In Norway we like to wear t-shirts inside, even in the middle of winter. And until quite recently, electricity prices have been low enough that most of us have been able to do so.
Now, however, much is changing. The energy crisis in Europe and periods of sky-high electricity prices here in Norway have led many to consider lowering the temperature in their living rooms.
But is this healthy for us?
If you are young and healthy, you can probably cope with a slightly cold house. But the elderly and those at risk of heart disease should keep the temperature higher in certain rooms, researchers advise.
According to Johan Øvrevik, we do not know for sure how indoor temperature affects health. He is a researcher at the Division of Climate and Environmental Health at the Norwegian Institute of Public Health, and professor at the University of Oslo.
But there are some signs which indicate that low indoor temperature has an impact on health.
One of them is the paradox surrounding the phenomenon we call excess winter mortality.
Influenza and heart disease
More people die in the winter than during summer.
Some of these deaths are due to increased mortality from influenza in the winter season. There is good reason to believe that the temperature plays a role here, Øvrevik notes.
The dry, cold winter air can inhibit the immune system.
“When you breathe in cold air, you get less blood flow in your nose, and thus fewer immune cells that can fight infections,” he says.
The dry air can also dry out the mucous membranes, which contributes to individuals being more easily infected by viruses. Additionally, it seems that viruses such as influenza and SARS-CoV-2 survive longer in dry air, so the risk of infection increases.
However, influenza only explains a minor part of excess winter mortality. Another significant cause is cardiovascular disease.