Among the many tips to stay safe from coronavirus is getting a full night’s rest, according to AmeriSleep. Practicing good hygiene and staying at home are vital, but it’s also important not to overlook the value of sleep. Boosting your immune system is just one of the functions of sleep.
In every nation on Earth, people are taking precautions to protect themselves and their loved ones from contracting the novel coronavirus, SARS-CoV-2. In the middle of all the preventative suggestions being offered, mattress and bedding company AmeriSleep has recommended ensuring a healthy sleep schedule. It may sound like a sales pitch, but there’s merit to the claim.
“In addition to washing your hands with hot water and soap, avoiding contact with those who are sick, and frequently disinfecting commonly touched surfaces, one of the best ways to protect against this virus is to boost your immune system,” a letter on the company’s website said. “Since sleep is a natural immune booster, getting a good night’s rest is one way you can protect yourself.”
This ties into the theory of sleep as a restorative function.
Restorative Sleep at the Chemical Level
Several theories still compete regarding the full list of reasons that we sleep, but one stands out.
“Here is the hypothesis for today: The function of sleep is to enable the restoration of the brain energy reserves, namely glycogen,” said Dr. H.Craig Heller, the Lorry I. Lokey/Business Wire Professor of Biological Sciences and Human Biology at Stanford University. “The roots of the hypothesis go back to the discovery that a major signal controlling [electroencephalogram] slow-wave activity during sleep is the molecule adenosine. The major coinage of energy exchange and utilization in the body is ATP, or adenosine triphosphate.”
One of Dr. Heller’s colleagues, a graduate student named Joel Benington, developed this hypothesis before going on to become a biology professor at St. Bonaventure University in New York. He demonstrated the link between adenosine and brain activity.
“When he injected a molecule that mimics the action of adenosine into the blood or into the brains of rats, they showed what appeared to be normal deep sleep for several hours with very high slow-wave activity,” Dr. Heller said. “That slow-wave activity gradually declined as the animal slept, just as it does during normal sleep.”
What This Means for You
The link between sleep and various adenosine molecules like ATP may sound a bit abstract, but it holds the key to understanding the restorative function of sleep. First, we need to look at glycogen and the brain.
“The brain needs glucose, [which] comes from the blood, but the blood supply to specific brain regions cannot change as rapidly as the neuronal activity in those brain regions can change,” Dr. Heller said. “To solve this problem, the brain has an energy reserve in the form of glycogen, a polymer of glucose, in the glial cells. The glial cells synthesize glycogen when there is an abundant supply of glucose in the blood.”
These glycogen reserves are like spare gasoline cans in the trunk of a car. When glucose levels fall, Dr. Heller said, glia break glycogen back down into glucose for use. This process is called glycogenolysis. So what does this have to do with sleep?
“The story is that during wake, the glia are poised to give up their glycogen at a moment’s notice if energy levels start to fall,” Dr. Heller said. “During sleep, the glia are put into the mode of replacing their glycogen stores.”
In other words, while we sleep, the glia are packaging and storing the brain’s spare fuel to get us through the following day. Sleep restores our energy supplies.
Dr. H. Craig Heller contributed to this article. Dr. Heller is the Lorry I. Lokey/Business Wire Professor of Biological Sciences and Human Biology at Stanford University. He earned his Ph.D. in Biology from Yale University.