Shift Work

Improving Health and Productivity for Shift Workers through Light Therapy

Many shift workers know they don’t sleep well and aren’t performing their job to the best of their abilities. Some also know that working the night shift or rotating shifts puts their health at serious risk. But what few may know is that they can improve their sleep and productivity and reduce their health risks by controlling their exposure to light through light therapy.

The Root Cause

The root cause of the problems shift workers face is a body clock that is out of synch with their daily schedule. Our body clock refers to the internal systems inside our body that regulate our physical and mental functions over the course of a day, known as our circadian rhythms. These rhythms are normally synchronized with the solar day and when they are working properly, we sleep soundly through the night and are active and alert during the day, a cycle that promotes overall good health. For those who do shift work during normal sleeping hours the body clock is frequently out of synch. While they work their body wants to sleep and when they try to sleep their body expects to be awake. This mismatch between the body’s inner clock and the clock of the external environment they are trying to function in often means that they feel tired and foggy at work and later have trouble sleeping. Shift workers typically sleep one to four hours less than average. When this mismatch and sleep deprivation becomes chronic the result is a circadian rhythm sleep disorder that has serious consequences, including increased risks for:

  • Insomnia
  • Anger
  • Anxiety
  • Depression
  • Fatigue
  • Heart disease
  • Deterioration in performance
  • Becoming injured on the job
  • Diabetes
  • Cancer

How the Body Clock Works

Light and darkness are what regulate our body clock. Specialized cells in the retina at the back of our eyes, called photosensitive ganglion cells, detect the presence of light or darkness and carry this information to the brain, which in turn signals the release of various hormones. When no light is detected, the eye sends the signal to the pineal gland in the brain to begin releasing melatonin—the ‘hormone of darkness’—that makes us feel tired, promoting a good, healthy night’s sleep. But melatonin does much more than regulate our sleep. Research has shown that it strengthens our immune system and that low levels of it are associated with cancer, diabetes and heart disease. Because small amounts of light can dampen the flow of melatonin, shift workers trying to sleep during the day can experience suppressed melatonin, which on the one hand makes sleep difficult and on the other hand increases various health risks.

The Impact of Light on Our Health

Darkness is one half of the body clock equation. The other half is light. When light hits our eyes, our brain tells our body to stop making melatonin, and instead to start producing other hormones, such as serotonin, which wakes up the body. If someone working a night shift doesn’t receive sufficient light during the hours in which they are supposed to function, their bodies don’t produce adequate amounts of serotonin, making them feel tired. But like melatonin, serotonin does more than just affect our sleep/wake cycle. Serotonin is a mood enhancer, which is why it is commonly referred to as the happiness hormone. Low levels of serotonin, common in shift workers, are associated with anger, depression and anxiety. And because low levels make it difficult to sleep soundly, disrupting melatonin production, a vicious cycle ensues in which normal hormonal rhythms remain derailed and performance and health continue to suffer.

Resetting the Body Clock through Light Therapy

To help shift workers feel better and to reduce the health risks associated with circadian rhythm disruptions, researchers and health professionals have been turning to light therapy. For a shift worker, a light therapy program synchronizes the cycle of light and darkness to the work and sleep schedule, providing sufficient light during the worker’s ‘morning’ and ‘day’ and complete darkness during sleep. Because natural light isn’t available to provide the necessary illumination for someone working at night, specially designed artificial light sources, such as YumaLite™, are used at the appropriate times. Mimicking the natural cycle as much as possible appears to be ideal, as research has shown that the benefits of exposure to light during waking and working hours—improved alertness on the job and better sleep later on—can be enhanced by workers wearing sunglasses on the way home as a way of creating an artificial dusk.

For shift workers, as well as their employers, who rely on their productivity and good health, light therapy offers a simple and easy-to-use method to help the body clock adapt to the worker’s unnatural schedule, improving job performance and alleviating the health risks associated with circadian rhythm sleep disorders.


YumaLite™ is a head-mounted light therapy visor created with the shift worker in mind. It uses clinically proven technology that is effective and safe. It has been ergonomically designed by award-winning designers as a lightweight cordless visor that rests comfortably on the head so that it can be easily worn while having breakfast and getting dressed and ready for work. YumaLite™ is also compact and portable, which makes it easy to take to the job site, where it can be worn on break, or—where safe and appropriate—during work.

Please see studies and research related to shift work and light therapy.