1 The normal value for the partial pressure of arterial oxygen (PaO2) irrespective of age is greater than 80 mmHg/10.6 kPa (Mellengard K, 1966, Sorbini CA et al, 1968).2  The normal PaO2 for a given age can be predicted from: -. The normal value for the partial pressure of arterial oxygen (PaO2) irrespective of age is greater than 80 mmHg/10.6 kPa (Mellengard K, 1966, Sorbini CA et al, 1968).
When to take: Depending on the severity of the sleep problem, take time-released melatonin 1 to 3 hours prior to the time you usually fall asleep. Since time release melatonin only lasts for 3 â 4 hours, any need to shift sleep schedules more than 3 hours may require taking another pill in 3 or 4 hours. Cautions: Melatonin should not be taken if eyes are exposed to bright sunlight, and melatonin should be avoided if operating any vehicle. If attempting sleep shifts of more than 1 hour, light therapy should also be used. Do not use melatonin for more than two weeks at a time.
3 Things That Could Help You Sleep Better. Stop using all technology 30 min before bed- no cell phone- no lap top- no kindle. The light block melatonin which can help you fall asleep. A 30 min wind down with relaxation and reading (a paper book) can make it easier to fall asleep.