Light therapy is a popular treatment for many sleep related disorders including delayed sleep phase disorder, advanced sleep phase disorder, jet lag and oversleeping. But you don’t need a sleep disorder to benefit from light therapy. Light therapy can help you stay alert throughout the day and help you wake up naturally feeling refreshed.
What Is Bright Light Therapy
To understand the importance light has on regulating sleep, it is helpful to first understand the role of the circadian rhythm. We all have a biological clock inside our brain. It’s the job of this clock to make sure we fall asleep and stay awake at the right times. As humans, we are naturally inclined to fall asleep when it is dark and stay awake during the day. From the biological clock’s understanding of the time of the day, it regulates the body’s processes that make us either feel alert or feel sleepy.
To understand what time of the day it is, the body uses external cues, the most important of these being the amount of light entering through our eyes. Light tells our body that it is daytime and to stay awake, while a lack of light tells the body that it’s night time and time for bed. Since the only light source we encountered as early humans was the sun, light is used by our bodies to calibrate our sleep wake cycle to the day night cycle.
The most important thing to remember is that the body associates light with alertness and darkness with sleepiness.
Delayed Sleep Phase Disorder
Delayed sleep phase syndrome is when you stay up later each night and also wake up later each morning causing your sleep/wake times to shift later into the day. People with delayed sleep phase syndrome can usually only fall asleep in the early hours of the morning. Waking up early in the morning becomes increasingly difficult and can be a cause of sleep deprivation if you need to wake up for work or social commitments. It’s particularly common in teenagers and those who associate themselves as “night owls”.
If you suffer from delayed sleep phase disorder, light should be avoided at night before you go to bed. It has found that even electric light can extent the time you stay awake.
To use light therapy for delayed sleep phase disorder, get up at a reasonable time and expose yourself to light straight away. You can also use light therapy to keep you alert through the day but stop using it mid afternoon, so your alertness can begin to fall. By doing this you’ll feel more alert in the morning and less alert in the evening when it is time to fall asleep.
Advanced Sleep Phase Disorder
Advanced sleep phase syndrome is the opposite of delayed sleep phase syndrome. Instead of falling asleep and waking up late, you are early to bed and also wake up early. Around 10% of us identify ourselves as being “morning larks”, and more so as we get older.
Exposure to light during the evening can help extend the amount of time you are able stay awake and alert. This will help shift your sleep pattern forward so you can fall asleep later, and also get up later.
To stay asleep during the early hours of the morning, ensure your room is kept as dark as possible, with no light entering through the curtains.
Jet lag is where you experience problems sleeping after travelling across different time zones. This is due to the time it takes for your internal biological clock to recognize your new time zone and resynchronise your sleep wake cycle. When you go from one time zone to another, the external cues (such as light) are different. Until your circadian rhythm has adjusted, there is a conflict between your body clock’s internal time and the external time cues, causing major problems sleeping.
If you are traveling west, you will gain an hour for each time zone you cross, extending the amount of time you need to stay wake. Difficulty to do so can cause the same effects as advanced sleep phase syndrome. Make sure you get plenty of light during the evenings, and avoid light during the morning.
If you are traveling east, you will lose an hour for each time zone crossed, so you will need to fall asleep earlier and also wake up earlier. Avoid all bright light during the evening, and get as much light as possible during the day, particularly in the morning.
It can be very helpful to slowly adjust your sleep pattern at home by an hour each day before you have even stepped on the flight. The more you can do this, the easier it will be to adjust to your new time zone as fast as possible. Light therapy can be very useful to achieve this, by either introducing more light in the morning when traveling east or more light in the evening when traveling west.
Seasonal Affective Disorder & Oversleeping
Seasonal affective disorder is a type of depression caused by the lack of light in the winter months. The symptoms start around fall time and alleviate in the spring. Symptoms can include all the regular symptoms of clinical depression and also over-eating and oversleeping.
More people suffer from seasonal affective disorder the further away you move from the equator. This is because in theory we originated as a species near the equator where we were designed to receive its 12 hours of sunlight and 12 hours of darkness. The further you travel away from the equator, the less daylight you’ll receive, especially during the winter months.
But you don’t need to suffer from seasonal affective disorder to oversleep. Oversleeping was a personal problem of mine for many years, and one of this website’s most popular articles is Oversleeping and How to Stop. There are many people who have problems oversleeping all year round.
The treatment for both seasonal affective disorder and oversleeping is to introduce light into your bedroom as soon as you wake up. This has the effect of telling your body it’s daytime and to stop producing the chemicals that make you sleepy. Dawn simulators, which we’ll cover in the next section, gently increase the level of light in your room so by the time it’s time to wake up your room is fully bright.
Using light therapy as soon as you wake up will help you feel more alert and refreshed. You can also use light therapy during the day and afternoon to stay upbeat and alert.
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Where as our modern lives have somewhat taken us away from our natural sleep patterns with the introduction of shift work, artificial lights and air travel, light therapy provides a modern solution to take control of our sleep wake cycle. By using light therapy, we can help influence our circadian rhythm to sleep and stay alert at the times that are most suitable to us.