The Science of Sleep | Dr. Sara Mednick
Dr. Sara Mednick, a cognitive neuroscientist at UC Irvine and author of "The Power of the Downstate," discusses a holistic approach to sleep, defining the "downstate" as encompassing all bodily rest. She explores practices like napping, light exposure, and sex to improve sleep and overall restoration.
Deep Dive Analysis
16 Topic Outline
Introduction to Dr. Mednick and Holistic Sleep Approach
Early Research on Napping and Memory Benefits
Nuances of Napping: Who Should and Shouldn't Nap
Defining the 'Downstate' and its Biological Basis
The Downstate's Role in Overall Health Beyond Sleep
Can Daytime Practices Compensate for Poor Sleep?
Understanding Heart Rate Variability (HRV) and its Importance
Strategies for Overcoming Sleep Anxiety and Worry
Balancing Social Life with Consistent Sleep Patterns
Optimal Timing for Exercise and Sleep
Managing Fluid Intake for Better Sleep
Leveraging Light Exposure for Circadian Rhythm
Sex and Intimacy for Improved Sleep
Recommendations for Melatonin Supplementation
Importance of Nose Breathing for Health and Sleep
The Concept of 'Resonance' in Biological Rhythms
8 Key Concepts
Downstate
A broad term encompassing all ways the body naturally relaxes and restores, including sleep, exercise recovery, and specific breathing techniques. It represents a concerted effort for restorative processes to replenish energy and nutrients used during active 'upstate' periods.
Slow Waves (in sleep)
These are the strongest indicators for the most restorative part of sleep, occurring during deepest sleep. They involve all neurons firing together (upstate) and then silencing (downstate) in one-second cycles, crucial for memory, restorative processes, growth hormone increase, cortisol decrease, and glymphatic system brain cleansing.
Glymphatic System
A system in the brain that operates during deep slow-wave sleep, where waves of liquid wash out toxins and proteins that build up across the day. If these toxins are not cleared, they can form plaques associated with dementia and Alzheimer's.
Rev (Sympathetic Nervous System)
This refers to the body's high arousal state, akin to 'fight or flight,' characterized by energetic output. It's active during waking hours and in response to stress, sending nutrient-rich blood to muscles and away from non-essential systems.
Restore (Parasympathetic Nervous System)
This is the body's 'rest and digest' system, which calms the body down after high arousal. It's responsible for bringing the system back to a relaxed state, conserving energy, and facilitating restorative processes.
Heart Rate Variability (HRV)
The variability between heartbeats, indicating the strength of your parasympathetic 'restore' system. High HRV means your body is very good at quickly speeding up and slowing down your heart rate as needed, reflecting a strong ability to calm down efficiently.
Skin Hunger
The human need for physical touch and intimacy, which activates the 'restore' system. It signals safety to the brain, helping the 'rev' system calm down and preventing the feeling of being alone.
Resonance (Biological)
An idea from physics applied to biological rhythms, suggesting that when different bodily systems (e.g., metabolic, sleep, exercise) synchronize their 'upstates' and 'downstates,' they become more powerful. This alignment allows for greater efficiency and benefit from restorative processes.
10 Questions Answered
For people with severe insomnia, napping can interfere with training the body to sleep only at night. However, for about 50% of the population who enjoy naps and don't have nighttime sleep problems, napping does not significantly impact their nighttime sleep.
While sleep is crucial for restorative processes, emerging research suggests that deep parasympathetic activity (vagal activity), which can be stimulated by practices like deep breathing or meditation, is very important for cleaning out brain toxins, a process usually associated with deep sleep. It's possible some burden could be shifted to daytime practices, but sleep remains golden.
HRV is the body's ability to calm itself down, controlled by the parasympathetic 'restore' system. When you go to sleep, there's a massive increase in HRV because sleep is a highly restorative state that activates the restore system. People who sleep well tend to have high HRV.
Get out of bed and engage in a calming activity like writing down your worries until you're tired, practicing gratitude, or reading a dense, slightly challenging book until drowsiness sets in, then immediately go to sleep.
While consistency is important for training the body's natural rhythms, occasional deviations for social enjoyment are acceptable. The body is adaptive and can adjust back to its rhythm, but fanaticism about strict schedules can be counterproductive.
Cardio that significantly 'revs you up' should be done as early in the day as possible. Strength training can be done in the afternoon. Neither should be done within approximately four hours of bedtime.
Exposing yourself to bright, natural sunlight (especially blue light spectrum) early in the morning for about 15 minutes helps jumpstart your circadian rhythm, signaling to your brain that it's daytime. In the evening, reduce blue light exposure by using filters on screens, candlelight, or yellow-filtered glasses to signal to your brain that it's time to wind down and release melatonin.
Sex stimulates the sympathetic 'rev' system, and the climax is followed by a massive 'restore' (parasympathetic) response, which can induce sleep. Additionally, the emotional intimacy and physical touch associated with sex activate the restore system, signaling safety and calming the 'guard dog rev' system.
Start with a low dose, such as one milligram, and take it one to two hours before bedtime. Melatonin is not a sleeping pill but a gentle push for your circadian rhythm to enter a sleepish state, mimicking its natural release pattern.
One can try sleeping on their side, which is more conducive to nose breathing than sleeping on the back. Another method is to use a small piece of tape over the mouth as a gentle reminder to keep the mouth closed, which can help train the body for nose breathing.
