Tag Archives: neurotransmitters

Bright Light: Depression, Insomnia, and the sleep/wake cycle


I recently wrote an article for the Natural Medicine Journal about a study that showed the positive effects of wearing bright light glasses to treat depression. Bright light therapy has been popular for the past few decades to treat seasonal as well as non seasonal depression, but this is the first study to utilize a device that is worn like a pair of glasses and shines light down into the eyes of the wearer. In the past, subjects have used light boxes which work equally well, but the glasses have the advantage of allowing the wearer to be able to do other things during treatment.

While this study is interesting in itself, it brings up some fascinating questions about the role of light and dark, the sleep/wake cycle, and the establishment of a healthy circadian rhythm in mood regulation.

In this particular study, the participants (who were all teenagers receiving inpatient treatment for depression) were asked to complete a “Chronicity” questionnaire to establish their most productive time of day. None of the participants were found to be strongly morning people. There are many studies that have found a link between “eveningness” and depression. Additionally, insomnia (which is associated with eveningness) has been found to have an even greater impact on negative emotions.

So how does bright light impact the body to influence emotion and the circadian rhythm? In studies of bright light therapy, the light used emits 10,000 lumens, which is roughly equivalent to sunlight 40 minutes after sunrise on a clear day. When light hits the retina of the eye, the retina itself actually produces serotonin and dopamine, which help to maintain a good mood. The glasses in particular (as well as sunlight) emit blue light, which is the part of the visible light spectrum that is most stimulatory. We can surmise that if a person is spending the majority of their most wakeful hours when it is dark, it is possible that they aren’t making as much of these chemicals.

Conversely, blue light in particular suppresses retinal production of melatonin, which is one of the primary neurotransmitters responsible for sound sleep. Most of us have heard that watching screens such as the computer, TV, or phone before bed can impact sleep. This is because blue light emitted from these screens prevents the body from making melatonin which is necessary for sleep. Studies have found that people who wear blue-light blocking glasses for three hours before bed can correct insomnia and have more restful sleep.

Regardless of your light source, starting the day with exposure to healthy bright light will help you to make the chemicals you need to keep your mind feeling happy and at ease. At the end of the day, minimizing exposure to bright light and blue light in particular will help your body fall asleep more easily and have a more restful night!

Natural Approaches for Insomnia

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One of the most common problems my patients report is difficulty with sleep. Whether they have trouble getting to sleep, staying asleep, or waking frequently, not getting the rest our bodies need is frustrating and significantly impacts the severity of other ailments. Poor sleep or insufficient is linked to weight gain, cardiovascular disease, decreased immunity and poor healing. The reasons for insomnia are varied, so natural treatments need to address whatever it is that is out of balance. When thinking about insomnia, we have to make sure that three different systems are ready for sleep; the hormones, the nervous system, and the muscles. Having good bedtime habits such as stopping screen time one hour before bed, stretching, yoga, or meditation before bed, and a cup of herbal tea are all great first steps, but if sleep remains a problem, the primary places I look to regain balance are Hormones, Neurotransmitters, Blood sugar, Muscle tension, and pain. Here is how I approach this issue:
Hormones
In my practice, the most common reason I see for persistent insomnia is an imbalance in the hormones. There are several hormones that can be out of balance that will contribute to poor sleep. Often we will have to test to see which of these is the culprit:
Estrogen/Progesterone: Especially after childbirth and during menopause, when these reproductive hormones are not produced in balance with each other, sleep can be effected. Most commonly, this imbalance is accompanied by hot flashes and night sweats.
Thyroid: When thyroid function gets too low or too high it can impact the sleep. If thyroid levels are too high, often there are heart palpitations or agitation along with the insomnia. When thyroid is too low, people often will wake feeling insufficiently rested no matter how long they have slept.
Cortisol: This is our primary hormone that tells us we are awake. It is a stress hormone that helps the body to mobilize blood sugar for fight or flight situations (aka, so we can run from a bear). If we have too much stress over a prolonged period of time, though, the body will sometimes start making cortisol in the middle of the night–when this is the culprit people often will wake at 3-4am and won’t be able to go back to sleep.
Neurotransmitters
Neurotransmitters are amino-acid based chemicals produced by our nervous system that tell our brain and nerves how we feel–sleepy, awake, excited,happy, sad, etc. The three neurotransmitters that are most associated with deep, relaxing sleep are melatonin, serotonin, and GABA. GABA is derived from the amino acids glutamine or glutamate, and serotonin and melatonin are made from tryptophan. For people who are experiencing persistent or severe sleep difficulties, we can test to see what your levels are and if the more excitatory neurotransmitters are too high to allow your brain to calm down. Many of our best natural sleep aids are made from these neurotransmitters or contain precursors to them.

Blood Sugar
This category is directly related to the discussion on cortisol, above. For people who have difficulty keeping their blood sugar stable (either from hypoglycemia, metabolic syndrome, or diabetes), and especially for people who do not eat regularly, eat dinner very early, or eat sweets after dinner, this can impact sleep. For instance, if you eat dinner at 6pm, by 3am it has been 9 hours since you last ate. Although cortisol is primarily a stress hormone, its other function is to mobilize glucose from storage when the blood sugar gets too low. When cortisol spikes at 3am, then the brain wakes up and it becomes difficult to go back to sleep. In this case, a light protein snack right before bed such as an apple with peanut butter will greatly improve sleep.

Muscle tension and Pain
For people with chronic pain, it isn’t sleep itself that is the problem, but the pain that keeps them up. If there is chronic pain we have to get to the root of it and fix this issue. Often, however, there can be muscle tension that causes pain or headaches and leads to poor sleep. Tight muscles also may just keep the body so tense that sleep is difficult regardless of pain. The simplest options for helping the muscles relax before bed are stretching, deep breathing, hot baths and hydrating during the day (not so it keeps you up having to use the restroom). Other very effective options are taking some minerals such as Calcium or magnesium or drinking coconut water which is high in potassium before bed.

Insomnia can be a brief, transitory concern that is related to a specific event or a problem that can last many years. Persistent insomnia can lead to or exacerbate a host of other health concerns. By narrowing down the causes, we can individualize a plan to help put you back to sleep!