Being too cold indoors can be bad for your health

We in Norway love to wear shirts inside, even in the middle of winter. And until very recently, electricity prices were low enough that most of us were able to do so.

Now, however, there are a lot of changes. The energy crisis in Europe and periods of high electricity prices here at home have led many to consider lowering the temperature in the living room.

But is it good for health?

If you’re young and healthy, chances are you can handle a slightly colder home. But researchers advise the elderly or other people at risk of heart disease to maintain a higher temperature in certain rooms.

You can read a list of researchers’ tips below in this case.

Dangerous winter

The truth is, we don’t know for sure how indoor temperature affects health, says Johan Overvik, director of research in the Department of Climate and Environment at the Institute of Public Health and professor at the University of Oslo.

But there are some hints that a lower indoor temperature actually has an effect on health.

One is the paradox surrounding the phenomenon we call winter excess mortality.

Influenza and heart disease

More people die in winter than in summer.

Some of these deaths are due to increased deaths from influenza in the winter season. There’s good reason to think temperature plays a role, Overvik says.

Cold, dry winter air can suppress the immune system.

– When you breathe in cold air, the blood flow in your nose decreases, so the number of immune cells that can fight infections decreases, he says.

Dry air can also dry out your mucous membranes, which also contributes to you catching viruses more easily. In addition, viruses such as influenza and SARS-CoV-2 appear to live longer in dry air, so that the risk of infection increases.

However, influenza only accounts for a fraction of the winter deaths. Another important reason is cardiovascular disease.

The north-south paradox

Most people who die from heart disease in Norway are over 65 years old. On average, 1,800 people die in summer months like June, while the figure for January is as high as 2,500, says James Mercer, professor emeritus at Norwegian Arctic University UiT.

He has been interested in this phenomenon for decades.

These excess deaths in winter are well known throughout Europe. But the irony is that the problem is not severely affected where the winters are colder. exactly the contrary.

The difference in mortality between summer and winter is smallest in Norway, Finland and other Scandinavian countries. It is largest in southern European countries such as Malta, Portugal and Cyprus, where the winters are mild.

This may indicate that the internal temperature has something to say, think of both Mercer and Øvrevik.

Compare homes in Tromso and Dublin

Perhaps it has something to do with the house standards.

Norwegian homes are generally built to keep out the cold. They are well insulated and have efficient heating systems, such as the heating cables in the bathroom.

Mercer did a few years ago study Indoor temperature in seniors’ homes in Tromso and Dublin, Ireland.

Temperature gauges have been installed in all living quarters of 25 homes in each city. The meters record the temperature every two hours throughout the year.

The results showed significant differences.

13 degrees in the bathroom

– In Tromso, the temperature in the living room was 22 to 23 degrees all year round, while in Dublin it was an average of 20, says Mercer.

The situation was much worse in many of the other rooms.

– In Irish kitchens the temperature was as low as 15 to 16 degrees in winter. The baths in Tromso kept the temperature at 23 to 24 degrees, while the bath in Dublin was as low as 13 degrees in the winter.

In Norway, indoor temperatures remained fairly constant throughout the year, while in Ireland there was a wide variation between summer and winter.

The exception was the bedroom. There, the bedrooms in Tromso were about 14 degrees, while in Dublin it was around 16-17 degrees.

– Norwegians like to sleep with the window open and have good bed linen. It’s the opposite in Ireland, Mercer says.

Several signs indicate an indoor climate

We don’t know for sure if it is such conditions that mean the winter death rate is significantly higher in Ireland and many other European countries than in Scandinavia. But there is ample evidence pointing to this trend, as well as the disparity in winter mortality across different countries.

Mercer says that in the 1950s, for example, there was a great change in home heating in Great Britain and Ireland.

– They started central heating of homes. And it had a significant impact on the death rate.

Mercer believes another indicator is the population of one of the coldest cities in the world, Yakutsk in Siberia.

It has very low outdoor temperatures for large parts of the year, and the average January temperature is minus 40 degrees. However, the population has almost no increase in cardiac deaths in the winter.

However, they do have comfortable indoor temperatures and are very good at dressing nicely when out and about.

It mostly applies to people over 65 years old

The elderly are primarily at greater risk of dying when a cold begins. It may have physiological explanations.

As we age, changes occur in the body that make it harder to handle cold temperatures, says Mercer.

– We have reduced metabolism and muscle mass, and many have less fat. In addition, we are often less active and have a reduced ability to shiver. Some older people also have less sensitivity to cold. They don’t really notice that they are catching a cold.

Mercer also has research results that show that the skin temperature of older people is slightly lower than that of younger people. And in experiments in which the hands and feet were cooled in a controlled manner over a short period, it took older adults longer to regain heat.

blood pressure and cholesterol

At the same time, other changes occur that increase the risk of heart disease.

Blood pressure rises, and cholesterol and triglyceride levels in the blood increase. Research has shown that these risk factors vary over the course of the season and are worse in the winter.

– When you feel cold, the blood vessels on the surface of the skin, especially in the legs and arms, will constrict to conserve heat in the important internal organs, explains Øvrevik from the Institute of Public Health.

Then the blood also has less room to stay, and blood pressure rises.

A Japanese study from 2019 just showed that lower indoor temperatures led to higher blood pressure, especially in older men. If you already have high blood pressure, this could be the last straw for something serious to happen to your heart.

– Worrying

The researchers don’t want to scare anyone.

Most younger, healthy people will tolerate lower indoor temperatures just fine, says Øvrevik.

When it comes to the elderly, it is different. It’s good here to realize that a very low indoor temperature can be unfortunate, especially if it’s less than 18 degrees. Therefore, the elderly and people with cardiovascular diseases should be careful not to be exposed to extreme cold indoors.

– One can imagine a number of lower pensioners thinking about keeping cool to save electricity. He says it’s a little worrying.

Mercer generally thinks it’s a good idea to save some energy usage by lowering temperatures a bit in Norwegian homes. But not much.

He fears that significant savings in electricity will make Norway more like Ireland and other countries that have larger differences in mortality between summer and winter. It is not desirable.

One tip for the elderly — and another for young people who are out in the cold

Mercer recently offered some clear advice for seniors, in a pamphlet in collaboration with the Lions Club organization in Varanger:

• Get a thermometer inside. It could be a good clue.
• If you feel cold, it’s cold, no matter what the thermometer shows. Get dressed and turn up the temperature.
• Keep at least one room in the house – for example the living room – really warm. Preferably 24 degrees or more
• Maintain a high temperature in the bathroom, where you often wear light clothes.
• Feel free to keep it cool in the bedroom, but make sure you have good, warm bed linen.
• Keep moving a little bit. It increases body temperature and maintains muscle mass.
• Dress well. Several thin layers of clothing are better than one thick layer.
• Eat hot food and drink hot drinks.
• Avoid alcohol. It can feel like a warming sensation, but in reality it causes your blood vessels to open up and so you lose heat.

Finally, Mercer will give a little advice to young people as well.

Avoid using snuff and tobacco if you are going out in the cold. Nicotine has the ability to dilate blood vessels, so that they lose heat, for example in the hands and feet.