Sleep. We all need it, but are we getting enough? How much sleep do we need to function on a day to day basis without feeling fatigued or irritable? What are the side effects of sleep deprivation?

To get all the important answers we are talking to Dr Chelsie Rohrscheib.

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Donna:  Roughly speaking, we spend about one-third of our lives asleep. It’s kind of incredible and inefficient when you think about it – it's a lot of time. But sleep is a vital part of survival, just like food and water. And yet for something so important, we humans don't seem to be very good at getting enough. With busy lifestyles, longer work hours and the liquid gold of coffee, are we in fact losing sleep to the detriment of our health and productivity? To find out more about sleep, how much we need, and how to get more of it, we spoke to Dr Chelsie Rohrscheib, a postdoctoral research fellow in the Cognitive and Behavioral Lab here at the Queensland Brain Institute.

Dr. Chelsie Rohrscheib: It's pretty variable between each individual. So, we're all genetically inclined to need a specific amount of sleep and that can differ between individuals. So, some people are very short sleepers; they only need about four to six hours a night. Donald Trump recently claimed that he only sleeps about four hours a night. Other CEOs such as the CEO of Yahoo said she only got about six hours and feel perfectly refreshed after that. More typical is the seven to eight hours a night which I think the large majority of people in the population tend to need. And then there's long sleepers such as myself, who need nine or more hours a night. Again this is very dependent on your genetic make-up.

Donna: Why is it so important to get a good night sleep?

Dr. Chelsie Rohrscheib:   Well, I mean sleep is such a vital process. It affects so many different aspects of our health from our immune system to obviously our nervous system. Sleep affects all aspects of our life. It's critical for learning and memory, so when you learn over the day, you go to bed at night and your brain is able to strengthen those memories by strengthening the synaptic connections in the neurons and if we don’t get proper sleep, we're not able to accomplish that. The other thing that's really important is during the day, our brain builds up metabolic wastes and what can happen is if we get too many wastes build up, it will kind of gunk up the communication between our neurons. That's why when we're sleep deprived, it's very hard to concentrate, it's very hard to learn, it's very hard to accomplish anything. So, the brain cleanses itself at night every time we sleep.

Donna: This is perception that sleep is quite a passive process, but your research actually finds it's kind of the opposite.

Dr. Chelsie Rohrscheib: No, it's definitely not passive. We go through many different sleep stages during the night, so we start of in this very light sleep, where we're semi-conscious, but we're slowly drifting of in becoming more comfortable and as we go through the night, we fall deeper and deeper into sleep until we get into a very deep state of sleep where we're not responsive, we're not dreaming. Usually, this is the time of sleep when our brain is clearing up metabolic wastes or strengthening those synapses. We're not 100% sure what's involved in different stages of sleep, but we are trying to figure that out. And once you've gone through a deep stage of sleep, you then go into REM stage, which is typically the stage where you're going to be dreaming, so that's...your mind's actually very, very active during that stage.

Donna: So, just to clarify REM sleep meaning Rapid Eye Movement.

Dr. Chelsie Rohrscheib: Yes, rapid eye movement. And the only reason that's called rapid eye movement sleep is because your eyes tend to dart back and forth. It's not a very good way to describe that stage of sleep, but it's just something that's quite obvious when you look at somebody who's in a REM stage. So, like I said that's typically when we dream and our brain is very active. If you look at the brain waves of people during REM sleep, it looks very similar to those who are actually awake.

Donna: Do we know why we dream?

Dr. Chelsie Rohrscheib: Well, that's one of the big questions of sleep research. There's various theories. Some researchers think it's a way of replaying the activities of our day and strengthening all those connections in the neurons so that we can retain information that we've learned over the day and also get rid of information we don't need by pruning or decreasing the strength of synapses.

Donna: I want to jump back to what you were saying before about when we don't get enough sleep. I know that I'm really grumpy and I can't concentrate, but, say, if we were to take a nap in the middle of the day, does that make us less tired or does that help?

Dr. Chelsie Rohrscheib: Absolutely, napping is definitely helpful. It depends on how long your nap is. The longer you nap can be quite counterproductive. You can actually wake up groggier and worse off than you were before. However, if you nap in short bouts, so these little catnaps, as we like to call them – 20 to 30 minutes – it can be enough to refresh you and give you the new energy you need to get through the rest of your day.

Donna: Do you think as a population we're sleeping less than we used to?

Dr. Chelsie Rohrscheib: Oh, absolutely! So, there's so many pressures in Western society that we have to deal with. There's the pressure to have this work life balance, even though we're working more hours than ever before and able to accomplish this, we have to work longer, but also fit in all the activities we want to do to have that nice life balance. So, we're sleeping less to accomplish that, to fit everything in. For instance, I have a coworker – I won’t mention her name, she knows who she is – who gets up extremely early, so like 4 o'clock in the morning to go surfing every morning because she loves surfing, but she doesn’t have enough time to fit it in during the normal daytime hours. But she still manages to make it back by 8:30 or 9 o'clock every morning and do a full workday. Unfortunately, by the time she gets home, she’s absolutely exhausted and she just crashes. But unfortunately as a society, we’re definitely not getting the amount of sleep we need.

Donna: So, I imagine your coworker is probably something of a morning a person or has forced herself to be. Is there a difference between, I don't know, in genetics or is it just habit, that some people love getting up early where as other people, like me, like staying up late?

