathe. We also insert balloon catheters through your nose into the esophagus (like eating food) before cycling in room air and at simulated altitude.