Kristen Warren is the Biomedical Research Engineer at Embr Labs, as well as our very first employee. Kristen's work helped launch the first commercialized Embr Wave device, and she played a pivotal role in the design of the thermal waveforms that keep you comfortable. Nowadays, Kristen's work focuses particularly on how we can leverage temperature to improve sleep quality. We talked over Zoom to discuss her background, role at Embr, and the future of sleep technology. Tell me a little bit about your background and how you ended up working at Embr Labs I have a general engineering degree, and a master’s in biomedical engineering. My focus before Embr was on biomedical signal processing, analyzing signals such as glucose levels and pulse rates. When I was working on my Master’s thesis work I realized that the technology I was working on is used in almost every wearable device that measures heart rate. I began looking for positions working at wearable device companies as a Biomedical Engineer, translating physiological principles into engineering tools! Albeit different from monitoring, Embr is really doing exactly that -- translating the physiological principles of temperature sensations into an engineering tool that customers can utilize whenever they need to! What did your work first look like when you got here? What kinds of things were you focused on? When I first started, we were about a year from launching the product, and I was responsible for hypothesizing the ways we can generate precise, personalized, effective temperature sensations from our device and testing those hypotheses on people in order to inform the temperature profiles that we use in our device. This meant a lot of reading papers about physiology, thermoreceptors, and temperature sensation generations. From this research, we created the structure of our waveforms, and the boundaries of temperatures that we allowed users to heat and cool too! As the results of this research came to fruition, my work sort of evolved into supporting the hardware and firmware of our product, making sure that it did what I wanted it to, and could generate the sensations that I envisioned in my mind. Luckily we have people to do that now hah, so I can focus more on the research of temperature sensations and less on the implementation details! How did sleep become a part of your research/work at Embr? Sleep has always been something that we knew was linked to temperature. I still have my meeting notes from my first day and my first in-person conversation with Matt [Embr Labs co-founder and Chief Scientific Officer], and we had written down ‘Sleep studies’! We knew that the connection between temperature and things like sleep, anxiety, stress, and mood was a little more far-fetched than the link between a heating and cooling bracelet and thermal comfort. Because of that, we had to delay the sleep use case...but I’m glad we’re finally bringing it to the light! Can you talk a little more about the relationship between temperature and sleep, and how the Wave uses that relationship? Sleep, in general, is linked with temperature in a lot of intricate ways. Your sleep cycle and circadian rhythm are largely affected by your body temperature. Studies have shown that changing your peripheral skin temperature by even a small amount can result in significant changes in sleep quality. Things like taking a warm bath or shower before bed do exactly this. Lowering your core body temperature an integral part of the sleep process, and your body needs to know that if you do fall asleep and lower your core temperature, you won’t freeze in your sleep environment. Sending warmth to your extremities signals that mechanism, we have the unique ability to give people precise, personalized changes to skin temperature that affect your overall state, so it makes sense that these personalized temperature changes can also affect your sleep state! Inversely, a mechanism that has been studied far less, is the sleep quality and sleep states of populations who feel overheated while they sleep, such as menopausal women who get night-sweats. Maintaining a stable body temperature at night is also important, and cooling can help nudge the body back into a more neutral range. What do you think the future of sleep technology might look like? I find it exciting that we’re learning more and more about the sleep stages and the sleep process, the benefits of sleep from a brain and body perspective, what sleep environments are ideal, and how to use physiological principles to aid in the development of sleep technology that yields better quality sleep and therefore a better quality of life. Even now, we know that harsh light is bad for your body’s falling asleep mechanism, so devices and computers have started filtering out that light to mimic more natural conditions. I also think the most useful technology will be devices or apps that are simple and easy to use. There’s been a lot of research happening in EEG [electroencephalogram, which measures the electrical activity in the brain, which is closely related to sleep] monitoring for sleep stage detection, but no one wants to wear an uncomfortable head-worn device to sleep forevermore. Also, as technology gets smaller and more efficient, the intrusiveness of these devices can be minimized.