TELLURIDE – According to researchers at University of Colorado School of Medicine and Harvard School of Global Health, living at high altitudes may reduce the risk of dying from heart disease, and improve chances of living longer.
The study, published on the American Association for the Advancement of Science website EurekAlert.org, analyzed death certificates from every American county over the course of four years, taking into account the cause of death, socio-economic factors and other issues.
Researchers found that of the 20 counties with the highest life expectancy, 16 (11 for men and five for women) were located in Colorado and Utah, at a mean elevation of 5,967 feet in elevation. In these 16 counties, men lived between 75.8 and 78.2 years and women lived from 80.5 to 82.5 years.
Compared with those living near sea level, men lived 1.2 to 3.6 years longer and women .5 to 2.5 more years.
Telluride’s Institute for Altitude Medicine Executive Director Dr. Peter Hackett said a study like this one completed needs to have controls for variables among those living at altitude, ranging from less obesity to less smoking and less heart disease, for effective findings. Of the study, he said, “They tried to control for most variables, and they did a pretty good job.
“It’s not a perfect study, but they collected as much data as they could. As it turns out, there is something about the lack of oxygen at high altitude that is actually good for the heart.”
Hackett and researchers aren’t exactly sure why less oxygen benefits the heart at higher altitudes, but point to a number factors that may explain the findings.
“Lower oxygen levels turn on certain genes, and we think those genes may change the way heart muscles function,” Benjamin Honigman, professor of Emergency Medicine at UCSM and director of the Altitude Medicine Clinic, said in the report. “They may also produce new blood vessels that create new highways for blood flow into the heart.”
Adding to that, Hackett said, is data from South America that shows people living at 14,000 feet have a higher number of blood vessels in their hearts than those living at low elevations. When the heart has more blood vessels, he said, blood is able to flow into the heart more effectively, especially if there is a clot.
“It’s very impressive to see how many more blood vessels they had in their heart. This wasn’t done at 8,000 feet, it was done at 14,000 feet, but there is no reason to think that people living at 8,000 feet wouldn’t have some of that,” Hackett said.
Besides creating more blood vessels, Hackett said the findings could also be related to more vitamin D synthesis, more ultraviolet radiation and even to the fact that various oxygen levels cause different metabolism rates of cholesterol.
Hackett said he found it “curious” that living at higher attitudes does not reduce the instance of strokes in the study, which tells researchers that the beneficial effects of living at altitude are heart-specific, as opposed to beneficial to blood vessels in general.
One thing researchers have not sorted out is how long someone must live at a high altitude for its benefits to take effect, but Hackett believes if one is born and raised at a high altitude, he or she is probably more at an advantage than someone who moved to Telluride at age 60.
The study also showed that altitudes above 4,900 feet were detrimental to those suffering from chronic obstructive pulmonary disease.
“Even modestly lower oxygen levels in people with already impaired breathing and gas exchange may exacerbate hypoxia and pulmonary hypertension [leading to death],” the study concluded.
“You can’t smoke and not exercise and come here to live longer,” Hackett said in Telluride.
The overall findings could lead researchers to conduct even more studies on heart disease to improve treatment.
“If living in a lower-oxygen environment such as in our Colorado mountains helps reduce the risk of dying from heart disease, it could help us develop new clinical treatments for those conditions,” Honigman said.