This Sunday morning at 3am our clocks go back to 2am. Everybody copes differently with the change from summer to winter time. Some people feel low in the winter months, and are then euphoric when summer arrives and the days are longer. Independently of how we feel, there is something that marks the rhythm of our interior clock: the light, says Jesús Romero Imbroda, who is the head of Neurology at the Quirón hospital in Malaga.
As well as explaining how changing the hour affects our health, this specialist also warns that this year differs to others. We are in the midst of a pandemic which - what a surprise - can also affect our health with regard to the imminent onset of winter time.
As a doctor, are you in favour of changing the hour or not?
In principle, it isn't a question of taking a group decision on whether it is something positive or negative. It is an artefact of political regulation. If they tell us the reason for it is that it saves energy, and it is beneficial for the economies of countries, I have no objection. The problem this year is related to the pandemic. Due to the lockdown in March, people have enjoyed fewer hours of sunshine than normal. When the hour changes at this time of year, the days get shorter. Because of lower exposure to the sun, which is what we have seen during the pandemic, there could be problems in the long term. For example, vitamin D deficiencies.
Why do we talk about summer time and winter time? Is there a scientific reason or are they just names?
There is no specific scientific reason. I understand it is that way because the time changes before the start of summer and the start of winter. Nothing more than that.
Are we human beings guided by daylight?
Absolutely. Our biological changes are linked to the Circadian rhythm. That is the number of hours we sleep and the number of hours we are awake. Light is essential to all that. Light stimulates a series of mechanisms and darkness causes other changes which facilitate sleep, and those are associated with the recuperation of the systems involved in the human body.
Does the change in the hour disturb our internal body clock?
The change in the hour does disturb it, yes, but so does the arrival of winter. That has been shown in studies of people in Northern European countries who have little exposure to the sun. There, the incidence of depression and other psychiatric pathologies is greater. In the Latin countries, where there is greater exposure to the light and you can be outside more, the incidence of depression is lower. There is a clear seasonal characteristic in psychiatric pathologies.
This internal clock; is it the same, and does it work the same way for everybody?
In terms of health, yes. The chronometer is determined by the pineal gland, which is a gland in the brain that segregates the hormone called melatonin. The secretion of melatonin is stimulated by an absence of light, when we are going to sleep. When we induce sleep, the melotonin is segregated and that helps us to sleep.
So how does the change in the hour affect our rest?
The change to summer time has a greater effect than the change to winter time. When we go into summer time, we sleep an hour less. Sleeping less can lead to irritability and anxiety. Now we will sleep an hour more, so it will be easier to adapt to the change. Although you also have to remember that it is anomalous for us to lose hours of daylight.
What effects can this change of the hour have at a neurological level?
With regard to health, it has been clearly shown that the change in the hour makes us more irritable. In some cases it can lead to anxiety. That mainly happens in the first few days.
Does the change in the hour affect adults and children in exactly the same way, or are there differences between them?
There are some differences. Children adapt better. They barely notice the change. That means they absorb it better. Adults, whose hours of sleep are very defined and organised, notice it more.
For many people, the change to winter time makes them feel sad. Is the lack of daylight the only reason for that?
I would say to a large extent, yes. We human beings think we are very capable but in fact we are strongly linked to the climate, time, atmospheric pressure and changes in the season. We see that in illnesses. Epileptics, for example, have more convulsions when there is a full moon. And we still don't know why that is. When there are atmospheric changes, patients who get migraines suffer much more. If your sleep is disturbed and you suffer from pathologies like depression, you are going to feel even more sad. Then that sadness is due to the change in sleep pattern and fewer hours of daylight. Some illnesses have a seasonal pattern. There is more depression in winter. Light makes the brain happy, it is the element that switches it on.
We are still in the midst of a pandemic. Would further restrictions or even another lockdown make the change to winter time feel even worse?
Yes. The situation would be more difficult. In a new lockdown, for example, the scenes where people went onto their balconies to clap for the emergency services wouldn't happen again. It will be dark, cold and rainy. Those hours we spent outside in the light, in homes which had outside space of course, were very healthy for us during lockdown. Winter time worsens the consequences of possible restrictions or lockdowns. As a neurologist, it worries me, especially, that elderly people will get worse because of a lack of cognitive stimulation.
In other words, it would be a lockdown with fewer hours of daylight.
Right now, we are seeing the consequences of locking down a population. I am one of those who believe that there is a danger in lockdowns. Above all, for illnesses which are not Covid. We see that the health system can't cope and delays ensue. With regard to lifestyle, which is what interests people in general, a lockdown with fewer hours of daylight is likely to be more detrimental for the health than the last one.
Can you give us some advice or recommend what we can do to mitigate the effects of the change in the hour? ?
Don't anticipate or bring forward the change in the hour in an attempt to acclimatise the body, but don't resist it either. Just act normally, as if the hour hadn't changed. In two or three days your body will have adapted. In other words, don't anticipate or delay that adaptation. Just go along with it.