In general, IHT contributes to improved immunological status. The occurrence of allergies and inflammatory diseases decreases. This has been observed in continuous exposure to altitude, as well as with IHT. Studies have been able to show improvements to conditions of an inflammatory nature, such as arthritis, asthma, allergic rhinitis, autoimmune thyroiditis and inflammatory skin diseases.

Even the difficult-to-treat and disabling disease rheumatoid arthritis showed a positive response, with seven out of 10 patients receiving IHT showing less inflamed joints, reduced pain and morning stiffness and reduced need for medication. All patients reported improved mood, sleep and appetite and increased . physical activity.

Asthma has received particular attention, with several studies showing significant improvement. Observations made in the Netherlands have shown that asthmatics treated in climatic chambers that simulated altitudes of 1500 to 2550 metres improved rapidly, and with 60 to 100 treatments were 'cured'. This certainly fits with the common observation that asthmatics, despite their obvious fears about altitude, usually have less asthma and do much better at altitude. I have taught the Buteyko method for the past nine years. This highly successful method (also originating in Russia) teaches that hyperventilation and loss of carbon dioxide (which is anti- inflammatory and bronchodilator) worsen the asthmatic condition.Inflammation in the lungs is one reason asthmatics hyperventilate.

Another perpetuating factor to hyperventilation could be inefficient oxygen metabolism. Until this is improved, the asthmatic will continue to hyperventilate. The improved oxygen capacity observed after adaptation to hypoxia results in the oxygen required by the body being supplied with less volume of air needing to be taken in and less hyperventilation taking place. Recent experiences with patients on artificial ventilation indicate that the stress of breathing itself might adversely affect susceptible airways. Lower ventilation levels are associated with a 30 per cent lower mortality rate in patients with severe lung disease.

IHT and COVID - 19

In COVID-19 pandemic South America and Tibet have demonstrated lower COVID-19 transmission due to low oxygen environment.

Scientific researches proved that low oxygen environment can help prevent the virus that causes COVID-19 (SARS-CoV-2) from infecting and replicating within previously healthy cells.

Thanks to the blistering rate of research, scientists quickly discovered that infection occurs when a spike protein on the virus itself binds to a protein on the surface of human cells called ACE2. This binding triggers a signalling cascade that ultimately fuses the viral and human cells together and allows the virus to enter its genetic material into the human cell, infecting it. The heart and kidney in particular express large amounts of ACE2 on their cells, which might explain why the virus can have such a wide impact.

In one of the most comprehensive studies of its kind, researchers at the University of Colorado School of Medicine in partnership with the Harvard School of Global Health have found that people living at higher altitudes have a lower chance of dying from ischemic heart disease and tend to live longer than others.

"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. Lower oxygen levels turn on certain genes and we think those genes may change the way heart muscles function. They may also produce new blood vessels that create new highways for blood flow into the heart."

said Benjamin Honigman, MD, professor of Emergency Medicine at the CU School of Medicine and director of the Altitude Medicine Clinic

Another explanation, he said, could be that increased solar radiation at altitude helps the body better synthesize vitamin D which has also been shown to have beneficial effects on the heart and some kinds of cancer.

The study was recently published in the Journal of Epidemiology and Community Health.

At the same time, the research 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 said.

Honigman, senior author of the study, along with researchers that included Robert Roach, PhD, director of the School of Medicine's Altitude Research Center, Deborah Thomas, PhD, a geographer at the University of Colorado Denver and Majid Ezzati of the Harvard School of Global Health, spent four years analyzing death certificates from every county in the U.S. They examined cause-of-death, socio-economic factors and other issues in their research.

They found that of the top 20 counties with the highest life expectancy, eleven for men and five for women were located in Colorado and Utah. And each county was at a mean elevation of 5,967 feet above sea level. The men lived between 75.8 and 78.2 years, while women ranged from 80.5 to 82.5 years.

Compared to those living near sea-level, the men lived 1.2 to 3.6 years longer and women 0.5 to 2.5 years more.

Despite these numbers, the study showed that when socio-economic factors, solar radiation, smoking and pulmonary disease were taken into account, the net effect of altitude on overall life expectancy was negligible.

Still, Honigman said, altitude seems to offer protection against heart disease deaths and may also play a role in cancer development.

Colorado, the highest state in the nation, is also the leanest state, the fittest state, has the fewest deaths from heart disease and a lower incidence of colon and lung cancer compared to others.

"We want to now look at these diseases in a more focused way so we can see the mechanisms behind hypoxia and why they affect the body the way they do. This is a public health issue in Colorado and the mountain West. We have more than 700,000 people living at over 7,000 feet above sea level. Does living at altitude change the way a disease progresses? Does it have health effects that we should be investigating? Ultimately, we hope this research will help people lead healthier lives."

Honigman said.