As an emergency room physician who works many different shifts at all hours of the day, I have learned a little about sleep and exhaustion over the years.
These are the sleepy categories of my life. For me there are four different kinds of tired ranging from mostly alert and ready to go, to exhausted to the point of not being any good to anybody. These are arranged from most awake to most exhausted. Converting from day shifts to night shifts puts me through the whole range.
The most awake is when I have had enough sleep and I am awake during a time that I am normally awake. A good example of this would be normal nine to fivers who sleep nights and work days. If they got a good night sleep and they are normally awake during the day, they are about as awake as you get.
Second on the scale of sleepiness is when I did not get enough sleep the night before but I am awake at a time that I am usually awake. For example a nine to fiver who did not get to bed until 2:30am. He is tired from not enough sleep, however, he is still doing his job then next day during hours that he is used to being awake.
Third sleepiest is when I slept well but I am being required to be awake during time I am not used to being awake. An example of this would be a nine to fiver who took a nap all afternoon and then had to stay up until 4am in the morning working on a presentation for work. The sleep would help, but the fact that he is usually asleep by 11pm would make him very sleepy in the middle of the am while working on his project.
The most exhausted times come when I did not get enough sleep and I am forced to stay awake during a time that I would normally be sleeping. For a nine to fiver it would be getting up at 7am, working all day and then working all night until four am on a presentation. Not only are they working at a time they should be sleeping, they have already been up all day.
For medical shift work it usually manifests itself like this. I have been working day or early evening shifts for weeks and it is time to work my first night shift. I don’t get any sleep during the day because I am not tired enough. Then I stay up all night long seeing patients. I am not used to nights and I havent been to bed in 20 hours. I am mentally and physically wiped. By day two, I have gotten a little bit of sleep before my night shift. I still stay up all night when I feel like I should be sleeping, but at least I have gotten a little sleep before my shift. Next day I sleep a little more and feel a little less like I should be asleep at four am in the morning. By my fourth shift, I sleep eight hours during the day and I feel at four am like I SHOULD be up at four am. I have succesfully converted to night schedule. Then my nights are over and it is time to switch back and go through the whole exhausting process again. All of this while making life or death decisions in a busy emergency room.
Mark Miner