Wind farm noise may disrupt sleep

In this article, researchers surveyed the sleep quality of people living near and far from farm turbines. The results showed that the closer a person live to the wind farm, the more disrupted their sleep, secondary to the noise generated by the turbine. Persons close to the turbine also had poorer mental health. My first thought was that perhaps the difference in self-reported sleep and mental health was due to being lower socioeconomic status, but the study authors said they controlled for that.

Weight loss may improve sleep quality

This article discusses research showing that modest weight loss (about 15 pounds) may improve self-reported sleep quality by 20%. I've seen this happen in my clinic, and the results can be impressive. Researchers think that belly fat may be responsible for sleep disruption, and losing the belly fat may be what helps improve sleep.

Insomnia increases cardiovascular risk?

Many of my patients with insomnia are understandably worried about the physical effects of insomnia. They are concerned that their insomnia will lead to cardiovascular disease (heart attack or stroke, for example) or death. To date, no studies have convincingly shown that primary insomnia increases risk of physical problems - it has been shown to increase rates of depression.

Here is an article about a study trying to link insomnia to increased risk of heart attack and stroke. However, the study authors did not separate the different types of insomnia, meaning the results are difficult to interpret. More specifically, they did not separate the effects of primary insomnia from secondary insomnia (as from sleep apnea) and even people who just decide to get too little sleep. Since the last two categories of insomnia can increase cardiovascular risk, it could make all insomnia seem risky, but this is artificial.

Young children with cystic fibrosis at risk for obstructive sleep apnea

This article discusses how young patients with cystic fibrosis, a chronic lung disease, are at increased risk for obstructive sleep apnea.

Chronic sleep loss in rats

Studies and news reports keep coming about how sleep loss / sleep deprivation is associated with obesity and type 2 diabetes - but the studies are far from conclusive. One problem is that it is difficult to control diet and sleep behavior in humans over a long period of time. Animal studies may help us understand the link between sleep and obesity, since animals can be controlled in the lab. Animal studies in the past have shown links between sleep loss and metabolic changes, but this is usually weight loss and could be due the stress of forced wake time.

Vetrivelan et al have performed an interesting study on rats published in this month's Sleep Journal. They produced brain lesions in the hypothalamic regions of rats as an animal model for chronic, partial sleep loss, and they followed the rats for 2 months (relatively long time for a rat).

Results showed that on average, the brain lesions resulted in 40% reduced sleep compared to normal rats - equivalent to reducing sleep from 8 hours to 4.8 hours per night in humans. However, the rats with brain lesions did not become obese or develop metabolic syndrome. In fact, there was a decrease in blood glucose, cholesterol, and triglycerides!

The authors are not sure why there is a different response in rats and humans to sleep deprivation. When humans voluntarily go without sleep, their food intake increases and are less active. However, the rats in this study did not consume more food and were more active than control rats. The authors concluded that chronic sleep loss per se does not lead to obesity or the metabolic syndrome, at least in rats.

General anesthesia similar to sleep

This article discusses research discussing how general anesthesia may cause deep sleep. Researchers studied the brains of mice under anesthesia and found that the anesthetics turn off wake-promoting neurons and turned on sleep-promoting neurons. However, anesthesia is still not normal sleep. But general anesthesia can allow anesthesiologists to identify individuals at risk for obstructive sleep apnea - I get frequent referrals for this very problem, since the anesthesiologist is "watching them sleep" for hours!

Electronic nose may be able to detect sleep apnea

Although I did not even know they existed, electronic noses have been developed to diagnose certain medical disorders. This article, researchers discusses a study to determine if an electronic nose could detect obstructive sleep apnea (OSA), by measuring volatile compounds in the patinents' breath. It's not clear how the researchers determined if the participants had OSA, as the article mentions only "sleep examinations." If that means sleep studies, then that would be more accurate. The results did show that the electronic nose did predict OSA. They concluded that the electronic nose could help determine who needs a sleep study and who does not.