Dr. Chelsie Rohrscheib: Yup, definitely! So, there’s something called a ‘chronotype’ and this relates to our biological clocks. So, internally in our brain we have a cycle which controls all of our biological functions and that works on a 24-hour cycle. So, people range from being very early chronotypes – so those are the chirpy morning people who are extra energetic first thing, to the very late chronotypes such as myself, who only really feel energised later in the day. And this is very dependent on your genes. So, even minor changes in the genetics that regulate that cycle, can shift your chronotype.

Donna: One of the things that I’m quite conscious of now is new research that's come out about the use of blue light in mobile devices, you know laptops, phones, that can actually affect our sleep cycles. Can you tell us a little bit about that?

Dr. Chelsie Rohrscheib: So, this is one of the biggest problems when it comes to sleep at the moment is having all these devices which produce artificial light. Naturally, before we had these devices around our brains were completely wired to rely on the natural daylight, night-time cycle. So, we would wake up with the sun rising. We would go to sleep with sun setting and our internal clock would be able to follow these rhythms. Now we’re completely screwing that up because we're constantly looking at computer screens and mobile phones. We’re getting this light that imitates the sun. So, even though it might be 10 o'clock at night, when our brains are supposed to be relaxing and preparing for sleep, we're getting this massive influx of light into our system and it’s telling our brains to stay awake and we're not able to create the natural hormones which tell us to go to sleep.

Donna: What happens in places, not in Brisbane so much, but say places far north in Europe, where in summer the days are really long, but in winter the days are quite short. Do people sleep cycles change, as a result?

Dr. Chelsie Rohrscheib: Yes, they can vary. The good thing is after a long enough period of time, you will adapt to different changes in natural light. So, your biological clock will eventually become very rhythmic and you’ll still wake up and go to bed at the same time, but again using this artificial light is going to affect that regardless.

Donna: Artificial light is one of the things we know that affects sleep. Are there other factors that can change the quality of the sleep we have at night?

Dr. Chelsie Rohrscheib: Absolutely! There’s so many different things that can change the quality of your sleep. Stress is one of the biggest issues when it comes to sleep. When we’re stressed, we’re constantly on edge. Our fight-or-flight system is always prepared to, you know, keep us energised, keep us going if we need to. So, when we lay down to go to sleep at night, if all we’re doing is stressing about the day before, it’s going to be very hard for our brains to relax and go into that natural sleep cycle. Of course, other things like drugs, alcohol, caffeine will also affect sleep. Exercise is another thing. People who exercise tend to have better results with their sleep. So, if you yourself are having issues with sleep, definitely give exercise a go. It’s proven to help.

Donna: That's really interesting. Do we know why that is?

Dr. Chelsie Rohrscheib: It’s hard to say at the moment. It hasn’t been very well studied, but we think that it's related to again, coming back to stress. So, when we exercise, we reduce the levels of our stress hormone, cortisol and when that hormone is reduced it allows us to be more calm and get a better night sleep.

Donna: So, in terms of preparing to go to bed or thinking about trying to get more sleep, what are some of the easy things we can do? I mean, you’ve mentioned exercise is one of them.

Dr. Chelsie Rohrscheib: Yup, definitely. Exercise, especially cardio. Cardio tends to be the best exercise, in my personal opinion, for sleep. The other thing that will really help is staying on a very strict schedule. So, it's best if you try to wake up and go to bed at the same time every single night. If you can do that, you can train your brain to start relaxing and getting tired at a certain time at night and eventually hopefully, if you don’t have an underlining sleep disorder, you should be able to get into a rhythm where it becomes easier for you to fall asleep.

Donna: What happens if you have trouble getting to sleep are there things that you can do at night to try and prepare yourself?

Dr. Chelsie Rohrscheib: Yeah. So, ok coming back to the devices and the unnatural light: stop using your mobile phones and your computers and your TV screens at least an hour or an hour-and-a-half before you decide to go to bed. One thing I like to do is you can either meditate, so you can allow your brain to become more relaxed before sleep. You can take a warm bath. You can read; reading is great for helping you to get tired. But I think the main issue is turn off everything that’s going to distract you and also try to relax as much as possible.

Donna: Recently, in the last few years, there’s been an explosion of fitness trackers that also track sleep. Do we know whether they make any difference to people's sleep quality or whether people are getting more sleep as a result?

Dr. Chelsie Rohrscheib: I personally doubt it. I don't think they can track your sleep well enough for you to really know what's going on. Just because you're still during the night – because that's pretty much what it tracks; it tracks how still you are and your heart rate – doesn't mean you're getting good quality sleep. So, you might be in a very light sleep, where you’re not moving around and your heart rate slowed, but that doesn’t mean you’re cycling through all of the different stages properly or you’re spending enough time in each stage. So, I’d be very wary about depending on those fitness trackers to track your sleep.

Donna: Is there anything else that you’d like people to know about sleep?

Dr. Chelsie Rohrscheib: I think one of the most interesting things about sleep is it’s so dependent on our personal genetics. Everybody has such various difference in their sleep patterns and we’re starting to figure that out by looking at individual genes. I’m also personally looking at what sleep does to the genes in the brain, and, how sleep affects the body overall, which is quite interesting and I think it’s going to explode in the next few years.

Donna: That was Dr. Chelsie Rohrscheib, talking about the importance of getting a good night's sleep. That's all for this episode. I’m Donna Lu and our podcast is produced by Jessica McGaw. If you enjoyed this episode, tell your friends about it, let us know what you think on Facebook or Twitter or give us a review in iTunes, which helps other people find the podcast, too. Thanks for listening.

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