High Altitude Exposure Among People With Cardiovascular Conditions
Physiological acclimatization to altitude can impose an increased workload on the cardiovascular system. At high altitudes, considered those higher than 2500 m (~8200 ft) above sea level, physiologic responses may start to represent challenges for the human body.
High altitude is associated with progressive reduction in barometric pressure, air temperature, and humidity. A reduction in barometric pressure results in “hypobaric hypoxia.”
High altitude is associated with increases in systemic blood pressure (BP), both rest and exercise heart rate (HR)
Patients with coronary artery disease (CAD) may face added difficulties with high altitude because of already increased basal coronary flow at sea level, impairment in arterial elastic properties associated with atherosclerosis, and coronary microvascular dysfunction.
Different antihypertensive agents may have variable effects at altitude: carvedilol in normal subjects is associated with a significant reduction in the BP response to high altitude, but is associated with reduced arterial hemoglobin oxygen saturation and exercise tolerance.
High altitude exposure seems to pose a risk of cerebral ischemia for patients who already have suffered an ischemic stroke; both because of the direct effect of hypoxia, and due to a reduced cerebrovascular reactivity.
American College of Cardiology
January 19, 2018
Dr. Parker’s Commentary
The average airplane is pressurized to be the equivalent of 7000 feet, which isn’t much less than the altitudes that is the baseline for this study.
Interestingly, the study did not investigate the effect of aircraft pressurization levels on heart conditions; one is more likely to fly on an airplane than climb to high altitudes.
Heart patients need to take into account these considerations when flying. Perhaps they should drop the oxygen masks for us?
“If God had intended us to fly, he’d have never given us railways.”