Dr Phil Kieran: Is my teen's growth spurt to blame for his marathon sleeping? 

Dr Phil Kieran: "On average, a 15-year-old needs about nine hours of sleep per 24-hour period."

My teenage son is an Olympic sleeper. He thinks nothing of staying in bed for 14 hours during the holidays. 

I do my best to get him up and out, but he says he’s exhausted. He has no signs of illness and when he’s awake he’s in good form, but not particularly energetic. 

He’s 15 and recently had a growth spurt. Could this be the reason?

I was particularly good at sleeping in my teens. I was such a dedicated non-morning person that, in one of my jobs during my teenage years, my boss used to refer to me as ‘first-gear Phil’ whenever I worked a morning shift. 

I like to think I do a lot better now, but I know friends and family who would disagree.

For someone who is excessively tired, we need to look at their sleep habits. 

On average, a 15-year-old needs about nine hours of sleep per 24-hour period. 

This can be tricky with school, study, hobbies, sports, and all the other activities children have, which can compress their day at both ends. 

To make things worse, studies show that as we progress through adolescence, our natural patterns shift towards being more wakeful in the evening or night and less so in the mornings.

This can result in difficulty falling asleep in the evening and then having to get up early in the morning because our school or work set-up doesn’t accommodate night owls.

I would be keen to know not only what time he goes to bed, but also how quickly he falls asleep. 

If he is looking at screens late in the evening, he may take longer to reach deep sleep and therefore not get enough of it.

There is a set of habits that we can adopt to improve our sleep, collectively known as sleep hygiene. 

The website patient.info has clear information on this topic. It’s a good idea to check it and identify any areas that can be improved.

If he is mainly over-sleeping on weekends, this can suggest he is developing a sleep debt during the week and recovering some of it on weekends. 

This can be helpful, but oversleeping regularly can contribute to changes in mood and concentration. 

It would be better to try to address the sleep deficit during the week to allow him to have more enjoyable and productive weekends.

Although there isn’t a huge amount of solid research proving that growth spurts are associated with increased fatigue, it is something I frequently see in patients, and it typically resolves when the growth velocity slows a little.

If your son isn’t developing a sleep deficit during the week, I think it would be very reasonable to have some blood tests done to ensure he isn’t deficient in iron, B12, or folic acid. 

Also, to make sure his thyroid gland isn’t underactive. Chances are that this is a temporary change in sleep patterns that he will outgrow as he matures.

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