> What I've Learned. The Simple Reason You're Always Tired. 2021. YouTube, <https://www.youtube.com/watch?v=ZSdgSVyV5Jg>. # The simple reason you're always tired - In 2007, a study found that nasal delivery of Orexin-A reduced the effects of sleep deprivation in monkeys - Orexin seems to be linked with alertness - Things that increase orexin: - Exercise - Caffeine - Modafinil - Fasting - Low carb - Protein - Being lean - Weight loss - Other reasons for tiredness include: - Deficiencies in vitamins, electrolytes - Bad sleep habits - Dehydration