Ask An Expert: Cassie Hilditch Wants You to Sleep
Cassie Hilditch, senior research associate with the SJSU Research Foundation based at NASA Ames Research Center, is a sleep scientist whose primary research focus is fatigue risk management. Photo courtesy of Cassie Hilditch.
Cassie Hilditch, senior research associate with the SJSU Research Foundation based at NASA Ames Research Center, wants people to know one thing about sleep: it’s amazing. Her primary research focus as a sleep scientist is fatigue risk management; she consults with and studies commercial aviation pilots and other shift workers to discover how fatigue affects performance.
But her fascination with sleep runs deeper: She fell in love with sleep science as an undergraduate, during a random placement in a sleep lab, and the rest was history. Through her work she’s earned several awards, including the NASA Exceptional Public Achievement Medal, but her love of applied science is what drives her. “I can talk to anyone at a bar about what I do because it affects everyone,” she says. “Everyone has a story about their own sleep.”
As finals approach and the days get shorter, we reached out to Hilditch for tips on how to sleep better, the importance of naps and more.
What’s one thing you wish people knew about sleep?
Cassie Hilditch (CH): How important it is. A lot of people focus on what they eat and how much they exercise, but sleep is really as important as those other factors. We call it the “third pillar of health,” but it’s lagged behind in public awareness. In schools we teach people how to eat healthy and that they need to exercise. But up until this point, at least, there’s been less information about how to get healthy sleep.
What’s one of your most important tips for getting better sleep?
CH: Sleep researchers are now learning more about how important the timing and regularity of your sleep is, in addition to the duration of it. I think if you asked most people how much sleep you’re supposed to have, they would say something around the eight hour mark, and that’s close to the recommended seven to nine hours.
But very few people know how important timing and regularity is. Having a pretty regular bedtime and waking time is really important to support the quality of your sleep and to get the benefits of being alert and healthy during your waking hours.
You study how sleep can affect focus and performance. With finals coming up, what would you tell students if they’re thinking of pulling an all-nighter? Is it worth it for their memory to maybe get more sleep than they think they need?
CH: There’s the temptation to pull that all-nighter to study or get an assignment done, but sleep itself is really important for memory and learning. If you’re cramming but not sleeping, then a lot of that [studying] time is wasted because you’re not getting the sleep to really consolidate what you’ve just tried to cram in.
Students should try to study or do assignments when they’d normally be awake and are functioning at their best. Try to protect your sleep time so you’re getting the most out of the hours that you are studying. You’re going to get the benefits of studying if you’re protecting your sleep as well.
Also, there are some studies that show that taking a nap after a learning session can help boost your recall. So if you’ve found that you did stay up later than you intended, then having a nap to supplement that lost sleep might be a good idea.
Just be careful that even if you’re stressed, you’re not drinking too much caffeine too late such that it’s interrupting or delaying your sleep. And alcohol can disrupt the quality of your sleep as well. So trying to avoid those kinds of substances when you’re trying to maximize your sleep can help, too.
How do you feel about daylight saving time? Is there research into how that affects sleep?
CH: Yes. Most of the sleep research communities around the world have put out position statements on daylight saving. The consensus is that permanent standard time is better and we should do away with the switches of going back and forth. With daylight saving time, the extra light in the evening delays our sleep and is worse for the alignment of sleep with our daily activities. I know that people associate daylight saving time with beautiful summer evenings, but you’d still have longer days in summer even if you didn’t shift the clocks.
There are a lot of products on the market now that track sleep. How do you feel about them and what has research proven about their effectiveness?
CH: The increase in all these kinds of wearables has been really interesting. The positives are that people are more aware of their sleep and that can lead to better sleep habits. For example, because of the step counter on my phone, I now make sure that I get my steps.
But just like the step count on your phone isn’t necessarily exactly accurate about how many steps you took, your sleep app might not be exactly accurate about how much sleep you had. Looking at it in terms of your own progress is probably the best way to look at it, rather than fixating on a number.
