AYESHA RASCOE, HOST:
Sleep - it's the holy grail of good physical and mental health, and we all know what it feels like to not get enough of it. Or do we? Sleep researchers are finding that sleep study participants' opinion of their sleep quality differed with what the machines monitoring them reported. In other words, you might feel well rested, but your sleep data may say otherwise and vice versa. Nicole Tang is the director of the Warwick Sleep and Pain lab at the University of Warwick, and she joins us now from Coventry, England. Welcome to the program.
NICOLE TANG: Hey, hello.
RASCOE: So there seems like there's a discrepancy between the data researchers are collecting in sleep studies using objective equipment and how rested the subjects say they feel. Does this mean that a good night's sleep is, like, a subjective thing?
TANG: Well, that's a very good question. And I think you've pointed out a very interesting phenomenon these days, as lots of people are wearing a sleep tracker now when they go to sleep. And sometimes when they wake up in the morning, they will look at the watch, and the watch may give them a score - how well they have been sleeping - together with some other data - how long they have been sleeping and some other more complex indexes. Sometimes people do feel that, well, I'm not feeling quite what they said, and I would say that the way how you feel about sleep is just as important as what the watches are telling you.
RASCOE: There are also, you know, data that you get from sleep studies where people are really hooked up to very intensive machines and things of that nature. What do those machines tell you about how rested people are, and is that different from how people say they feel?
TANG: So I think what you are talking about is machines that we call polysomnography. So when you put electrodes on people's head, try to get some measurements of the electrical activity around the scope together with some other physiological measurements, like ECG to measure the heart rate - these will provide some important physiological measures.
So the way how they define sleep is quite different from the information that we, as sleeper, would use to judge the sleep. When you see sleep through the lens of technology, you are actually talking about different parameters that people use to define sleep. But when you're talking to a human, they would tell you about the experience.
RASCOE: Is there a reason why people may feel differently than what an objective measure would do? Is it because it is so personal, and we all have our kind of different rhythms?
TANG: Sleep quality may be a judgment call, and at different point of the day, you may come up with different ratings or different judgment, depending on what information that comes to your mind. When we did that experiment, we asked people to repeatedly, you know, give us rating about the sleep. And we have found out that what they do during the day would change their decision. For example, if they are in a better mood and also particularly when they have been engaged in positive physical activity, that helps them to think about their sleep better.
RASCOE: You know, according to the American Psychiatric Association, about one-third of American adults report having trouble falling asleep, staying asleep or both. From the perspective of science, what is a good night's sleep in terms of length or quality?
TANG: For scientists, we don't really have a good answer what exactly is sleep quality.
RASCOE: Do you ever have trouble sleeping? And what do you do when you have trouble sleeping?
TANG: Right. OK. So I am a human, so I do have trouble sleeping sometimes as well. There are things that you can do to help calm the mind. Breathing exercise - so what you can also do is not to try and fall asleep when your body is not ready to. So to cut out the frustration, do something boring, like reading a very boring novel, then you go back to the bed and try and sleep again.
RASCOE: Read a boring book.
(LAUGHTER)
RASCOE: I won't ask you for recommendations for that. That's Nicole Tang, director of Warwick Sleep and Pain Lab at the University of Warwick. Thank you so much for speaking with us today.
TANG: Yeah, my pleasure. Thank you. Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
