If you live in Norway, you know how long and dark the winters can be. The lack of sunlight can affect your mood, energy, sleep and health. But did you know that there is a way to combat the winter blues with light? It's called light therapy or photobiomodulation, and it can help you reset your circadian rhythm and improve your well-being.
What is light therapy and photobiomodulation?
Light therapy is the exposure to artificial light that mimics the natural sunlight. It can be done with a special device called a light box, which emits bright white or blue light. Photobiomodulation is a type of light therapy that uses low-level laser or LED light to stimulate cellular processes and healing. Both types of light therapy can have beneficial effects on the circadian rhythm, which is the internal clock that regulates your sleep-wake cycle and other biological functions.
How does light therapy and photobiomodulation affect the circadian rhythm?
The circadian rhythm is influenced by the light-dark cycle of the environment. When your eyes perceive light, they send signals to a part of the brain called the suprachiasmatic nucleus (SCN), which is the master clock of the body. The SCN then sends signals to other organs and glands to regulate hormones, body temperature, metabolism and behavior. One of the most important hormones that the SCN controls is melatonin, which is responsible for making you feel sleepy at night and alert in the morning.
However, when the days are short and dark, as in winter, your circadian rhythm can get out of sync with the natural light-dark cycle. This can lead to symptoms such as insomnia, daytime sleepiness, depression, anxiety, fatigue, reduced immunity and impaired cognitive performance. This condition is known as seasonal affective disorder (SAD) or winter depression.
Light therapy and photobiomodulation can help you restore your circadian rhythm by providing artificial light that mimics the natural sunlight. By exposing your eyes to bright light in the morning or during the day, you can suppress your melatonin production and increase your serotonin levels, which are neurotransmitters that affect your mood and energy. By doing so, you can enhance your alertness, mood, motivation and cognitive function. You can also improve your sleep quality and duration by avoiding bright light in the evening or at night, which can stimulate your melatonin production and prepare you for sleep.
What are the benefits of light therapy and photobiomodulation on mood and depression?
Several studies have shown that light therapy and photobiomodulation can improve mood and depression in people with SAD or other forms of depression. For example, a meta-analysis of 20 randomized controlled trials found that light therapy was as effective as antidepressant medication for treating SAD . Another meta-analysis of 11 randomized controlled trials found that photobiomodulation was superior to placebo for treating major depressive disorder .
The mechanisms by which light therapy and photobiomodulation improve mood and depression are not fully understood, but they may involve several factors, such as:
- Increasing serotonin levels, which are associated with positive emotions and well-being.
- Decreasing cortisol levels, which are associated with stress and negative emotions.
- Modulating brain activity in regions involved in emotion regulation, such as the prefrontal cortex, amygdala and hippocampus.
- Enhancing neurogenesis, neuroplasticity and neuroprotection, which are processes that support brain health and function.
- Reducing inflammation, oxidative stress and mitochondrial dysfunction, which are factors that contribute to depression.
What are the benefits of light therapy and photobiomodulation on circadian health and overall health?
Besides improving mood and depression, light therapy and photobiomodulation can also have positive effects on circadian health and overall health. Circadian health refers to how well your circadian rhythm is aligned with the natural light-dark cycle and how well it regulates your biological functions. Circadian health is important for maintaining optimal physical and mental health and preventing chronic diseases.
Some of the benefits of light therapy and photobiomodulation on circadian health and overall health are:
- Improving sleep quality and duration, which are essential for restorative processes such as memory consolidation, immune function and tissue repair.
- Enhancing metabolic function, which involves glucose regulation, insulin sensitivity, appetite control and energy expenditure.
- Boosting immune function, which involves fighting infections, inflammation and cancer.
- Supporting cardiovascular function, which involves blood pressure regulation, heart rate variability and vascular health.
- Protecting cognitive function, which involves attention, memory, learning and executive function.
How to use light therapy and photobiomodulation for optimal results?
If you want to try light therapy or photobiomodulation, here are some tips to get the best results:
- Where possible expose yourself to natural light in the morning time. As early as possible and for as long as possible. Minimum during winter would be around 30 minutes.
- Alternatively, choose a light therapy device that emits bright white or blue light (I will soon have a broad spectrum light that also contains red and NIR to mimic sunlight), with an intensity of at least 10,000 lux at eye level. Choose a photobiomodulation device that emits red or near-infrared light, with a wavelength of 600-900 nm and a power density of 10-100 mW/cm2.
- Use the light therapy device for 30 minutes to an hour in the morning or during the day, preferably within two hours of waking up. Use the photobiomodulation device for 10 to 20 minutes per session, once or twice a day, depending on the area and condition you are hoping to help.
- Avoid using light therapy devices in the evening or at night, as it may interfere with your melatonin production and sleep quality. Also avoid using any other sources of bright or blue light, such as screens, lamps or LED lights, before bedtime. Instead, use dim or warm light, such as candles, incandescent bulbs or red light.
- Be consistent and patient with your light therapy or photobiomodulation treatment. It may take several days or weeks to see noticeable improvements in your mood, sleep and health.
Conclusion
Light therapy and photobiomodulation are shown to be safe and effective ways to improve your circadian rhythm through the winter darkness. By exposing yourself to morning sunlight/daylight (or at least to artificial light that mimics the natural sunlight), you can enhance your mood, energy, sleep and health. You can also help minimise the chances/severity of seasonal affective disorder and other forms of depression.
For those of use that live in Norway, or any other place with long and dark winters, you may want to give light therapy or photobiomodulation a try. You may be surprised by how much better you feel!
References
Golden RN, Gaynes BN, Ekstrom RD, Hamer RM, Jacobsen FM, Suppes T, et al. The efficacy of light therapy in the treatment of mood disorders: a review and meta-analysis of the evidence. Am J Psychiatry (2005) 162(4):656–62. doi:10.1176/appi.ajp.162.4.656
Cassano P, Petrie SR, Hamblin MR, Henderson TA, Iosifescu DV. Review of transcranial photobiomodulation for major depressive disorder: targeting brain metabolism, inflammation, oxidative stress, and neurogenesis. Neurophotonics (2016) 3(3):031404. doi:10.1117/1.NPh.3.3.031404