Colorectal cancer rates drop as altitude climbs. Men living above 1,000 meters have dramatically lower rates, nearly half, compared to those below 251 meters.
In 2021, researchers analyzed over 10 years of data across different elevations in Austria. They found that men living above 1000 meters had a 44% lower mortality rate from colorectal cancer, and women in the same altitude range had a 26% lower mortality rate from breast cancer compared to those living below 251 meters. Interestingly, the mortality dropped more steeply than incidence, suggesting that altitude may influence both tumor progression and survival outcomes.
In a 2015 study, researchers used data from the National Cancer Institute and found that for every 1,000-meter increase in elevation, lung cancer rates dropped by approximately 7.2 cases per 100,000 people, a 12.7% decrease relative to the average rate.
Elevation was identified as the second strongest predictor of lung cancer incidence, second only to smoking itself.
What happens to the body at high altitudes?
At high altitudes, the atmospheric pressure is lower, which means each breath contains fewer oxygen molecules than it would at sea level.
Although it may seem counterintuitive, the low oxygen levels may actually improve how much oxygen your tissues receive.
When oxygen drops, the body retains more carbon dioxide (CO2) in the blood. When CO2 levels in your blood rise, it causes a small drop in pH (this makes the blood slightly more acidic). The change in pH tells hemoglobin, the protein in red blood cells that carries oxygen, to let go of oxygen more easily.
When hemoglobin lets go of oxygen, it diffuses into the surrounding tissue, where it’s used by cells to make energy. So, high CO2 levels actually improve tissue oxygenation which in turn improve cellular metabolism and create conditions less favorable to cancer growth.
This is especially important in cancer. Tumors often grow in hypoxic (low-oxygen) environments. And improving oxygen delivery is an important step in cancer treatment?
When oxygen is low cells have to switch from using mitochondria to make energy to using glycolysis, a backup method that doesn’t need oxygen. This process is less efficient and creates lactate as a byproduct. Lactate acidifies surrounding tissues and further promotes tumor growth.
CO2 helps by improving tissue oxygenation. When cells receive adequate oxygen they can shift away from glycolysis towards mitochondrial respiration for more efficient energy production.
This shift reduces acidity, slows tumor growth, and helps restore healthy cell function.
Some other possible reasons cancer rates are lower at higher altitudes:
- Increased sun exposure leads to higher vitamin D levels which are associated with lower cancer rates
- Lower levels of air pollution and environmental toxins in some high-altitude regions
- Greater physical activity often associated with mountain living, which improves circulation and metabolic flexibility
- Some studies show that thyroid hormone output increases at high latitudes which improves energy production, induces cellular differentiation, and prevents cancerous changes
Some ways to increase CO2 and improve tissue oxygenation:
- Hiking, skiing, spending time at higher elevations
- Optimizing thyroid hormones
- Avoiding hyperventilation
- Bag breathing / buteyko breathing
- CO2 inhalers (Carbogenetics) / CO2 therapy
- Baking soda (sodium bicarbonate) baths
- Drinking sparkling water
- Optimizing b-vitamin intake, especially thiamine