Research on Room Oxygenation

ACT’s Altitude Simulation Systems are Based in Science
The technology and oxygen doses used in ACT systems are based in science. Unlike “oxygen companies” that only add a little oxygen, ACT’s oxygenation system maintains oxygen levels that are proven. Here are some studies showing how oxygenation and altitude simulation affect sleep, wellbeing and daytime performance.

Room oxygen enrichment improves sleep and subsequent day-time performance at high altitude

We carried out a randomized, double-blind trial at 3800 m altitude to test if a small degree of room oxygen enrichment at night improves the quality of sleeps, as well as performance and well-being the following day. Eighteen sea-level residents drove from sea level to 3800 m in one day and then slept one night in ambient air, and another night in 24% oxygen, the order is randomized. With oxygen enrichment, the subjects had fewer apneas (P < 0.01) and spent less time in periodic breathing with apneas (P < 0.01) than when they slept in ambient air. Subjective assessments of sleep quality were also significantly improved. The morning after oxygen-enriched sleep there was a lower acute mountain sickness score (P < 0.01) and a greater increase in arterial oxygen saturation from evening to morning (P < 0.05). The larger increases in arterial oxygen saturation from evening to morning suggest that the control of breathing may have been altered. Based on this research, installing an oxygen-enriched room system at high altitude is relatively simple and inexpensive, and it also shows promise for improving the well-being of both travelers and residents.

Respir Physiol. 1998 Sep;113(3):247-58.
Luks AM1, Van Melick H, Batarse RR, Powell FL, Grant I, West JB.

Effects of oxygen enrichment of room air on sleep patterns at high altitude


To explore how hypoxia circumstance affects sleep architecture and study the potential use of oxygen enrichment of room air at an altitude of 3700 m.

Oxygen concentration was raised to (24.30 +/- 0.88)% in a room with a dimension of 4.51 m x 3.32 m x 3.41 m. A selection of twelve men aged 18 to 20 years who had been at high altitude (3700 m above sea level) for 30 days slept one night in a room of ambient air and another night in the oxygen-enriched room the order being randomized. Their electroencephalograms (EEG) were recorded with CFM-8 polysomnography.

With oxygen-enriched than ambient air, significantly more time was spent in deep sleep (stages III and IV combined, also known as slow-wave sleep) [(19.33 +/- 4.85)% vs (13.67 +/- 3.75)%, P < 0.01 with paired comparisons]. The total sleep time [(500.83 +/- 32.94) min vs (470.67 +/- 27.43) min, P < 0.05] and the efficient sleep index [(90.33 +/- 2.06)% vs (85.50 +/- 3.34)%, P < 0.001] were also increased in oxygen-enriched air. No differences between ambient and oxygen-enriched air were found in sleep latency the time to fall asleep, the number of arousals and sleep shift (the time spent awake after falling asleep), but there was a trend toward fewer of these with oxygen treatment.

There will be a promise for improving sleep quality, well-being and work capacity when installing an oxygen-enriched room at high altitude which is relatively simple and inexpensive.

Ha ZD1, He TH, Zhang XZ, Wang W, Ma Y, Jian XQ.
Author information Zhonghua Nei Ke Za Zhi. 2004 May;43(5):368-70.

Nocturnal oxygen enrichment of room air at 3800-meter altitude improves sleep architecture

High altitudes are known to impair sleep, and this may be a contributing factor to reduced work efficiency, general malaise, and the development of acute mountain sickness (AMS). Nocturnal room oxygen enrichment at 3800 m has been shown to reduce the time spent in periodic breathing and the number of apneas, to improve the quality of sleep, and to reduce the AMS score. The present study was designed to evaluate the effect of oxygen enrichment to 24% at 3800 m (lowering the equivalent altitude to 2800 m) on sleep architecture. Full polysomnography and actigraphy were performed on twelve subjects who ascended in one day to 3800 m and slept in a specially designed room that allows oxygen enrichment or ambient air conditions in a randomized, crossover, double-blind study.

The results showed that the subjects spent a significantly greater percentage of time in deep sleep (stages III and IV combined, or slow-wave sleep) with oxygen enrichment versus ambient air (17.2 +/- 10.0% and 13.9 +/- 6.7%, respectively; p < 0.05 in paired analysis). There was no differences between treatments seen with subjective assessments of sleep quality or with the subject’s assessment of the extent to which they suffered from AMS. This study suggests that alleviating hypoxia may improve sleep quality and provides further evidence of improved sleep as a result of oxygen enrichment at 3800 m.

