Prime Movers Lab Webinar Series: Decoding Sleep
A conversation with experts and entrepreneurs on the mysteries of sleep
In April, we sat down with leading researchers in the world of sleep to try and understand why we sleep and if sleep can be enhanced or augmented. The topics covered by Dr. Giulio Tononi, Dr. Keith Murphy and Dr. Tracy Jill Doty were illuminating — with some interesting theories revealed. We’ll share some of these insights from the conversation and some reminders about how to improve your own sleep quality.
Expert Panelists:
Dr. Giulio Tononi is the Director of the Center for Sleep and Consciousness at the University of Wisconsin-Madison. Dr. Tononi’s laboratory studies consciousness and its disorders as well as the mechanisms and functions of sleep.
Dr. Keith Murphy is the Head of R&D for Attune Neurosciences and a post-doctoral researcher at Stanford University. His current work explores new technologies to identify circuits bridging digestive/metabolic sensory systems with sleep in mammals.
Dr. Tracy Jill Doty is the Chief of the Sleep Research Center at the Walter Reed Army Institute of Research. Her work looks at methods to enhance alertness, decision-making, and performance in the context of degraded sleep quantity and quality across the spectrum of Army operations.
Insights
On why we sleep… ALL animals sleep. And sleep has a high opportunity cost (meaning you aren’t doing all of the other things you could be doing.) We voluntarily lose consciousness each night! So, if natural selection could have gotten rid of sleep, it would have happened by now. Sleep is still here — and so it must have a function. But there is still no “official” answer to why we sleep. Dr. Tononi suggested a theory that sleep is the “price we pay for plasticity.” Our complex and amazing brains have the ability to re-wire — which is what allows us to learn and adapt every single day. However, this plasticity comes with metabolic demands and synaptic overproduction. The brain needs a way to clear that out — and that’s one theory for the purpose of sleep. Sleep is a clearing mechanism, a core and essential function. Dr. Doty suggested that because sleep is so conserved, perhaps there is more than one singular function for sleep. And Dr. Murphy shared an emerging theory around fluid movement in the brain during sleep — the cerebrospinal fluid that bathes the brain — this fluid “flushes” the brain during sleep, clearing out the gunk. Again, a waste removal hypothesis, but more general and less related to learning specifically. This system, often called the glymphatic system, may be a key mechanism used by the brain during sleep. Either way, sleep isn’t a choice. You could choose not to eat (that would be bad of course), but you can’t choose to avoid sleep. Eventually sleep always wins.
About those slow waves…For a refresher on the stages of sleep — see our previous blog entry. Slow waves are understood to be the deepest part of sleep and potentially the most restorative. Slow waves are prioritized by the brain, especially after sleep deprivation. These slow waves may be related to the “rinsing” described above, that cleaning mechanism for the brain. Slow waves may also play a role in synaptic downscaling, that price we pay for learning. There is a lot of excitement and discussion around slow waves now — and it’s definitely one of the targets for sleep augmentation. However, it takes a while to get to slow wave sleep during the typical sleep cycle. Can you speed that up? Can you stay there longer? It turns out you CAN enhance slow waves and this work has been demonstrated with acoustic input during sleep (entrained to the slow waves) but also demonstrated with other modes of stimulation (electrical, magnetic). This may be a key to making short bouts of sleep more beneficial to the brain, or sleep more beneficial in general.
Why are current pharmaceutical sleep aids so mediocre? Sleep aids do work to shorten latency to sleep, but they only help you fall asleep faster AND unfortunately your brain adapts to them over time. So in the end, it’s a bit of a losing game. In addition, they do have some consequences — memory issues, daytime drowsiness, etc. Pharmaceutical sleep aids don’t help enhance the stages of sleep. So while you might fall asleep faster, they don’t improve the quality of your sleep overall. Is there another solution?
Sleep enhancement vs. sleep induction. I get excited by both ideas! We’ve spoken about sleep enhancement, but there is still a lot of work to be done around sleep induction. Wouldn’t it be cool if you could put on a headband for just the beginning of your night’s sleep and be guaranteed a quick trip to dreamland? I would definitely buy that. Alcohol, hypnotics and anesthesia can all put you to sleep (!!) but are not something that we should be using to get us to sleep every night. What if we want to fall asleep (and sleep well) naturally? Is there a way to entrain the brain non-invasively to enter these states? When we are trying to fall asleep, as Dr. Tononi says, we are “fighting a sea of neuromodulators” that are trying to keep the brain awake and firing. This is an emerging area where we must use science and neurophysiology to devise new mechanisms to address sleep onset.
What about those sleep headbands? There is a lot of excitement in the marketplace around headbands that measure and claim to improve sleep quality. But all headbands aren’t the same. EEG (electroencephalography) is still the gold standard for measuring sleep stages. Some headbands just record your sleep and then output metrics around sleep stages. This is useful, but limited, since it’s really hard to control your own sleep stages (especially while you are already sleeping). A better option is to have those systems be closed loop. In this case, the sleep measurement is happening in real-time through the headband, but in response to the stage you are in — for example, slow wave sleep, a variable audio tone or electrical stimulation is applied precisely during that stage to ENHANCE it. In the clinical literature, this approach has been demonstrated to enhance slow wave sleep and in some cases resulting performance. That said, everyone agreed that the current sleep headbands are still kind of clunky and not appealing for use every night. Once you have that solved, you can REALLY start to enhance sleep.
Sleep, performance and challenging conditions — Dr. Doty shared some comments about her work with the US Army. They have a big focus on recovery. In their hands, electrical stimulation, in addition to boosting slow waves, appears to have an impact on recovery, which is absolutely critical in their operational conditions. They look at situations of sleep loss, sleep deprivation and chronic sleep restriction which are common in deployed environments. They use the psychomotor vigilance test (PVT) to test performance and that measure is very sensitive to sleep deprivation. It’s a quantitative measure that allows them to assess the viability of their various interventions. In their hands, electrical stimulation during slow wave sleep appears to help return performance to baseline levels. While seemingly specific to the military, this work is actually applicable to all of us. Think about individuals who are chronically sleep deprived or on shift work. It’s really the same “operational” conditions but in the civilian world.
What can I do to improve my sleep? Oh Humans! We’re really messing with our natural sleep cycles!
- Keep caffeine intake to the morning. It’s quite amazing how long the half life of caffeine is. If you are having coffee in the afternoon, it’s actually going to be in your system well into the evening.
- Experiment with temperature. Our bodies sleep best when they are cool. Whether that’s a simple hack like lowering the temperature in your bedroom at night, or trying a cooling mattress pad, it’s definitely worth a try.
- Eliminate exposure to blue light from devices, especially at night. Phones, tablets, laptops… Blue light stimulates the brain and “tricks” it into thinking its daytime. Turn them off!
- Move your body! Even a little bit of exercise, throughout the day helps the brain and reminds it that it needs to be “cleaned out.” Data shows exercise isn’t just good for the body, it’s good for the brain!
- And — Don’t worry about it! Yes, there are a lot of devices — lots of ways to obsess about sleep. The best advice is to relax and let your body unwind naturally. Getting too worried about sleep won’t help you sleep!
These are just some highlights from the webinar, but we hope you’ll make the time to listen to the whole episode. I promise it won’t put you to sleep! Until then, stay tuned for other sleep ideas and sweet dreams!
Prime Movers Lab invests in breakthrough scientific startups founded by Prime Movers, the inventors who transform billions of lives. We invest in companies reinventing energy, transportation, infrastructure, manufacturing, human augmentation and agriculture.
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