If you’re like me, you may have a case of email apnea, where you stop taking restful breaths when you open a work email. Or maybe you’re in the habit of shining blue light into your eyes long after sunset through your phone. Many of us are doing all kinds of things throughout the day that put us in a constant state of fight or flight arousal, with long-term impacts on health, productivity and happiness.My guest for today’s episode is Sara Mednick, author of The Power of the Downstate, a book about the art and science of rest and relaxation – why it’s so important, the best ways to go about getting more of it, and the time of day when our bodies are biologically suited to get the most benefits from it. As a cognitive neuroscientist at the University of California, Irvine, Mednick has a great scientific background on this topic. Read her bio here. Show notes3:10 – The definition of “upstates” and “downstates”                              5:50 – The power of 6 slow, deep breaths per minute to balance the nervous system9:05 – Watching out for mouth breathing and email apnea13:30 – Different ways of breathing for different goals16:35 – Body rhythms – what is heart rate variability and why is it so important?21:05 – Are you naturally a morning or night person? Nature vs nurture  27:10 – The perfect storm that gets in the way of following our circadian rhythms29:15 – The evolution of our pre-bedtime downstates – why it's important to check in with your cave mates 30:10 – The culture shift needed for more people to follow their circadian rhythms and improve their health35:10 – Employers and communities can build downstates into daily work and life38:15 – Choosing how we react to the world 41:00 – Being smarter about peak performance 45:09 – The science of pacing yourself for long-term productivity49:42 – The science of light exposure for circadian rhythms 52:20 – Where to learn more about Sara Mednick’s research and writingLinks:Sara Mednick’s website https://www.saramednick.com/  and her Twitter Mednick’s recent book - The Power of the Downstate Mednick’s book on the benefits of napping - Take a Nap! Change Your LifeThe blue light blocking glasses recommended in Mednick’s book https://www.amazon.com/dp/B019C3O2UE?psc=1&ref=ppx_yo2ov_dt_b_product_details An app for measuring heart rate variability - Elite HRV app  https://elitehrv.com/ Thorne take-home Melatonin test