Last weekend I was down about 6 hours, gained three hours in the first part of the week and was down two hours again last night. So I’ve a sleep debt of five hours.
Each weekend, I suppose I could pay four hours of sleep debt (to bed an hour early and get up an hour late– five hours if nothing fun is happening on Friday). At best, I can pay off an hour of sleep debt a day on a workday, and that only if nothing really is going on– just gym, eat, sleep and minor errands.
So 9 hours a week of sleeping in can pay back the maximum sleep debt of 20 hours in about 2 weeks, which seems low compared to other estimates of several months.
Sleep tracking in practice
I put my sleep tracker onto my Kindle Fire. Bad idea, for two reasons. I use my android cell phone for my alarm clock, so it would have made more sense to put it there. If your alarm clock is also your sleep tracking application, you can skip half of the manual entries as you only need to log when you went to sleep. The other problem is that I try turn my Kindle Fire off, which takes forever when I just want to record a data point.
Also, any manual logging of sleep start time consistently overestimate how much sleep I get since it takes time to go to sleep.
More complicated ways to calculate sleep debt.
This calculator assumes you need to sleep for 1/2 of an hour for every hour awake (I think– that’s 8 sleep per 16 awake). So to pay off sleeping only 6 hours for two nights means sleeping more than just 4 extra hours over the next few nights because you need to sleep for the extra awake hours as well. It creates an interesting algebra problem, or it means sleep debt needs to be tracked on a spreadsheet, kind of like a mortgage amortization schedule.
First point of yawning should be a good measure of sleepiness, but boredom will confound the results. In my experiment so far, I’ve started yawning at 3PM, 3PM and 11AM. And yawning is contagious, so hanging out with tired people will trigger yawning that isn’t related to sleep debt.
With Joe’s Goals you can mark up to 3 good things or 3 bad things happening on a day. That roughly corresponds to a typical increase or decrease in sleep debt– although sleep debt should only be recorded as decreasing up to 2 hours a day and only if there was a sleep debt (i.e. if you start out fully rested, you don’t get credit for sleeping in advance of the day you stay up late). I use Joe’s Goals for other goal tracking already, so this could be a good solution for sleep debt tracking.
Results. Unexplained anxiety is way down and ability to get work done is way up. That is the good news. The bad news is I’m too old to stay up late and not suffer the consequences.
Either I’m getting old, or I’m just getting better and spotting oddities in how my brain works. I’ve never been able to nap. I lack the talent for it. So if I don’t sleep, I used to sleep in to compensate. Sleeping in, it appears, isn’t happening anymore. So while trying to figure out where this disconnected sense of anxiety was coming from, it took a long time to suspect sleep debt.
The symptoms of sleep debt are either obvious– falling asleep during the day and yawning– or not so obvious– free floating anxiety. And it appears causation goes in both directions– anxiety discourages sleeping and the body pumps itself full of anxiety causing neurochemicals to keep you awake when you’re overtired, creating a vicious cycle.
Ref. Sleep debt causes anxiety:
Sleep Deprivation and Anxiety
Original research using brain imaging & experimental subjects that skipped sleeping for 35 hours.
Sleep Debt is real.
Sleeping for 6 hours a day for a 10 days will cause people to behave as if they had skipped an entire night of sleep. However at least one researcher is skeptical of the existence of sleep debt.
Curing a Sleep Debt
It takes months to fix a chronic sleep debt. Other articles on the next are less pessimistic, see below.
Measuring Sleep Debt
According to this article– sleep debt goes up to about 20 hours, can be paid off by only 2 hours a day– max. Also, if you have 0 sleep debt, you can’t sleep in today to earn the ability to stay up late tomorrow, i.e. you can’t bank excess sleep. According to this, if you sleep an extra hour a day, i.e. about 9 hours, a maximal sleep debt can be paid off in 20 days, ten if you can manage to sleep 10 hours a day.
Typically these provide for recording an entry a day, a start/stop timer, graphs and sleep debt calculations
Android Apps for Sleep Debt
Sleep Bot– I’ve got one data point in this app. Whoo!