Recognizing sleepiness is difficult. We’ve established that in a young kid, but what about older students? A high schooler can get home from a swim meet, bang out a final draft of an English essay, and start studying for a government exam at midnight and may not look particularly hampered by fatigue. “As long as I get my four hours, I’m good to go” is the familiar battle cry. And sure enough, they snag two personal records at the swim meet, solid A- on the essay, and while the results of the government exam are not back yet, the feeling is that it went really well.
The ability of a child to stay up late and succeed in school is often looked upon as a positive rather than a negative, and this does not end with high school. In residency, we called it horsepower. Who cares how smart a neurology resident is when they are too tired to pull their weight during all-night hospital call? And like so many other things related to sleep, horsepower is genetic.
To understand horsepower, sleep need, and functional levels, consider these three high school students who are only getting an average of 4.5 hours of sleep/night:
If we consider Kourtney, we see that while she needs seven hours of sleep, she is only getting an average of 4.5 hours every night. She does not have the gene allowing for high function despite inadequate sleep (horsepower), so she functions poorly and struggles to stay awake in school.
Kim too is only sleeping 4.5 hours per night despite needing seven, but she was given the gift of the horsepower gene, and despite inadequate rest, she functions at a high level. The horsepower gene may be a genetic variant of HLA DQB1*0602, the gene related to narcolepsy. Individuals with this gene variant may find less sleepiness as a consequence of sleep deprivation. While this state of sleep deprivation is still an unhealthy situation for Kim, she does not display significant sleepiness. In other words, it’s totally unhealthy, but Kim can handle it!
Last, in this example we see Khloé too is only getting 4.5 hours of sleep every night, but this is in line with her natural biological need, which seems on the surface to be unusually low. She functions well despite a lower than average amount of sleep because this is what she requires . . . no need for the horsepower gene to help her perform well if her perceived deficit is not really a deficit. You may remember a name for people like Khloé. We call them short sleepers. They are those individuals who need less than normal amounts of sleep to function at their best. The genetic basis for these rare, rule-defying individuals was only recently discovered when specific gene mutations regulating sleep need were identified. Despite this, Khloé is doing well because she genetically needs less sleep.
The point of explaining all this to you is that your child is a totally unique individual with a specific array of genes that this world has never and will never see again. It is important to constantly be evaluating their sleep time and functional level. If they are getting the requisite amount of sleep and functioning well, there is little that needs to be done outside of ongoing monitoring. If your child is not getting the proper amount and is not functioning well, he may need more. As we see with Khloé, Kim, and Kourtney, for the child functioning well getting what appears to be a small amount of sleep, it may be necessary to insist upon more sleep and see if your child utilizes the sleep time (a Kim, so to speak) or seems incapable of getting this new higher amount (the rare Khloé).