we already know that sleep with light can alter the Cardiac rhtyms, affecting both our sleep and our health. It is believed that, for example, it may be related to the appearance of some types of Cancer. Now, thanks to a study just published in PNASwe also know how it can influence the development of diabetes and cardiovascular disorders.
The study in question, carried out by scientists from the Northwestern Universityanalyzes the causes that lead to these health problems and, in addition, provides tips to prevent it from happening. All this without forgetting to explain the reasons why these imbalances occur.
And it is that, in general, our body prepares us to be alert during the day and rest and reset us overnight. But if the brain detects the entry of light, it can interpret that it is daytime when it is not. This is where the problems of light pollution begin. Its consequences on the observation of the sky are becoming more and more known, but making known the problems it causes to the fauna, the flora or even to ourselves continues to be a challenge. Now we have one more piece of information to try to raise awareness about.
Can you sleep with light?
We have all heard the typical conversation between those who need absolute darkness to sleep and those who claim to be able to do it even under the entrance door of the April fair in Seville.
It is true, sleeping with light is not a problem for everyone. In fact, there are even people who need to be around a lamp to fall asleep. The problem is that, although we perceive that it is not a problem for our rest, the lighting may be harming us anyway.
This is because a part of our nervous system that should be lethargic. But to understand this a little better, we must be clear about what they are. the sympathetic and parasympathetic nervous systems. Because no, it has nothing to do with how well people like you.
The types of the nervous system and their relationship with sleep
Both at bedtime and during the day, the control cabin of our organism is located in the brain. External and internal stimuli are continuously received and travel in the form of nerve signals to that control cabin, where the message is read and the pertinent orders are issued to respond to said stimuli.
All that framework communication between the brain and the rest of the body forms the nervous system. But, in turn, this can obey different classifications. The main one is the one that separates the nervous system into two types: the centralcomposed of the brain and nearby organs, and the peripheralin which all those neurons that connect with each other to carry the information to the control cabin are found.
inside that peripheral nervous system we found something known as autonomic nervous systemwhich refers to all the components that regulate involuntary actions, such as control of reflexes, breathing, blood pressure, or digestion. Now, in an even more detailed classification, the autonomic nervous system is made up of sympathetic, parasympathetic, and enteric.
The sympathetic is the one that is in charge of regulating the bodily responses of activation. Said of very roughlyis what keeps us alert and active. The parasympatheticInstead, he is responsible for Balance and regulation that must occur after activation of the sympathetic. Therefore, it is the one that starts at bedtime to inhibit activation that has taken place during the day. Finally, the enteric is the one that is related to certain emotional responses.
To talk about the harmful consequences of sleeping with light, we are going to focus on the sympathetic and the parasympathetic. And it is that it is a confusion between the two that leads precisely to these effects.
The problems sleeping with light and being activated when it is not appropriate
During the day, our heart rate remains higher than at night. This has evolutionarily helped us stay alert, in case we had to deal with any danger. In addition, it allows us to be active and carry out all our daily tasks. At night, on the other hand, our entire body interprets that we are safe and that, therefore, the time has come to reduce that frequency in the heartbeat. In addition, a hormone called melatonin is secreted, which helps us sleep, lowers body temperature and, in general, our entire body enters a kind of energy-saving system that compensates for the effort it has undergone during sleep. day.
The problem is that if we go to sleep with light our brain interprets that it is daytime and, therefore, the sympathetic nervous system continues to keep us active and alert. This usually affects sleep. But even if it doesn’t seem to bother us at bedtime, it may be quietly affecting us.
This is what the authors of the study that has just been published in PNAS. To do this, they made a group of volunteers sleep with two different intensities of light. The first group did 100lux, what is considered moderate lightand the second to 3luxequivalent to a very dim light. They saw that those in the first group maintained a high heart rate throughout the night. This, maintained over time, may be behind the development of cardiovascular disorders.
But that was not all. They also observed that the morning after sleeping with light there was a increased insulin resistance. This means that, at normal insulin levels, cells are unable to use glucose. Therefore, a larger amount is needed. If such a situation occurs many times in a row, eventually unused glucose accumulates and can cause diabetes.
Street light is also a problem.
These problems are not only the result of sleep with light inside the room. It is true that it is especially harmful for people who sleep with a lamp or the television on. But it can also happen if there is a streetlight whose light filters through the window. That is why it is important to close the blinds well or, if there are none, use masks.
But what happens if we are not able to sleep with a little light? Faced with such a situation, the authors of this research have given some advice in a release. For example, use very dim lamps, pointing to the ground. Also, the more warm be the light, the better. Cold white lights, with a large blue component, are the ones that mainly inhibit melatonin secretion, affecting our sleep. And, in addition, they can cause the sympathetic nervous system to remain active.
On the other hand, if we don’t have a mask, we don’t have Blinds or these let light in through the cracks, we should at least place the bed so that the light does not fall on our face while we sleep.
In fact, the ideal would be not to have to use blinds, since this way the sunlight in the morning would help us to wake up progressively. But of course, this would only be in the event that there is no artificial lighting in the streets.
In short, the best way to know if we have a correct lighting is to verify that, at bedtime, the objects in the room are not distinguishable. If we can see the silhouettes clearly, there is too much light in that room. And the consequences, as this study points out, can be very serious.