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Timing Your Light, Food, & Exercise for Optimal Sleep, Energy & Mood | Dr. Samer Hattar

Episode 43 Oct 25, 2021 2h 12m 15 insights
In this episode, I host Dr. Samer Hattar, Ph.D., Chief of the Section on Light and Circadian Rhythms at the National Institute of Mental Health. Dr. Hattar is a world-renowned expert on how viewing light at particular times adjusts our mood, ability to learn, stress and hormone levels, appetite, and mental health. We discuss how to determine and use your individual light sensitivity to determine the optimal sleep-wake cycle for you. We also discuss how to combine your light viewing and waking time with the timing of your food intake and exercise in order to maximize mental and physical functioning. Dr. Hattar is credited with co-discovering the neurons in the eye that set our circadian clocks and regulate mood and appetite. He explains why even a small shift in daylight savings leads to outsized effects on our biking because of the way that our cells and circadian clocks integrate across many days. And he offers precise tools to rapidly adjust to jet lag, shift work, and reset your clock after a late night of work or socializing. This episode is filled with cutting-edge data on the biological mechanisms of human physiology and practical tools for people of all ages.  Read the full show notes for this episode at hubermanlab.com.
Actionable Insights

1. Optimize Morning Light Exposure

Expose your eyes to as much outdoor light as possible for 15-60 minutes immediately upon waking, even on cloudy days, and without sunglasses, to set your circadian clock, prime your system, and improve mood. If waking before sunrise, use a bright artificial light source until the sun is out, then transition to outdoor sunlight.

2. Minimize Evening/Night Light Exposure

Significantly dim all artificial lights in your home at night, aiming for the minimum comfortable level, and allow 10-15 minutes for your eyes to adapt to darkness. Avoid bright screens (phones, tablets) 1.5-2 hours before bed, or dim them to the lowest setting and view indirectly if necessary, as light at the wrong time can disrupt sleep and mood.

3. Embrace Daytime Bright Light

Seek abundant bright light exposure throughout the day, beyond just the morning, to satisfy a ’light hunger’ and directly enhance mood, learning, memory, and alertness, even if your circadian clock is already set.

4. Align Meal Times with Circadian Rhythm

Establish regular meal times that align with your active circadian phase and light exposure, as consistent feeding acts as a strong signal to entrain your body’s clock, regulate hunger, and support overall health. Restrict your eating window to the active phase of your circadian cycle, avoiding food intake during your body’s designated resting period.

5. Strategize Exercise Timing

Identify your optimal sleep-wake cycle and schedule exercise during your most alert period, as aligning physical activity with your natural rhythm can enhance performance and prevent sleep disruption from elevated body temperature or light exposure.

6. Utilize the Tripartite Model for Health

Adopt a holistic approach to health by considering the interplay of your circadian clock, homeostatic drives (e.g., sleep debt), and direct environmental inputs (e.g., light, stress) to optimize sleep, mood, and overall well-being.

7. Adjust to New Schedules with Light Timing

To shift your circadian clock (e.g., for travel or new routines), view bright light in the early evening to delay your clock (e.g., traveling west), or view bright light after your body’s temperature nadir (low point, typically late night/early morning) to advance your clock (e.g., traveling east). When arriving in a new time zone, avoid bright light if it’s your body’s subjective night/early morning in the new location, as this could further delay your clock instead of advancing it.

8. Evaluate Light Needs with Self-Experimentation

Do not rely solely on conscious perception for light intensity; instead, conduct simple experiments by dimming lights and allowing 10-15 minutes for eye adaptation to discover the minimum comfortable light level you truly need at night.

9. Support Foundational Nutrition

Consider taking an all-in-one vitamin, mineral, and probiotic drink (like Athletic Greens) once or twice daily to cover basic nutritional needs, address deficiencies, and support microbiome health. Supplement with Vitamin D3 K2 as it’s essential for brain/body health, cardiovascular function, and calcium regulation, as many are deficient even with sun exposure.

10. Ensure Optimal Hydration and Electrolytes

Prioritize proper hydration and adequate electrolyte intake (sodium, magnesium, potassium) for optimal brain and body function, as even slight dehydration can diminish cognitive and physical performance. Drink an electrolyte mix (like Element) first thing in the morning and during physical exercise.

11. Practice Non-Sleep Deep Rest (NSDR)

Incorporate 10-minute sessions of Yoga Nidra or Non-Sleep Deep Rest (NSDR) into your routine to significantly restore cognitive and physical energy, especially when full sleep is not possible.

12. Avoid Blue Blockers for General Use

Refrain from using blue-blocking glasses that distort the full light spectrum, as they may not effectively prevent circadian disruption if overall light intensity is high, and can negatively impact vision. Instead, adjust the spectrum of artificial lights to be warmer (less blue, more yellow) in the evening while maintaining a white appearance.

13. Minimize Light During Nighttime Awakenings

If you wake up in the middle of the night (e.g., for a bathroom break), avoid turning on bright lights or using screens to prevent sending an alerting signal to your brain, which could disrupt your ability to fall back asleep.

14. Realign After Occasional Schedule Disruptions

Do not worry excessively about occasional disruptions to your sleep-wake schedule (e.g., late nights); instead, prioritize quickly readjusting to your optimal light, eating, and exercise routine to prevent chronic misalignment.

15. Advocate Against Daylight Saving Time

Support efforts to abolish daylight saving time, as its abrupt shifts disrupt natural circadian rhythms, negatively impact health, and compound existing issues related to light exposure misalignment.