Ernest Hemingway once said “I love sleep. My life has the tendency to fall apart when I’m awake.” It’s a sentiment many can sympathize with, but for some, sleep is challenging in itself. They can’t fall asleep when they want to and they wake up too early or too late. Because they don’t get enough sleep, they spend the next day weary and unable to concentrate. Poor sleep also exacerbates mood disorders such as depression and anxiety.
Light therapy, sometimes called phototherapy, is a natural, non-pharmacological treatment that alleviates sleep problems by aligning the body’s instinctive sleep pattern with our preferred sleep and wake times.
What Is Light Therapy?
Human sleep patterns are primarily shaped by the circadian rhythm. This “internal clock” tells our body when to prepare for sleep and when it’s time to wake up. Before bed, it prompts the release of the sleep hormone melatonin, which kicks off various winding-down processes. In the morning, it controls the release of neurotransmitters that make us more alert and ready for activity.
A number of environmental and behavioral factors influence the circadian rhythm, but light exposure has the biggest impact. Over millions of years, our bodies evolved to expect rest when the sun sets in the evening and activity when it rises in the morning. Light therapy takes advantage of this light sensitivity to “reset” our internal clock and help us to wake up and fall asleep at more convenient times.
The most common form of light therapy uses timed exposures to bright full-spectrum light at specific times depending on the nature of the disorder. It is possible to use natural light, but bright light therapy typically uses artificial light from a bright lamp called a lightbox or a light-emitting visor. Light therapy treatment may also limit light exposure at certain times using sunglasses or blackout goggles.
Light Therapy and Delayed Sleep Phase Syndrome
Delayed Sleep Phase Syndrome (DSPS) is a circadian disorder that shifts the sleep period later than is desirable. People with DSPS struggle to fall asleep when they go to bed. They may want to go to bed at 10 pm, but they don’t fall asleep until midnight or later. Because everyone needs seven or eight hours of sleep, DSPS leaves people underslept or forces them to get up much later than they would like.
You can think of DSPS as “night-owl syndrome”. People go to bed and wake up later in the day. They feel at their most alert and productive later than is usual in a standard Western work and relaxation schedule.
Light therapy treatments for DSPS attempt to move the circadian rhythm back in time. It does this by exposing them to bright light when they first wake up in the morning. A treatment course might involve getting up at the desired time and using a lightbox to provide 90 minutes of bright light exposure. In some cases, patients will also be asked to reduce light exposure in the evenings.
Over time, the circadian rhythm adapts its hormone and neurotransmitter releases earlier in the evening and morning.
Light Therapy and Advanced Sleep Phase Syndrome
Advanced Sleep Phase Syndrome (ASPS) is DSPS’s mirror. Sufferers begin to feel tired earlier in the evening than usual. They often begin to get sleepy around 7 pm and struggle to stay awake until bedtime. As you might expect, they also wake up earlier than they would like. As with DSPS, trying to fit a standard workday into the schedule of an ASPS circadian rhythm leaves sufferers exhausted because they stay up later than their body expects and wake up earlier than they want.
Light therapy for ASPS involves bright light exposure in the evening. The goal is to delay the production of melatonin and push sleep times later in the evening.
Circadian Sleep Disorders vs. Insomnia
It’s important to distinguish between circadian rhythm disorders and insomnia. They are different even though they may look the same from the perspective of some sufferers. People with circadian disorders don’t have trouble getting enough good quality sleep if their sleep schedule aligns with their body clock. However, because their circadian rhythm is misaligned, shortened, or lengthened relative to the average population, they may not want to sleep when their body tells them they should.
In contrast, insomnia sufferers struggle to fall asleep and to get good quality sleep regardless of when they go to bed. Insomnia has many different causes, from mood disorders to chronic pain to medication to an uncomfortable sleep environment. Light therapy is less useful in these cases, and insomnia sufferers should seek medical advice if they have trouble sleeping for longer than a few weeks.
Bright light therapy has proven an excellent natural method for tackling one class of sleep problems. It’s inexpensive, effective, and drug-free. It’s worth trying if you have trouble getting to sleep and waking up when you want.