DR. MICHAEL MOSLEY: How a cold shower can be good for you, but a cold snap can harm your heart

Just before Christmas I wrote about cold weather and pointed out that when it comes to health, the cold can have a positive impact.

Using frozen peas, or ice wrapped in a tea towel, is a great way to reduce inflammation if you’ve pulled a muscle, for example, and research shows that we sleep better when our bedrooms are a little cooler.

There are also health benefits to taking regular cold showers, such as boosting your immunity – and I mentioned studies showing that turning the thermostat down a few degrees can increase brown fat, a special type of fat that burns huge amounts of calories. generate heat.

But of course there is another, dark side to the kind of cold we are currently experiencing. Sudden cold snap can be extremely dangerous and lead to a sharp increase in deaths, especially from heart disease.

According to the British Heart Foundation, an extra 6,000 people die from heart disease every winter, but this is particularly noticeable in the days following a cold snap.

Taking cold showers regularly has health benefits, such as strengthening your immunity

A recent study conducted in Singapore (where it’s not exactly cold in winter), published in the journal Science of the Total Environment, found that a drop of just one degree in air temperature increases the risk of heart attack by 12 per day increases. cent, with people aged 65 and over particularly vulnerable.

So why is it that a drop in air temperature can have such devastating effects on the heart, while a cold shower or dip in cold water, which leads to a much more dramatic temperature change, seems to be beneficial?

Part of it has to do with the fact that the people who choose to take cold showers or take a cold dip are relatively fit to begin with; anyone who has existing heart disease should avoid it.

But they are also very different experiences. One of the first things that happens when you are immersed in cold water is that you begin to gasp for breath and the blood vessels in your skin, fingers, and toes constrict to retain your body heat.

This in turn causes your blood pressure to rise.

Shocked by the cold water, your body also releases the hormones adrenaline and cortisol, which increases your heart rate.

If you already have high blood pressure or heart disease, this additional burden can be dangerous. But if you are otherwise healthy, your body moves in the opposite direction when you step out of the cold water, causing your blood vessels to dilate, increasing blood flow to the skin and other organs.

That’s why you feel a wonderful warm glow afterwards.

If you continue to take cold showers, your body will adapt over time so you don’t get the same dramatic cold shock response. Studies suggest that adapting to the shock of cold water also improves our ability to cope with other stresses in our lives

And if you continue to take cold showers, your body will adapt over time so you don’t get the same dramatic cold shock response. Studies suggest that adapting to the shock of cold water also improves our ability to cope with other stresses in our lives.

However, during a cold wave, things are very different. You may initially have the same reaction to cold shock, but if your home is suddenly very cold, this is a shock that will continue and not something that will pass quickly.

In addition, over time the cold will cause your blood to become thicker and stickier (possibly because the body has to work harder to maintain core temperature, which directly affects blood flow), which in turn increases the risk on blood clots and strokes.

And that explains why hospitals typically see a sharp increase in stroke cases five days after the cold weather begins.

In addition, there is an increased risk of contracting flu or Covid during the winter months.

A study published last year from Keio University in Japan found that cold air and a rapid drop in air temperature were both linked to an increased risk of people contracting airborne viral infections.

The researchers think this is partly because exposure to cold can reduce the effectiveness of our immune system, but also because breathing in cold air (which retains less moisture than warm air) dries up the mucus in our noses.

And that’s important because mucus, along with the fine hairs lining our noses, acts as a first line of defense against invading microbes. Getting a respiratory infection will make you feel bad – and can be bad for your cardiovascular system, as viruses like the flu and Covid damage the lining of your blood vessels, which can in turn lead to blood clots, ‘leaky’ blood vessels and reduced blood flow to your heart and other organs.

During the winter months there is an increased risk of catching the flu or Covid. A study published last year from Keio University in Japan found that cold air and a rapid drop in air temperature were both linked to an increased risk of people contracting airborne viral infections.

Research has also shown that if you have heart disease and get the flu, you are almost ten times more likely to have a heart attack.

So if you are over 65 or in a risk group, I recommend you get a Covid and flu shot (I’ve had both) and of course dress warmly.

If you go outside, you may want to wrap a scarf around your face to protect your airways and keep your mucus from drying up.

And if you’re vulnerable and going somewhere crowded, consider wearing a mask.

Finally, when it comes to keeping your immune system in good shape, don’t forget to take a vitamin D pill daily, eat a Mediterranean diet and try to get a good night’s sleep, as studies have shown that people who are chronically sleep deprived are three times more likely to get the flu if exposed to the virus than those who routinely get a good night’s sleep.

In a few weeks I’ll be writing a lot more about sleep and how to improve it in my new series appearing in the Daily Mail this Saturday.