How do people react to hypoxic exposure equivalent to 17,000 feet (5200m)? Is it comfortable to sit and read or is it unpleasant?

The important thing to remember is that with IHT you are not exposed to high simulated altitudes for prolonged periods, each hypoxic interval would typically be no longer than 7 minutes. During the hypoxic exposure you will have a minor increase in heart rate and breathing (ventilation). There is no impairment to cognitive abilities with short term exposure to these altitudes and the user typically does not experience any unpleasant sensations if the standard protocols are adhered to. On the contrary, the process is relaxing and has a calming effect on almost everyone.