On Saturday, the web service of the Finnish Meteorological Institute carried the notice: "Cold warning: In the eastern part of the country and also in provinces Päijät-Häme, Central Finland, Kainuu and northeastern Ostrobothnia during the coming 24 hours, cold weather may cause health problems for groups at risk."
People who have health problems should take these warnings very seriously and take the proper precautions.
"The effects of the cold, naturally, have an impact through areas of bare skin. For example, one's face is usually not covered," notes Professor Simo Näyhä of the University of Oulu.
"Blood vessels in the skin contract and blood pressure rises. This in turn causes higher blood pressure that may be damaging to the heart. There may be plaque loosened that causes problems," he continues.
The composition of blood is affected by the cold.
"The tendency of blood to clot increases and this may give rise to clots in the veins. These then can cause acute illness and even sudden death."
Cold temperatures also promote infections.
"It has long been known that there are more infections during the cold part of the year. It may be that, for example, viruses indirectly cause coronary thrombosis. The reason why there are more infections during the cold season is not completely clear. Part of the reason, certainly, is that people spend more time indoors, thus increasing the possibilities of catching an infection," says Professor Näyhä.
More deaths in winter
Since the 1700's it has been recognized that mortality rates increase during the winter. This is not mainly due to deaths from hypothermia, but rather from illnesses induced or exacerbated by the cold.
Each winter 2,500-3,500 deaths are registered as occurring from natural causes, such as heart disease, cerebral haemorrhage or pulmonary disorder that are directly or indirectly the result of the cold.
The number of people who actually freeze to death is around 70-80 each winter. Usually these cases are associated with alcohol abuse.
Put on a cap
Inhabitants of Finland usually do quite well surviving the winter. When the cold arrives, people know what to do to avoid problems.
"People in Finland know quite well how to dress," observes Näyhä. "In addition, people with medical conditions notice the symptoms that the cold causes, for example chest pains, and they avoid the worst by being aware of when it's dangerous for them to go out."
Even so, after each heavy snowfall, many people end up seeking medical care following the exertion of shovelling snow in sub-zero temperatures.
Caution should be a byword.
"Make sure that treatment and medication for any disorder are right. One must also use common sense. If symptoms appear, such as chest pain or wheezing, one should slow down and go someplace warm. These symptoms are always warning signs," he adds.
Näyhä also confirms that what mother said was right: when it's cold, put on a cap and long underwear.
"All of the body's extremities, such as arms and legs, should be covered."