Why dawn is so good for you? Why missing it is dangerous?
Waking up with the blue light of dawn is a delight for the soul. It is also a very simple, powerful discipline to save, enrich and empower your life. Over the past weeks, a surprising number of resilience participants have shared that they did not understand the concept.
For those who just want a simple, well supported practice to action now:
Wake up every morning before dawn and be outside for 30 minutes before sunrise.
For those who want a more comprehensive understanding here is my best explanation – given that much is still to be learned:
- Evolution has designed humans and almost all primates as diurnal creatures. We function best during the hours of daylight. At night we are easy prey and relatively disabled in body, emotion and mind. During the day we are safe, well and effective. Our blood pressure, brain functions, hormones, mood, metabolism and physical competence are all synchronised by the circadian clock.
- For at least 30 million years primates have woken with the dawn light. As a consequence our circadian cycle is roughly 24 hours and is paced by the effect of blue light at dawn (we call this a zeitgeber). When blue light hits the back of your eyes, you release melanopsin, which resets the suprachiasmatic nucleus (SCN). This synchronises your biology to the day, making sure you are prepared for movement, alert and engaged. Temperature, social activity, exercise and consumption are also zeitgebers.
- Securing enough sleep (between 7 and 9 hours) is important. Timing of your sleep may be more important. During the day we accumulate fatigue, sometimes measured by adenosine in the brain. This peaks as light fades, temperature drops and we become less active. Our body prepares to “flop” into sleep. This feeling of sleep pressure peaks every 90 minutes (ultradian cycle). If we drop into bed quiet, calm, cool and dark we will drop into the two important cycles of deep or NREM sleep. This is between the hours of 10pm and 2am.
- After 5 ultradian cycles (~2 deep and 3 dreaming), which equals 7.5hours, our body is ready to “flip” into wakefulness. If we have slept well – time and quality – we should wake up with a positive bias for movement and action. It is at this time that blue light is critical and the best source is at least 20 minutes for pre-dawn blue light along with movement.
- When we miss blue light we desynchronise the circadian clock. This happens in three specific situations, all of which have potential danger. The first is jetlag and the best way to reset your clock is to travel west when you can or to use melatonin at about 1mg an hour before sleep. We know that shift workers incur increased risk of cardiovascular, metabolic and cancer diseases.
- The second is weekend sleep-ins. Because most adults accumulate an hour of sleep debt per day, many try to “catch up” by sleeping in on Saturday and Sunday. This is a dangerous and foolish trap. If you miss the dawn zeitgeber over the weekend your clock with free-run for two ultradian cycles leaving your clock desynchronised. Monday mornings show a peak of heart attacks, motor vehicles accidents and suicides. See picture above.
It is also demonstrated that those who sleep in over the weekend are at much higher risk of cardio-metabolic disease – obesity, diabetes, heart disease and inflammation. The following changes when you sleep in over the weekend (Journal of Clinical Endocrinology and Metabolism, November, 2015):
- Lower HDL (know as the protective cholesterol)
- Higher Triglycerides (linked to metabolic disease)
- Higher fasting insulin and insulin resistance (diabetes and aging risk)
- Greater body mass and larger waist circumference (fat)
- The third is the desynchronisation caused by the introduction of daylight savings (DST) in spring. It is well established that there is a 10 to 24% increase in heart attacks on the Monday after DST is introduced. This is similar to the weekend sleep-in effect. The clock ‘rolls back” on us like Monday morning.
- Practical changes that deliver benefits to our clients include:
- Regular wake up time and exposure to dawn light
- Cutting the blue light from all screens for at least an hour before bed
- A cool, dark and quiet room or ear plugs and masks as needed
- Exercise earlier in the day and lighter evening meals
- A relaxation practice with slow, long exhalations before sleep
Bright Blue call to Action
Obesity is pandemic. Diabetes is epidemic. Heart disease, inflammation, health care costs, and childhood attention and learning disorders are testing our societies. Might we consider being a little biologically smarter about regular wake up with blue light and generally respecting our biological clocks? The actions are simple and free and evidence is accumulating on the positive effects for prevention, management and cure – let alone those who want to excel in life. As a parent, employer, athlete or leader this is important to test for your situation. Remember, we are all slightly different (larks and owls) so experimentation is usually necessary.