Most products out there at the moment that claim to give you information about the staging of your sleep – whether it’s light, or deep, or REM sleep (rapid eye movement sleep, when most dreams occur) – [aren’t very accurate]. Most of the studies of the products that are available to date have shown that the products are only about as good as a coin toss on predicting the actual staging. They’re pretty good at tracking the duration of your sleep, though.
The potential negative to sleep tracking is that people become really fixated on it and worry about their sleep, because that anxiety can affect your sleep and turn into a negative cycle. The products are giving you some information that you can use to gauge how well you did that night, but not necessarily an exact, accurate reflection of your sleep. And if you feel like you’re having sleep problems, you should go to your doctor.
What suggestions do you have for less serious sleep problems, like run-of-the-mill insomnia?
CH: If you’re having trouble sleeping, think about not having caffeine or alcohol within about five hours of when you want to sleep. And if you’re having trouble falling asleep, that might be connected to certain behaviors. We’re all scrolling through our phones and whatnot late into the night, and there’s been a lot of talk about the exposure to blue light from our screens and how that affects sleep.
The more we look into it, it’s a combination of light exposure, but also it’s about what you’re doing. If you’re playing an active shooter game or something that gets you really amped up, then you’re not going to fall asleep straight after.
It’s also about the displacement of the activity itself. I know I’m guilty of this. I get into bed at 11, planning to go to bed at 11. And I think, I’ll just do one last scroll of the apps. And then suddenly it’s 11:30. So you’re replacing your sleep time with something on your phone that might be giving you light exposure and is also delaying your sleep. Try to be aware of those pre-sleep routines and try not to get into bad habits there.
If you’re awake in the middle of the night, what is the best way to go back to sleep?
CH: If you’re just lying in bed tossing and turning for around 20 minutes or so, the advice is to get out of bed. Obviously everyone’s home situation is different, but if you can go sit in another room on a nice comfy couch in dim lighting and just read a book or do something relaxing, that can help. And then once you’re feeling sleepy again, you should return to the bed to try to sleep. The idea is that you don’t want to associate your bed with not being able to sleep; you don’t want to spend too much time having that feeling in your bed.
To be clear, I’m not a medical doctor. So if something’s happening regularly and simple behavioral changes aren’t helping, then certainly see your doctor about it because it could be something physical or psychological. A lot of anxiety can disrupt your sleep. And I think we’re all pretty stressed right now.
In your research, what was the most surprising thing you learned about sleep?
CH: I think the scale of the number of people who are sleep deprived in our communities is one of the most surprising things. Large-scale surveys (e.g., the National Sleep Foundation’s Sleep in America Poll) show that on average, people are not getting the minimum of seven hours of sleep per night.
It’s not necessarily these extreme examples like shift workers who might have disrupted sleep. It’s this chronic sleep restriction where a lot of people are getting six and a half hours of sleep per night, which means that over time they’re just not quite recharging their batteries over and over and over again.
That can cumulatively lead to performance impairments that you would otherwise see only if someone had a really extreme sleep loss situation. And we’re not necessarily very good judges of our own alertness in those chronic sleep restriction situations. If we’re kept awake for a whole night, we’re pretty good about knowing that we feel terrible. But if you restrict someone’s sleep just a little bit over one to two weeks, you see that their performance continues to get worse over that time, but their rating of their alertness eventually plateaus. It becomes this disconnect where people think that they have adapted to this lower level of sleep, but their actual performance is still not at their best.
Is there anything else you think readers should know about sleep?
CH: I guess I always fall into the trap of talking about the negative consequences of sleep loss. But the more important messaging is about the positive outcomes of good sleep.
There’s research showing that if you sleep well, then the benefits of the exercise you did that day are actually greater. You improve your memory. You improve your learning. Sleeping well improves our mood. And being in a better mood means better communication, better relationships. Better sleep also means better cognitive performance; you can be more switched on. And if you’re into sports, you can have faster reaction times.
Think about sleep as this amazing tool that can make us feel better. It’s pretty amazing that you can close your eyes and your brain does all this work sort of offline, to get you at your best the next day.
