Every human, animal, insect, and even (we think) plant does something that looks like sleep. Obviously, this is a pivotal function, but what is it for? It might surprise you to know that a lot of what we know about sleep is still theoretical
We all know the quality and quantity of sleep deeply affect how you feel, how much energy you have, how much emotional tolerance (or how little), and even your metabolic state. Research is showing that REM sleep is most critical for brain performance and memory formation, but the combination of REM and deep sleep are what help you feel rested.
Why Do You Sleep
Sleep is something that research is only beginning to understand, but both the research and our intuitive sense of ourselves say the same thing. Sleep is when we heal, repair damage, tidy the house of our physical body, and when our brain has the time to sort and process the events and interactions of the day. Sleep is when a lot of our own physical maintenance happens, including repair, regeneration, and detoxification.
Phases of Sleep
During sleep, you cycle through the two major phases of sleep: rapid eye movement, or REM, and non-REM sleep. Each cycle takes between 80 and 100 minutes, and most people experience four to six sleep cycles per night. Many people wake more easily between these sleep cycles.
The rapid eye movement phase of sleep is named after its most characteristic feature, and during this sleep phase your brain shows similar levels of activity to those you experience during your waking hours. Dreaming usually happens during REM, although it can happen in other sleep stages too, and in normal sleep your muscles become limp to protect you from acting out your dreams. REM sleep levels are usually higher in later parts of the night, and lower in cold temperatures because during REM your body temperature is poorly regulated. Newborns spend more time in REM sleep relative to adults, and the amount may decline with age.
REM sleep is associated with the consolidation of memories, helping your body keep what is useful and discard what isn’t necessary. This includes new learnings as well as motor skills. REM sleep is also thought to be involved with emotional processing and brain development. Your amygdala, the area of your brain that is most involved with emotions, is activated in REM sleep.
Stage I – Light Sleep
This is the first, drifty phase of sleep in which your brain and breathing both slow down, and your body becomes more relaxed but still retains some muscle tone. The brain waves you see in this phase of sleep are called low-amplitude mixed-frequency waves, and they take over from the alpha waves that predominated during the drowsy period.
Stage II – Light Sleep
This stage is also light sleep, but becoming deeper as heart rate and body temperature both decrease. This phase is like a transition to deeper sleep and brain activity is characterized by specific brain wave patterns called sleep spindles and K-complexes.
Stage III – Deep Sleep
This phase is characterized by deep, slow brain waves called delta waves. Waking from this sleep phase is extremely difficult and feels like dragging yourself out of deep water, a feeling called sleep inertia. In deep sleep, your body works on physical repairs, including bone, muscle, connective tissue, and immune system activities.
MTHFR, Methylation, and Sleep
Research on the associations between MTHFR and sleep has yet to be there – literally, not one study has been published, but sleep difficulties are among the top self-reported symptoms with MTHFR. One interesting case report was published in the Journal of Clinical Sleep Medicine following a patient with chronic insomnia who was resistant to both conventional medications for sleep and cognitive behavioral therapy for insomnia. Routine lab work showed high homocysteine, which caused the physician to order gene testing. No surprise, a homozygous C677T mutation was found. In this case, targeting the MTHFR polymorphism with methylcobalamin and folate resolved the sleep issue, which is promising for MTHFR mutants.
Sleep and Circadian Rhythms
Circadian rhythms are 24-hour cycles that run all the time in the background to help your body run functions and processes at the optimal time of day. The sleep-wake cycle is one of the most essential circadian rhythms. Like many others, it is determined by a biological clock within your brain that is directly influenced by environmental cues, especially light. Other factors in your environment can affect your circadian rhythm as well, including exercise, social activity, and temperature, but light has the strongest influence on basic physiological timing.
The darkness of the setting sun is the primary signal to your biological clock to begin production of melatonin, your primary sleep hormone. Remember that if you spend your evening staring into the mini-sun of a computer or TV screen, this action is stunted. Even with blue-light blocking glasses or screen protectors, the amount of regular old light through the rest of the spectrum is enough to do harm to this process. Also, the rays of the rising sun help to trigger cortisol release and boost neurotransmitters that get you up and moving for the day.
Circadian rhythms promote consistent and restorative sleep when properly aligned to your environment. When misaligned, your circadian rhythm can promote insomnia and sleep dysfunction. One of the easiest ways to tell if your circadian rhythm is aligned properly is if you notice that you begin to feel sleepy when the sun is setting.
8 Tips for A Healthier Sleep-Wake Cycle
Maintaining a healthy sleep-wake cycle comes down to setting a normal routine for yourself through the day that optimizes your activity with your biological clock.
- Maintain a regular sleep schedule. Try to wake up and fall asleep at roughly the same time every day.
- Sun-worship. Get exposure to sun as early in the day as you can. If that is too difficult in your life, consider investing in a full-spectrum therapy 10,000 lux therapy lamp (affiliate link – if you choose to use it, thanks for supporting what we do here!) to use for 15 minutes at the start of every day. This type of light has been shown to increase sleep quality and also improve depression.
- Physical activity. Exercising or having a physically active day constantly improves sleep quality and helps to maintain a healthy sleep-wake cycle.
- Avoid caffeine after noon. Caffeine after noon has been shown to disrupt sleep cycle for most genotypes. The exception is CYP 1A2 fast caffeine metabolizers, who can handle higher levels of caffeine, possibly later in the day (studies tentatively say before 3-4:00 pm.)
- Low lights before bedtime. Completely outside of romantic potential for this habit, low lights and no screens for the two hours before your bedtime help to ensure a healthy sleep-wake cycle and go a long way to counteract the constant staring into a computer or TV screen that most of us engage in. Why not try candlelight and soft lamps for the last two hours?
- Short, early naps. Napping has been shown time and time again to be amazing for your health and mental performance, but in terms of your sleep-wake cycle, the best naps are early afternoon, and shorter than 90 minutes.
- Make a sleep Zone. Your bedroom is your sleep zone, and making sure you have a comfortable mattress, appropriate bedding, and a calm, peaceful environment will help you maximize sleep time.
- Consistent low-carb dinner. Dinner should be a light, balanced meal, eaten at least an hour or two before bed. When looking down at your plate, divide it into healthy quarters. 1/4 of the plate should be a protein like meat, eggs, fish, beans, or quinoa. 1/2 of the plate should be vegetables, not including starchy vegetables like corn or potatoes, and the remaining 1/4 can be starch like rice, corn, potatoes, bread, or other grains. If you want something sweet, make sure it is small and eaten right after dinner (not the giant impulse bowl of ice cream right before bed). Maintaining a healthy blood sugar overnight will help to keep your body in deeper sleep.
Thanks for watching or listening this week – I would appreciate it if you would leave a review, hopefully positive, on your favorite podcast platform. Next episode, we’ll talk about the four big categories of sleep problems.
MTHFR is a common genetic mutation that can contribute to anxiety, depression, fatigue, chronic pain, infertility, and more serious conditions like breast implant illness, heart attack, stroke, chronic fatigue syndrome, and some types of cancer. If you know or suspect you have an MTHFR variant, schedule a free 15-minute meet-and-greet appointment with MTHFR expert Dr. Amy today.Book Your Appointment