Light Therapy For Jet Lag

Have you ever experienced jet lag? If so, do you remember that feeling of tiredness and fatigue during the daytime but an inability to sleep at night, and wishing for a quicker way to adjust to a new time zone? Look no further - light therapy could be your solution. 

Read on to discover how something as simple as light can help you overcome your jet lag symptoms and make your travels more enjoyable, including how light therapy works, how to implement it for the most effective results, and the benefits and potential risks of light therapy.

What is jet lag?

Jet lag is a temporary sleep disorder that occurs when your normal sleep pattern is disturbed by rapid travel across multiple time zones. This occurs because your body’s internal clock (called your circadian rhythm) is out of sync with the time zone you are currently in and is instead still synced with your original time zone. For example, if you leave London on a flight at 2 p.m. and arrive 8 hours later in New York, your internal body clock would think it is 10 p.m. and would be preparing you to go to sleep, but the local time in New York would only be 5 p.m. 

Your circadian rhythm signals to your body when to wake up and when to go to sleep. Therefore, if your body thinks you are in a different time zone than the one you are in, this can lead to you feeling tired during the daytime or having trouble falling asleep at night. It can take a few days for your body to adjust to the new time zone, and during this time you will experience jet lag.¹

What are the symptoms of jet lag?

Jet lag can cause a range of symptoms, including:

• Disrupted sleep patterns
• Daytime fatigue and tiredness
• General unwell feeling
• Difficulty concentrating and staying alert
• Irritability and mood changes
• Gastrointestinal discomfort (e.g., constipation or diarrhoea)

These symptoms are temporary and usually resolve within several days after travelling. However, symptoms are likely to be worse or last longer the further you travel and can affect your comfort while away.

TIP: As a general rule, for each time zone you cross you should expect to take another day to recover from jet lag. 

What is light therapy?

Light therapy, also known as phototherapy or bright light therapy, involves exposure to an artificial light that emits a bright light similar to natural sunlight. Light therapy aims to regulate your internal body clock and alleviate some of the symptoms associated with various conditions and sleep disorders, including jet lag.

How does light therapy work?

The underlying principle of how light therapy works is based on how your body naturally responds to light. Particularly, the light’s impact on the secretion of melatonin - an essential hormone that regulates sleep-wake cycles. 

Your melatonin levels fluctuate in a daily cycle, with higher levels at night promoting drowsiness and low levels during the day to keep you awake. This promotes a stable sleep-wake schedule and normalises your body’s circadian rhythm. Melatonin is naturally produced by your body in the dark while light exposure can slow or halt its production, therefore light therapy can be used to adjust your melatonin cycles and hence your sleep-wake schedule.²

What does light therapy involve?

During light therapy, you sit in front of a device designed for light therapy for a set amount of time each day. Light therapy devices emit bright light at specific wavelengths (typically 460-525 nm) and intensities (typically 2,000-10,000 lux), which mimic natural sunlight and are effective at regulating circadian rhythms. These devices can include:

• Light therapy box or lamp
• Light therapy visor
• Light therapy glasses

These light therapy devices are designed to shine the light indirectly into your eyes and filter out harmful ultraviolet (UV) rays. It is important to use a device specifically designed for light therapy to treat sleep disorders instead of alternative light devices (e.g., to treat skin disorders). 

How can light therapy be used for jet lag?

Light therapy for jet lag involves strategic exposure to bright light to help reset your body’s internal clock and facilitate adjustment to new time zones. Research has shown that timed exposure to bright light can effectively reduce the severity and duration of jet lag symptoms, allowing travellers to adapt more quickly to their new environment.^3,4,5

It is thought that light therapy is effective for jet lag because your internal body clock is strongly influenced by sunlight through the regulation of melatonin. Since melatonin is produced by your body in the dark and promotes sleepiness, it regulates your sleep-wake cycles. If you are unable to have exposure to natural sunlight during your travels, light therapy can be an effective alternative solution.

By initiating light therapy sessions shortly after waking up, the light will signal to your body to suppress melatonin production, therefore helping to signal the start of the day to your body and promote alertness and wakefulness. Similarly, you should minimise your exposure to light in the evening to allow melatonin levels to rise, signalling the onset of sleep and facilitating restful sleep at night.³

It is important to consult with your healthcare provider before starting light therapy if you have any pre-existing medical conditions or are taking any prescribed medications to ensure that light therapy is safe and appropriate for you.

How to implement light therapy for jet lag?

Timing of light exposure

The timing of light exposure is an essential factor that determines how effective light therapy is for jet lag. If you want to shift your body clock forward so that you wake up earlier (e.g., if you are travelling east), you should start light therapy shortly after waking up to signal the start of the day and suppress melatonin production, promoting wakefulness and alertness. 

However, if you want to delay your circadian rhythm so that you go to sleep later (e.g., if you are travelling west), you can use light therapy in the late afternoon or evening to delay your melatonin production.⁶

How to incorporate light therapy into your travel plans?

Before travel

You should try to start light therapy sessions a few days (up to 3 days) before you travel to gradually shift your circadian rhythm towards the time zone you are travelling to and prepare your body for the upcoming time zone change.

If you are going to be travelling east, try to get light exposure early in the morning. For westward travel, you could do light therapy later in the day to help you gradually delay your bedtime each day.^7,8

After travelling 

You can use portable light therapy devices to continue light therapy sessions while you are travelling to maximise its effectiveness.

If you have travelled east, you should use light therapy in the morning to help adapt to this earlier time zone. However, if you have travelled west, you should try light therapy in the early evening to help you stay awake for longer and adjust to this later time zone.^3,8

What are the potential risks of light therapy?

The benefits of light therapy for jet lag are clear: to accelerate the process of adapting to a new time zone, and reduce the severity and duration of jet lag symptoms. 

However, there are some potential risks and side effects associated with light therapy that should be carefully considered before you initiate this therapy for jet lag. These side effects can include:^9,10,11

• Headaches or migraines
• Temporary visual problems (e.g., eyestrain, blurred vision, tired eyes) 
• Nausea and vomiting
• Insomnia: Exposure to light at the wrong time (e.g., in the evening) or excessive light exposure can disrupt your sleep patterns and exacerbate jet lag symptoms. It is essential to adhere to a consistent light therapy schedule and avoid light exposure close to bedtime. 
• Hypomania: Individuals with a history of bipolar disorder may experience a state of hypomania in response to light therapy, associated with symptoms of nervousness, elevated mood, difficulty focusing, and hypersexuality, among other symptoms.^12,13 It is important to consult with your healthcare provider before using light therapy if you have any underlying mental health conditions. 

The majority of these side effects can be reduced by using a lower intensity of light during light therapy and making sure to take breaks as needed.

It is also vital to use light devices specifically designed for light therapy to treat sleep problems because other light devices not intended for this purpose might not filter out harmful UV rays. If these devices are used, there are more serious risks associated with UV light exposure, including:^14,15

• Increased risk of cancer
• Damage to the eye

Summary

Light therapy offers a promising approach for managing jet lag. It works by using timed light exposure to regulate your circadian rhythm and facilitate adjustment to new time zones, thereby working to reduce the severity and duration of jet lag symptoms. By understanding the principles of light therapy, adhering to best practices, and incorporating light therapy into your travel plans, you can use light therapy to optimise your travel experience and minimise the disruptive effects of jet lag. Combined with other jet lag management strategies, light therapy empowers travellers to make the most of their journeys and enjoy a smoother transition to new destinations.