15 Actionable Insights
1. Adopt Holistic Sleep View
Think about sleep more holistically, not just as a nighttime endeavor, but as one of the body’s many ways of resting and restoring, integrating daily activities into your sleep strategy.
2. Cultivate Daytime Downstates
Intentionally engage in restorative practices during the day, such as slow deep breathing or inversion poses (legs up the wall for 10 minutes), to calm your heart and activate ‘restore’ processes.
3. Optimize Morning Light Exposure
Expose yourself to real sunlight early in the morning for at least 15 minutes, preferably outdoors, to jumpstart your circadian rhythm and signal to your brain that it’s daytime, improving sleep quality at night.
4. Control Nighttime Blue Light
Filter blue light from screens in the evening by using ’night shift’ settings, opting for candlelight, or using yellow-filtered glasses to signal to your brain that it’s time to decrease arousal and release melatonin.
5. Time Exercise Strategically
Perform cardio workouts as early in the day as possible and strength training in the afternoon, but avoid any exercise within four hours of bedtime to prevent over-stimulating your sympathetic nervous system.
6. Manage Sleep Onset Anxiety
If you can’t sleep due to worry, get out of bed and write down your concerns until you’re tired, practice gratitude by listing 10 positive things, or read a dense, slightly challenging book to ‘poop out’ your mind.
7. Prioritize Nose Breathing
Practice nose breathing throughout the day for all activities, including exercise, to become a more efficient breather, and promote nose breathing during sleep by sleeping on your side or using a gentle mouth tape.
8. Enhance Heart Rate Variability
Improve your heart rate variability (HRV) through parasympathetic practices like slow, deep breathing, meditation, yoga, or biofeedback, as high HRV indicates a strong ‘restore’ system that calms you quickly.
9. Use Sex for Sleep Onset
Time sexual activity to occur right before you want to sleep, as the intense sympathetic arousal during climax is followed by a massive ‘restore’ response, aiding in sleep onset.
10. Foster Emotional Connection
Engage in consensual physical touch, such as hugs or holding hands, and deep conversations with loved ones, as these actions activate your ‘restore’ system and increase feelings of safety, calming your ‘rev’ system.
11. Consider Melatonin Supplementation
If you have sleep onset or maintenance problems, try taking 1 milligram of melatonin one to two hours before bed, mimicking its natural release time, as studies show it’s generally safe and can gently push your circadian rhythm towards sleep.
12. Listen to Your Body’s Sleep Cues
Go to sleep the moment you feel drowsy, even if it’s earlier than your usual bedtime, as listening to your body’s natural sleepiness cues helps maintain a healthy sleep pattern.
13. Maintain Sleep Schedule Consistency
Strive for a consistent sleep pattern because your brain is a habitual machine that thrives on regularity, but allow for occasional flexibility for social events without fretting, as your body is adaptive.
14. Restrict Evening Liquids
Refrain from consuming liquids closer to bedtime, especially as you get older, to reduce the likelihood of waking up at night to urinate, which can fragment sleep.
15. Assess Napping Habits
Evaluate your napping habits: if naps make you feel refreshed and don’t disrupt nighttime sleep, they can be beneficial; however, if you nap due to accidental drowsiness or comorbidities, it may indicate underlying issues.
6 Key Quotes
A nap is as good as a night for perceptual learning.
Dr. Sarah Mednick
Sleep is golden. Sleep is a very important part of the system cleaning itself and the system making connections and memorizing and regulating our emotions, all those things.
Dr. Sarah Mednick
Fanaticism is liable to lead to some problems.
Dr. Sarah Mednick
The second you feel that sleepiness, stop whatever you're doing and go to sleep.
Dr. Sarah Mednick
Our brains, they're habitual machines, right? They're looking for consistent schedules. They're looking for ways to create habits.
Dr. Sarah Mednick
We're pack animals. So any kind of sense of being on our own, which is why the pandemic was so hard for so many people, not only did we not see people, we didn't touch people. And there's this concept of skin hunger, that after a while you actually just need to touch, you need to have some intimacy, so that your brain doesn't think that you're actually all by yourself on the planet. It's not healthy.
Dr. Sarah Mednick
3 Protocols
Protocol for Overcoming Sleep Anxiety (When in Bed Worrying)
Dr. Sarah Mednick- Get out of bed.
- Write down everything you are concerned or worrying about until you are tired and feel there's nothing else to say.
- Alternatively, practice gratitude by writing down 10 things you're grateful for to shift your mental state.
- Alternatively, read a dense, slightly challenging book (e.g., history, math, engineering) until you feel drowsy.
- The second you feel drowsy, stop what you're doing, close the book, turn off the light, and go to sleep.
Protocol for Optimizing Circadian Rhythm with Light
Dr. Sarah Mednick- In the morning, go outside and get real sunlight for at least 15 minutes (indoor light or windows are not as effective unless using a specialized all-spectrum lamp).
- In the evening, decrease blue light exposure by using filters on computer/phone screens (night shift to full yellow), using candlelight, or wearing yellow-filtered glasses.
Protocol for Nose Breathing During Sleep
Dr. Sarah Mednick- Sleep on your side, as it is generally more conducive to nose breathing than sleeping on your back.
- Consider using a small piece of tape over your mouth as a gentle reminder to keep it shut throughout the night (not to seal the mouth completely but to provide a tactile cue).
- Address any underlying sleep apnea, which can contribute to mouth breathing.