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Use of Intermittent Hypoxic Training Exposure (IHTIHE) is relatively new in the west, but the USSR (and later CIS) has been researching and using IHT IHE since the 1930's. Usage includes sports, altitude acclimatization, and treatment of clinical disorders, including chronic lung diseases, bronchial asthma, hypertension, diabetes mellitus, Parkinson’s disease, emotional disorders, and even radiation toxicity.

There appear to be three mechanisms underlying the effects of IHTIHE: regulation of respiration, mitochondrial respiration, and free-radical production.

The research shows that there is wide individual variation in the response to IHT IHE and altitude. This variation exists in both humans and animals, and appears to be due to mechanisms beyond simple iron insufficiency.

* Studies in rats suggest that continuous exposure to altitude reduces anti-oxidant defenses, but IHT IHE improves them.* Other studies in rats indicate that IHT IHE changes the ratio of fat to protein burning in favor of fats by 80%.* A study of workers that cleaned up after Chernobyl nuclear reactor explosion showed that they had higher levels of oxidant stress where higher than normal. Exposing the workers to IHT IHE of 3x (5 min 7-8% [28,000+ ft] O₂ with 5 min normal air) for 14 days significantly reduced the oxidant stress. * Studies have shown IHT IHE reduces the oxidant stress associated with bronchial asthma. (There were large variations in individual response, and more research is needed.)* Recent studies indicate that IHT IHE stimulates NO (Nitric Oxide) production, with the excess stored in the vascular walls. This improves blood pressure. * Research indicates that there is a very wide variability in the response to altitude (IHT IHE or other) and tolerance of extreme hypoxia. Future research may provide methods of overcoming the lack of response in some individuals.

* Research<ref name="jack"/> using highly trained runners showed no running improvement with IHTIHE. However, this study used IHT IHE for 4 weeks and had O₂ saturation values of 89.9, 86.3, 85.9, and 81.4 for each week. The value of IHT IHE is dependent upon the O₂ saturation levels, with little effect until values under 89%<ref name="HTI"/>. The athletes in the study therefore only received significant hypoxia for about one week. The athletes were given 5 min hypoxic, 5 min normal for 70 minutes total for five days per week, 4 weeks total. * A similar research<ref name="junis"/> study showed a significant improvement in 3K running performance. This study used 90 minutes of IHT IHE (5 hypoxic:5 normal) for 15 days over a three week period, using 13,000 feet at the start to 19,000 feet at the end. * A study<ref name="EPO"/> looking at Hypoxia EPO, a hormone that stimulates red blood cell production showed a ~50% increase in EPO from 4 hours of IHT IHE or 2 hours of continuous hypoxia, but no response from 5 minutes or 1 hour. The IHT IHE was a simulated altitude of 18,000 ft

* IHT IHE increased lung force in asthmatic and non-asthmatic athletes. There was no deterioration in asthma status from the trial, and half of the asthmatics reported a reduction in the need for medication. The trial used 15 sessions over three weeks, with each session being 5 min hypoxia followed by 5 min normal air, repeated for 60 minutes. The hypoxia was equivalent to 22,500 ft.<ref name="asthmatic"/> Other studies have reported a similar improvement in asthma, with reduced attacks, reduced severity of attacks and reduced need for medication.  ==IHE and Live High, Train Low==Some literature considers sleeping at altitude (or with low oxygen levels) to be 'IHT'. This Wiki uses IHT to be separate from LHTL and to mean shorter periods than overnight sleep and generally at much lower oxygen concentrations.

<ref name="asthmatic">http://www.hypoxico.com/images/pdfs/Does_IHT_effect_the_lung_function_of_asthmatic_athletesDoes_IHE_effect_the_lung_function_of_asthmatic_athletes.pdf Does IHT IHE effect the lung function of asthmatic athletes</ref><ref name="junis">http://www.altitudecentre.com/images/Lincoln_Double_BlindIHT_Rep_2003Lincoln_Double_BlindIHE_Rep_2003.pdf Intermittent Hypoxic Training in Endurance Athletes</ref>