I regularly discuss circadian rhythms with my patients. As a functional medicine dietitian, this topic is important as diet for our health and healing. If I only addressed diet and did not discuss circadian rhythms, patients will only get so far in the healing process. They will never reach their full potential with their health.
What is circadian rhythm?
It is the flow or rhythm of our body’s processes. These processes follow patterns in a 24 hour day, monthly patterns and seasonal cycles. When you honor these cycles, you can maintain a high state of health and slow down the aging process. When you go against them, you can expect poor quality of life, chronic disease and accelerated aging.
If something disrupts your circadian rhythm, you will experience:
- Poor quality sleep
- Elevated stress levels
- Weight gain and/or have difficulty losing weight
- Low energy
- Poor healing
- Disrupted gut microbiome
- Disruption of hormone production
- Faster aging
- Higher risk of diabetes
- Early death
They have proven this through research over the past few decades but many cultures have known about this for thousands of years and honor the cycles.
Sleep Effects our Circadian Rhythm
There are two tiny glands in the brain that play a major role in our circadian rhythms; the hypothalamus and the pineal gland. Light sensitive nerve cells in the retina of the eye, signal the pineal gland, telling the gland if it is day or night. Our body needs these signals to know when to synchronize different activities. When the eye senses sundown or diminishing light, it will signal the pineal gland to make melatonin. Melatonin is a hormone that gets the body ready for sleep and starts a cascade of important hormonal events that take place during the night. Melatonin also exhibits a strong antioxidant effect, lowers your body temperature while you sleep and reduces your appetite during the night; all things that create a deep, restorative sleep. Our sleep habits, aka, sleep hygiene, can affect these glands negatively and disrupt our circadian rhythms.
Block Out Light at Night
One of the biggest disruptors of our circadian rhythms is light at night. It is especially critical to avoid all blue, red & green light at night. These lights inhibit melatonin but blue light has the most detrimental effects. Avoid blue light after the sun goes down as it disrupts the signal to make melatonin. Research shows that blue light is detected even through closed eyelids. Blue light comes from screens on phones, computers and TVs . So sitting in bed at night on your phone or tablet contributes to early aging, delayed healing, weight gain, poor energy, etc.
Block out all sources of light in your bedroom including the light from an alarm clock or light from a streetlight that comes through your window. Cover your alarm clock with a t-shirt, use blackout shades on your windows and keep your phone and tablet out of the bedroom.
This is a big problem for patients that tell me they work on their computer at night after the kids go to bed. These people need to change this habit as the result will be poor health and poor quality of life.
There are products on the market that claim to block blue light such as orange-tinted glasses and covers for tablet screens but there is no evidence that these work. The problem of light remains. As long as the retina is signaling to the glands that there is still light, the circadian rhythms will not function properly.
Conversely, when the sun comes up in the morning, these same nerve cells in the eye’s retina tell your glands it’s time to wake up. Your body will then be signaled to release cortisol, the hormone that wakes us up and makes us feel energized. The best thing you can do for cortisol production in the morning is to get sun exposure. So grab your coffee or tea and sit outside in the morning sun before you start your day and you will reap the benefits all day long. This is also the time you can be on your phone or tablet causing no hormonal disturbances.
If your day begins before the sun comes up there are alarm clocks that mimic the sunrise. The light slowly gets brighter over time, usually over a 30-minute time frame until it fills your bedroom with bright yellow light. Some brands have clinical studies that show the benefits. One such brand is Philips Wake-Up Light http://mb.cision.com/Public/MigratedWpy/81617/9077638/80ece083943f51dd.pdf I have no financial or other connections to this brand, I just like the fact they have conducted clinical trials on their product.
Timing of Meals
Our circadian rhythms also dictate the timing of our meals. Our digestive system is the strongest between 10:00 am – 2:00pm so this is when we would want to have our largest meal of the day. Most countries around the world do this. Our digestive system then slows down in the evening and shuts down at 7:00pm. Therefore, dinner should be a light meal. This is also why it is very important to stop eating after 7:00pm. At 7:00pm our bodies processes focus on getting ready for sleep. If you eat after 7:00pm the body has to stop the sleep cycle hormones and now focus on digestion. This is the exact reason we don’t sleep well if we eat late.
When the sleep cycle hormones get disrupted by having to digest food, you also miss out on producing human growth hormone (HGH). We release HGH after the onset of deep sleep. In adults, this hormone helps maintain muscle & bone, breaks down fat, keeps our skin tight and help maintain adequate energy levels. HGH does many positive things for our body but the most significant thing it does for us is, preserves the length of our telomeres. Without getting too technical, long telomeres keep us young, short telomeres accelerate aging. When you don’t produce HGH, your telomeres will shorten accelerating your aging.
If you make an effort to honor your circadian rhythms by eating before 7:00pm, avoiding screens in the evening, keeping your bedroom dark you will see a significant difference in the quality of your sleep and you will wake more refreshed. You will see a difference in your mood, a sustained increase in energy and a noticeable improvement in your appearance, especially your skin. Those are the benefits you and others will notice about you but internally, huge strides are being made in the health and healing of tissues. It won’t take you long to see the results. Even after the first few nights, you will see the difference and that will motivate you enough to keep you going.
Karen Graham, RDN – Functional Medicine Dietitian