In this podcast, Matt explores the fascinating topic of yawning. He begins by pointing out that although we all yawn and assume it's a sign of sleepiness, science hasn't provided a definitive answer regarding its purpose. Matt delves into the etymology of the word "yawn" and describes the five distinct steps involved in the yawning reflex, shedding light on its physiological process.

Matt then introduces three leading scientific theories explaining why we yawn. The first theory suggests that yawning helps cool the brain and enhances alertness by drawing in cooler air. The second theory proposes that contagious yawning synchronizes group behavior, as observed in wild animal studies. The third theory centers on regulating oxygen and carbon dioxide levels in the body, although it faces scrutiny due to research findings. Ultimately, Matt leans towards the cooling theory as the primary function of yawning.

Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way. 

Are sleep troubles keeping you up at night? Matt used to be a skeptic about meditation, but 7 years ago, he tried it using a fantastic meditation app called ‘Calm’, and it transformed his sleep! Now, he meditates for 10 minutes before bedtime every night! He’s also partnered with Calm who have been generous enough to offer his podcast listeners an exclusive 40% discount on their premium subscription! All you have to do is go to calm.com/mattwalker and take advantage of this incredible deal! Head on over now and improve your sleep today!

The good people at InsideTracker are one of the sponsors of this week's episode. For a very limited time, InsideTracker is giving you 50% off their bundles. Plus, they’re offering 30% off everything else in their store.  InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.

Another sponsor this week is the biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink that I can get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. If you want to give LMNT a try, just head on over to