High Alt Med Biol. 2001 Winter;2(4):525-33.
Barash IA1, Beatty C, Powell FL, Prisk GK, West JB.
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Six percent oxygen enrichment of room air at simulated 5,000 m altitude improves neuropsychological function

Cognitive and motor function are known to deteriorate with the hypoxia accompanying high altitude. This poses a substantial challenge to the efficient operation of high altitude industrial and scientific projects. To evaluate the effectiveness of enriching room air oxygen by 6% at 5,000 m altitude in ameliorating such deficits, 24 unacclimatized subjects (16 males, 8 females; mean age 37.8, range 20 to 47) underwent neuropsychological testing in a specially designed facility. The facility is at 3,800 m that can simulate an ambient 5,000 m atmosphere and 6%  enrichment at 5,000 m. Each subject was tested in both conditions in a randomized, double-blinded fashion. The 2-h test battery of 16 tasks assessed various aspects of motor and cognitive performance. Compared with simulated breathing air at 5,000 m, oxygen enrichment resulted in quicker reaction times, higher arterial oxygen saturations (93.0 vs. 81.6%), improved hand-eye coordination, and a more positive sense of well-being (on 6 of 16 scales), each significant at the p < 0.05 level. Other aspects of neuropsychological function were not significantly improved by 6% additional oxygen. High Alt Med Biol. 2000 Spring;1(1):51-61.

Six percent oxygen enrichment of room air at simulated 5,000 m altitude improves neuropsychological function.

Gerard AB1, McElroy MK, Taylor MJ, Grant I, Powell FL, Holverda S, Sentse N, West JB.
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Nocturnal O2 enrichment of room air at high altitude increases daytime O2 saturation without changing control of ventilation

In a randomized, double-blind study, 24 sea-level residents drove to 3,800-m altitude in 1 day.  They then slept the first night in either ambient air or 24% oxygen. The second night in the program they  received the treatment  that they did not receive on the first night. Oxygen enrichment, compared with ambient air, resulted in significantly fewer apneas, and significantly less time spent in periodic breathing during the night. The increase in SaO2 between evening and morning was significantly higher after sleeping in the oxygen-enriched atmosphere, compared with ambient air. However, this significant improvement in SaO2 did not persist into mid-day. The overnight treatment did not alter the ventilatory response to hypoxia or to carbon dioxide as measured the following morning. The results suggest that the elevation in SaO2 following overnight oxygen enrichment is possibly not due to a change in the control of ventilation, but perhaps to the differences in subclinical lung pathology. High Alt Med Biol. 2000 Fall;1(3):197-206.

Nocturnal O2 enrichment of room air at high altitude increases daytime O2 saturation without changing control of ventilation.

McElroy MK, Gerard AB1, Powell FL, Prisk GK, Sentse N, Holverda S, West JB, Author information
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Oxygen enrichment of room air to improve well-being and productivity at high altitude

Increasingly, commercial activities, such scientific facilities, mines,  and telescopes, are being placed at very high altitudes, up to 5,000 m. Workers frequently commute to these locations from much lower altitudes, and even from sea level. In addition, large numbers of people permanently live and work at high altitudes. The hypoxia of high altitude impairs sleep quality, productivity, mental performance, and general well-being. It has recently become feasible to raise the oxygen concentration of room air by injecting oxygen into the air conditioning. This is incredibly effective at reducing the equivalent altitude. For example, increasing the oxygen concentration by 1% (e.g., from 21% to 22%) reduces the equivalent altitude by about 300 m. In other words, a room at an altitude of 4,500 m containing 26% oxygen is effectively at the altitude of 3,000 m. Enrichment of oxygen has now been tested in several studies and has been shown to improve cognitive function and sleep quality. The fire hazard is less than in air at sea level. This innovative technique promises to improve productivity and well-being at high altitude.

Oxygen enrichment of room air to improve well-being and productivity at high altitude.
West JB
Author information
Department of Medicine, University of California San Diego, La Jolla, CA 92093-0623, USA. [email protected]

Effect of high terrestrial altitude and supplemental oxygen on human performance and mood

Sustained exposure to high terrestrial altitudes is associated with mood changes, cognitive decrement, and acute mountain sickness (AMS). Such impairment in aviators could be a safety hazard. Thirteen male soldiers, ages 19-24, ascended in 10 min from sea level to 4,300 m (simulated), and remained there 2.5 days. Subjects completed a test battery consisting of nine cognitive tests, a mood scale, and an AMS questionnaire four times a day. During one test session per day, subjects breathed 35% oxygen instead of ambient air. Analysis revealed transient deficits on altitude day 1 for three cognitive tasks. Most of the tasks displayed a persistent training effect. The subjects that were sick had moods that were more negative and their performance improvement less. On altitude day 1, oxygen administration improved performance on two cognitive tests and one mood subscale. Following rapid ascent to 4,300 m, performance is most affected during the first 8 h. Individuals affected by AMS tend to improve more slowly in performance and have more negative moods than those who feel well.

