- Danish researchers recruited eight men who swam outside once a week
- They found that the men had lower pulse rates and lower blood pressure.
- Outdoor swimming is becoming increasingly popular in both the UK and Denmark
Swimming outside in winter can help burn more calories.
One study found that people who regularly jump in cold water, such as swimming in the ocean or lakes, use more energy when they feel cold, which may help with weight loss.
The calories seem to be burning because their skin temperature rises more quickly than those who don’t go wild swimming.
The evidence comes from a small study of eight men who took winter swimming two or three times a week, before going to a heated sauna—the Scandinavian version of wild swimming.
They were compared to eight men of similar age and weight.
Swimming outside in winter helps the body adjust to colder climates, claims a study today (stock)
The results showed that men who swam in cold water burned on average about 500 extra calories per 24 hours compared to other men.
This was measured by wrapping them in a cold blanket and measuring their response.
Dr Camilla Scheele, senior author of the study from the University of Copenhagen, said: ‘Our results suggest that people who swim in cold water train their bodies to deal with cold temperatures differently.
How does the body react to cold?
The human body lives at an average temperature of 37C (98.6F).
When it gets too cold a number of processes are started to raise the thermostat.
These include the constriction of blood vessels that flow near the surface of the skin — a process called vasoconstriction — to conserve heat.
There is also shivering to burn more energy and produce more heat.
The metabolism is also boosted to burn more energy, which further helps to raise the temperature.
Scientists have suggested that regular exposure to a cold setting may refine this system, and allow the body to adapt to the lower temperatures in the surrounding environment.
‘As they burn more calories, they are likely to lose weight, which can be good for their health in general, as obesity is a risk factor for many diseases.’
The study, published in the journal Cell Reports Medicine, found that men who swim or take a dip outside in winter have lower body temperatures.
This means that when they get cold, their bodies may have to work harder to warm up—just like someone without clothing, than someone in a winter jacket.
Brave souls who jumped into the cold water two or three times a week also had a healthy response to putting their hands in the cold water, which lowered their blood pressure.
Previous studies have suggested that people who allow themselves to cold burn calories by activating brown fat in their bodies.
This brown fat, which acts like a furnace and kicks to warm us, is a resource in the body, unlike white fat, which just stores calories and contributes to being overweight.
The new study did not find that winter swimmers burned more brown fat, but the authors suspect they may have started burning it earlier in response to colder temperatures.
The effect from cold blankets can be seen in studies of temperatures of around 20C in real life.
However the latest research suggests that spending time in a sauna, as well as wild swimming, may be necessary for the body to respond more healthily to changes in temperature.
More research is needed in more people, and in women as well as men.
The study’s first author, Susanna Soberg, from the University of Copenhagen, said: ‘Our results point to winter swimming as an activity that can increase energy expenditure, thus proposing a new lifestyle activity that may help reduce or reduce weight. can contribute to control.