. . . but you may be getting more sleep than you think

WE LIVE in an age where everything needs to be measured, be it how many steps we take, how many Instagram followers we have — and, of course, how much sleep we get.

But I do wonder if this obsession with number of hours is helpful. If you feel tired and unrefreshed in the day, you probably are not getting enough sleep — but you don’t need a sleep tracker to tell you this.

And there is a further issue. If you are already worried about your sleep, then constantly tracking it can intensify your obsession, and thus make any sleep problem worse.

This phenomenon now has a term — ‘orthosomnia’ — where people are diagnosing themselves with sleep disorders based on their sleep tracker’s output.

On the other hand, sometimes such devices can help by proving that someone is getting more sleep than they think — although it does depend on the measurement being accurate, and this is not always the case (five different trackers are likely to give you five different verdicts).

This is a problem known as ‘sleep state misperception’ or ‘paradoxical insomnia’.

It is rare that I bring patients with insomnia into the sleep laboratory. Someone who does not sleep very well at home will definitely struggle to sleep covered in electrodes, in a strange bed.

Occasionally, though, I will admit patients for a night, and afterwards, when I ask how they slept, it is incredibly common to hear, ‘Terribly’, and that they only slept for an hour or two.

Yet their sleep study shows a very decent night’s sleep — seven or more hours, with plenty of deep sleep, which is the most restorative kind.

Clearly, something about the way the person experiences sleep is different. Perhaps it is the quality of sleep that is going wrong for these people.

Quality is something we cannot yet gauge with our technique of measuring sleep — the polysomnogram. This measures brain activity, breathing and heart rates, oxygen levels in the blood, and eye and limb movements. Or maybe it is as simple as the brain filling in time between the brief awakenings that are a feature of normal sleep. So the patient perceives wakefulness rather than the deep sleep that their brain activity suggests it is.

Either way, it illustrates that there are many factors — biological, psychological, behavioural, environmental — that all influence sleep quality as well as sleep quantity.

And for most people, sleep is a subjective experience.

TEST TO CHECK YOUR SLEEP IS NORMAL

ONE of the most frequently asked questions I hear in my sleep clinic is: ‘How much sleep is enough?’

It’s a question I do not answer — at least not with a number of hours. Indeed, I cannot answer it in that way. The question is similar to ‘What is the normal height for a ten-year-old?’

If I look at my daughter’s class photo, the children range in height hugely, but all of them are normal. Likewise, there is a range of normal sleep requirements. It depends on your genes, and the quality of your sleep.

The right amount of sleep is the number of hours needed for you to wake up feeling refreshed, not sleepy during the day, but then ready for bed at a regular time, with no difficulty dropping off.

If you are waking up before your alarm, and not needing to catch up on sleep when you have the chance at the weekend, then you are getting the right number of hours’ sleep.