Podcast #4: What circadian rhythms do


  • What are circadian rhythms?
    • Biological functions that vary over a 24 hour period
      • Sleep, activity, digestion, immunity, & motivation
      • WRT to digestion, enzyme synthesis/secretion, gastric acidity, intestinal permeability, and motility are all circadian
      • At the cellular level, circadian rhythms help separate use from repair
    • Circadian rhythms help you solve the puzzle that is the environment
      • Optimizes physiology to promote success
        • Food, reproduction, etc.
      • For this to work, there need to be multiple inputs and outputs
        • We can’t simply rely on the day/night cycle
        • Need to be able to shift with food availability
      • External cues called zeitgebers help “set” your clock
        • Hormones that function to tell time include melatonin, cortisol, insulin, bile, vasopressin, ghrelin
      • Circadian rhythms help set your autonomic balance
  • Examples of how circadian rhythms work against us
    • Improper light exposure and poor sleep
    • Ghrelin and eating all of your food in the evening
    • Eating late and T2D
    • Leaky gut, disturbed bile flow
    • Adrenal dysfunction
      • Disturbed adrenal function
  • Lessons from the calorie-restricted mouse
    • CR mice live 20% longer and are time restricted feeding mice
      • FAA, eat all of their food in 3 hours, optimal light exposure
    • CR and TRE can re-establish youthful circadian gene expression in the liver
    • AL feeding causes system-wide disturbances in circadian rhythms
  • Where does this leave us?
    • Our behavior drives circadian disruption-Social jet lag
    • Circadian disruption is associated with all chronic disease
      • T2D, CVD, Neurodegenerative, IBS/IBD, arthritis, autoimmune conditions, insomnia,
    • We not only need to meet recommendations for a healthy lifestyle, we have to understand that “when matters”

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