It is quiet in the test participant facility of the DLR Institute of Aerospace Medicine. In each of the individual rooms there is a participant in the ChronOx study, which the Dutch doctoral student is conducting for his doctorate. For this study, Titiaan Post was looking for average sleepers. Not those who turn night into day, nor those who prefer to wake up before the sun. For him, it is important that his test participants are as average as possible so that he can answer one question: Is hypoxia, i.e. the lack of oxygen, also one of the timers for sleep and does it influence the rhythm of the human body? The ChronOx study conducted for this purpose, in which test subjects live and sleep under reduced oxygen levels at DLR’s research facility :envihab, is one of several studies at DLR in which the Dutch doctoral student is examining test participants and thus researching the effects on the human body and its performance.
From the laboratory to clinical research
Previously, Titiaan Post had concentrated on pharmaceutical research in the Netherlands. After a bachelor's degree at the Vrije Universiteit Amsterdam, he followed up with a master's degree at the Universiteit Leiden - and moved from research that largely relied on good lab work to research that involved studying a renal medication used for athlete doping, working with athletes. "That got me interested in clinical research with test participants," he says, explaining what led him to DLR. When he visited the :envihab research facility and its possibilities for studies, it strengthened his decision: his doctoral thesis should be done in cooperation between the Centre for Human Drug Research (Leiden), the Medical Centre of Leiden University and DLR. So he packed his suitcase, looked for a flat in Cologne and has been working at the DLR Institute of Aerospace Medicine ever since.
The ChronOx study was the first time the 32-year-old was responsible for managing a study, defining criteria for selecting the right participants, planning procedures and personnel alongside his scientific work, and now evaluating the data obtained. The study design alone was very demanding, because Post had to ensure that the test persons were not exposed to any other timers for their day-night rhythm in oxygen-reduced ambient air: Consistently low room lighting comparable to candlelight, no timers such as clocks, mobile phones or the like, no strenuous activities and moreover temporary isolation in their own room to cut off all information about the outside world.
Help with sleep deprivation and damage from heart attacks
So far, scientists have only been able to prove that a lack of oxygen has an effect on the internal clock in mice. "Research on this is still very much in its infancy," Titiaan Post emphasises. Besides mice, however, other animals still serve as models for the studies Post is conducting with healthy people: naked mole rats. The East African rodent hardly feels any pain, survives severe cancer and switches from a glucose-based to a fructose-based metabolism in the event of oxygen deficiency. With the Fructoxia study, Post is therefore investigating whether test subjects nevertheless perform well in an oxygen-reduced environment by ingesting fructose. The results of these various studies, which are being incorporated into his doctorate, could benefit patients who suffer from sleep deprivation or from damage caused by oxygen deficiency in the case of strokes or heart attacks.
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