we already know that sleep with light can change the heart rhythms, affecting both our sleep and our health. It is believed that, for example, it may be related to the appearance of certain types of Cancer. Today, thanks to a study that has just been published in PNASwe also know how it can influence the development of diabetes and cardiovascular disorders.
The study in question, conducted by scientists from the Northwestern Universityanalyzes the causes that lead to these health problems and, in addition, provides tips to prevent this 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 day when it is not. This is where the light pollution problems begin. Its consequences on the observation of the sky are increasingly known, but making known the problems it causes to fauna, flora or even to ourselves remains a challenge. Now we have one more piece of information to try to raise awareness.
Can we sleep with light?
We have all heard the typical conversation between those who need absolute darkness for sleeping and those who claim to be able to do it even under the front door of the Seville April Fair.
It’s true, sleeping with the light on isn’t a problem for everyone. In fact, there are even people who need to be there a lamp to fall asleep. The problem is that, even if we perceive that it is not a problem for our rest, the lighting can still harm us.
It is because part of our the nervous system who should be lethargic. But to understand this a little better, we need to be clear about what they are. sympathetic and parasympathetic nervous systems. Because no, it has nothing to do with how people like you.
Types of Nervous System and Their Relationship to Sleep
Both at bedtime and during the day, our body’s control cabin is located in the brain. External and internal stimuli are continuously received and travel as nerve signals to this control booth, where the message is read and relevant commands are issued to respond to said stimuli.
All this framework communication between the brain and the rest of the body form the nervous system. But, in turn, this can obey different classifications. The main one is that which separates the nervous system into two types: the centralcomposed of the brain and surrounding organs, and the peripheralin which there are all these neurons that connect to each other to transmit information to the control cabin.
The sympathetic nervous system regulates the main activation responses during the day and the parasympathetic nervous system is responsible for the balance generated after
inside of it 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 responsible for regulating the bodily responses of Activation. is said to be very nearlyis what keeps us alert and active. the parasympatheticInstead, he is responsible for Balance and the regulation that must occur after activation of the sympathetic. It is therefore the one that begins at bedtime for inhibit activation which took place during the day. Finally, the enteric is that which is linked to certain emotional responses.
To talk about the harmful consequences of sleeping with light, we will 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 issues of sleeping with light on and being turned on when it’s not appropriate
During the day our cardiac frequency remains higher than overnight. It has evolutionarily helped us stay alert, in case we were to face danger. In addition, it allows us to be active and achieve all our daily tasks. At night, on the other hand, our whole body interprets that we are safe and therefore the time has come to reduce this frequency in the heartbeat. Also, secrete a hormone, llamada melatonina, that our sleepiness, decreases the body temperature and, in general, todo nuestro cuerpo is introduced in a species of system of ahorro de energía that compensates for the esfuerzo al that it has sometido during the 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. It usually affects sleep. But even if it doesn’t seem to bother us at bedtime, it can quietly affect us.
This is what the authors of the study which has just been published in PNAS. To do this, they put a group of volunteers to sleep with two different light intensities. 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 an elevated heart rate throughout the night. This, maintained over time, can be the cause of the development of cardiovascular disorders.
But that was not all. They also observed that in the morning after sleeping with the 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 several times in a row, the unused glucose ends up accumulating and can cause Diabetes.
Public lighting is also a problem.
These problems are not only the result of sleep with light in the bedroom. It is true that it is particularly harmful for people who sleep with a lamp or television on. But it can also happen if there is a public lighting whose light filters through the window. That is why it is important to close the blinds tightly or, if there are none, to use masks.
But what if we are not able to sleep with some light? Faced with such a situation, the authors of this survey gave some advice in a press release. For example, use very dim lamps, pointing to the ground. Also, more warm be the light, the better. Cool white lights, with a large blue component, are the ones that mainly inhibit melatonin secretion, affecting our sleep. And, in addition, they can keep the sympathetic nervous system active.
If you can clearly distinguish the silhouettes of objects in the room, it means that there is too much light
On the other hand, if we don’t have a mask, we don’t have blinds or these let light in through the slits, 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, because in this way the light of the morning sun would help us to wake up gradually. But of course, that would only be in the event that there was no artificial lighting on the streets.
In short, the best way to know if we have a proper lighting is to check that at bedtime the objects in the bedroom do not stand out. If we can see the figures clearly, there is too much light in this room. And the consequences, as this study points out, can be very serious.