Aviat Space Environ Med. 1992 Aug;63(8):696-701.
Crowley JS1, Wesensten N, Kamimori G, Devine J, IWanyk E, Balkin T.
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U.S. Army Aeromedical Research Laboratory, Fort Rucker, AL 36362.

Potential use of oxygen enrichment of room air in mountain resorts

Oxygen enrichment of room air has proved to be valuable for people who need to work at altitudes of 4000 m and above. In this study the feasibility of using the same technique in ski and other mountain resorts at the lower altitudes of 2500 to 4000 m is considered. While many people find these altitudes invigorating, some are distressed by the hypoxia, especially at night. The analysis shows that all resorts up to an altitude of 3250 m (10,600 ft) can have the equivalent altitude reduced to 1000 m (3280 ft) by oxygen enrichment without incurring a fire hazard. (The equivalent altitude is that which provides the same inspired P(O2) during air-breathing.) Even resorts as high as 4250 m can have the equivalent altitude safely reduced to 1500 m, that is,  a lower altitude than Denver, Colorado. This application of oxygen enrichment is likely to be most valuable for improving sleep and assisting in the initial acclimatization process.

High Alt Med Biol. 2002 Spring;3(1):59-64.

Potential use of oxygen enrichment of room air in mountain resorts.
West JB
Author information
Department of Medicine, University of California San Diego, La Jolla CA 92093-0623, USA. [email protected]

Commuting to high altitude. Recent studies of oxygen enrichment

Additional studies have been carried out on the potential value of oxygen enrichment of room air for commuters to high altitude. New ways of providing oxygen-enriched spaces for sleeping and working are being tested at the California Institute of Technology where a radiotelescope is being designed for an altitude of 5,000 m in north Chile. The modules are containers similar those used on container ships. They are fitted in California and then sealed and transported to the telescope site in Chile. The result is a turnkey facility which shows promise for field studies. Oxygen is provided by oxygen concentrators, different modules are used for living, sleeping, and laboratory quarters. Two extensive experiments on oxygen enrichment were carried out at the University of California White Mountain Research Station, altitude 3,800 m, in the summer of 1998.

The first study was dedicated to the mechanism for the increase in arterial oxygen saturation on the day after sleeping in an oxygen-enriched atmosphere as compared with sleeping in ambient air (5). Possible mechanisms include less fluid accumulation in the lung associated with acute mountain sickness, or a change in the control of ventilation. A double blind study was then carried out of the effects of sleeping in oxygen enrichment on both the ventilatory response to hypoxia and to carbon dioxide. In a related study, subjects who had been at an altitude of 3,800 m for two days, and were partially acclimatized, were studied at a simulated altitude of 5,000 both were breathing ambient air and 27% oxygen. Studies were done at 3800 m altitude by enriching the atmosphere of the test room with appropriate amounts of nitrogen or oxygen. An extensive series of neuropsychological tests were carried out with the objective of determining which features of CNS function were improved by oxygen enrichment at an altitude of 5,000 m.

West JB1. Department of Medicine, University of California San Diego, La Jolla 92093-0623, USA.
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Adv Exp Med Biol. 1999;474:57-64.

Oxygen enrichment of room air to relieve the hypoxia of high altitude

There has recently been increasing commercial activity at altitudes of 3500-6000 m. Examples include new mines in northern Chile at altitudes of about 4500 m. Because the workers come from sea level, intolerance of the high altitude is a major problem. This degree of hypoxia reduces sleep quality, work capacity, and mental efficiency. One original solution is to raise the PO2 of the room air by adding oxygen to the room ventilation. This strategy is remarkably effective. For example, at altitudes of 4000-5000 m, increasing the O2 concentration by 1% (e.g. from 21 to 22%) reduces the equivalent altitude by about 300 m. Therefore raising the O2 concentration by 5% at the new mines reduces the equivalent altitude to 3000 m which is easily tolerated. The introduction of oxygen concentrators (molecular sieve) that require only electrical power makes O2 enrichment feasible. Fire hazards are less than in air at sea level. Everyone now expects that the ventilation of a room will provide a comfortable temperature and humidity. Control of the oxygen concentration can be regarded as a further logical step in one’s control of their environment.

Respir Physiol. 1995 Feb;99(2):225-32.
West JB
Author information
Department of Medicine 0623A, University of California San Diego, La Jolla 92093-0623, USA.