Category Archives: Light Exposure

Sleep and Your Television: What’s Going Wrong?

We have known for some time that television watching can disturb sleep. In fact, several studies have demonstrated that in children, adolescents, and adults, television watching not only inhibits falling asleep, but also staying asleep, even after it is turned off. We now have a study published in the March issue of the journal Chest titled Sitting and Television Viewing: Novel Risk Factors for Sleep Disturbance and Apnea Risk? Results from the 2013 National Sleep Foundation Sleep in America Poll.
Over 1000 volunteers in this study were asked questions about how long they sat watching television daily, and questions about the quality and duration of sleep. They also answered a questionnaire that is very sensitive for sleep apnea.
The findings were truly remarkable. As expected, sitting for long periods was associated with poorer sleep quality. However, sitting in front of the television for prolonged periods was associated with a longer time to fall asleep, waking up too early in the morning, and a “high risk” of sleep apnea.
We have known for some time that sedentary behavior can cause sleep problems. In fact, several studies have shown that people who exercise regularly report better sleep quality and duration. Another study published in the journal Sleep in 2011 titled The Effect of Exercise Training on Obstructive Sleep Apnea and Sleep Quality: A Randomized Controlled Trial, demonstrated that exercise independent of weight loss resulted in an improvement of sleep apnea in individuals performing 150 minutes per week of moderate intensity aerobic exercise.
This is the first study to demonstrate that sitting while watching television is associated with sleep apnea. Interestingly, this relationship held for both obese and non-obese subjects. It certainly makes sense that those who are more physically active spend less time in front of the television. However, as to why those who sat in front of the TV, as opposed to those who sit but do not watch had a greater propensity to develop sleep apnea is not known at this time. It is theorized that most TV watching occurs close to bedtime, resulting in the blue light exposure effects on sleep. Also, late fluid changes in response to sitting, which may contribute to sleep apnea, are occurring closer to bedtime.
The take home message is that a sedentary way of life is bad for your health and sleep. However, it would appear that a sedentary life style mixed with excessive television watching is much worse. If you want good healthy sleep, get up and turn off the television.

Let the Sunshine in to Sleep at Night

In the 1960’s, the musical Hair featured a song titled Let the Sunshine In. Little did we know back then that it might become a clarion call for modern day architecture. According to a recent study, poorly lit and windowless work environments can have significant adverse mental and health-related outcomes. The key appears to be the effect of daylight on our sleep.

The researchers studied 49 workers for a period of two weeks. Half were in a windowless work environment and the others in workplaces with significantly more daylight. They were studied with an actigraph, which is a motion detector that differentiates sleep from wakefulness. The researchers also administered questionnaires that monitor quality of life and quality of sleep during this period.

The results were striking. Workers in windowless environments scored poorly with regards to quality of life. They were more likely to complain of physical problems and fatigue. Most importantly, they demonstrated shorter sleep duration as measured by the actigraph. This is in agreement with other studies that have demonstrated that short sleepers have more ills that are physical and are more fatigued than normal sleepers are. What is most interesting is the influence of workplace lighting on their sleep.

Why does light exposure affect sleep? It probably has to do with our circadian clocks. Light is the strongest stimulus of all in maintaining a stable sleep/wake schedule. Specifically, light exposure during the day, especially in the morning, helps us to fall asleep at a regular time each night. It would appear that workers in poorly lit environments do not have this stimulus and as a result, their sleep is affected.

Poor sleep results in elevation of stress hormones such as cortisol, impairment of glucose metabolism, increased appetite, as well as increased fatigue and decreased mental alertness. All of which, as the authors point out, can lead to increased error rates and injury in the workplace environment.

Why is this important? It is the first study to accurately reveal the negative effects of a poorly lit environment on sleep and thus health. It should motivate architects to bring more light into office buildings and might encourage workers to avoid poorly lit cubicles. If you are stuck in such a building, you might consider increasing the amount of artificial light in your workspace. Alternatively, if weather permits, go outside for your morning coffee break or lunch. Like the song says, let the sunshine in.