Blue Light and the Effect on Sleep

Original Editor - User Name

Top Contributors - Kapil Narale and Angeliki Chorti

What is Blue Light?

Blue light which comes from electronic devices, such as the television, computers, and smartphones are known to be harmful. These devices have become a permanent means of entertainment and communication, and are widely used in daily life. Blue light can also have beneficial effects as it can impact performance and wellbeing. Blue light is emitted with a wavelength that impacts our circadian rhythm and thus can result in poor sleep.

Negative Effects of Blue Light

There are a range of negative effects that blue light can cause:

• Decrease in tiredness
• Decrease in sleep quality
• Decreased sleep duration
• Decreased sleep efficacy
• Increased time it takes to fall asleep

Factors like a decrease sleep quality and duration can have a negative effect on an athlete's physical and cognitive performance, as well as their recovery. It has been found by Tordjman et al (2017), that blue light halts the secretion of melatonin. The main role of melatonin is to regulate the circadian rhythm, the part of the body that effects sleep.

Studies have found that there was a decrease in individualsed sleepiness with the exposure of blue light. A study found, as mentioned below, that tehre was a higher individualised sleepiness level with the use of blue light blocking glasses

Benefits of Blue Light

Some benefits include:

• Increase in cognitive performance
• Increase in alertness
• Decrease in reaction time
• Increase in wellbeing

It is interesting ot note that the increase in cognitive performance, alertness, wellbeing, and decrease in reaciton time can aid in sport performance, when relying on teamwork and decision making, and thus can help prevent injury.

It is interesting to note that exposure to blue light is an effective treatment method to cure major depression symptoms, stimulates cognitive brain activity, and improves physical performance.

Blue Light Blocking Glasses

Various studies, as outlined in the systematic review by Silvani et al (2022), indicate he effectiveness of blue light blocking glasses compared to other methods:

• A study examined reading before bedtime on an iPad vs. a hard copy book for 30 minutes. There was no significant difference in sleep duration or time to fall asleep between the blue light and non-blue0light conditions. Individualised sleepiness was significantly decreased in the blue-light condition.
• A study examining playing games before bed on an iPad vs. an iPad with a short wavelength filter, for 48 minutes, found that time to fall asleep, and individualised sleepiness howed no significant change between the blue-light conditions.
• A study examining smartphone use in the morning with the conditions of smartphone use vs. smartphone use with a display filter, for 150 minutes, found that there was a significant decrease in sleepiness in the blue-light condition.
• A study that examined office work and sitting during work hours, for 3 weeks, in a blue-light vs. white-light condition, found that sleepiness was significantly increased in the blue-light condition.
• A study examined elite athlete training with blue-light emitting activities during the hour before bedtime

Importance to Athletes

the positive and negative factors from the exposure to blue light is a consideration to athletes, especially since a good sleep hygiene is essential for a strong athletic performance. It is also a possibility that blue light may improve performance, especially since athletes may be in need of sleep as a result of their busy training schedules.

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