frozen<\/span> but will turn red and blister when it thaws out. <\/p>\nThis is called superficial frostbite, as it affects the top layers of skin and tissue. <\/p>\n
It needs treatment, but it's not as severe as deep frostbite, which can cause damage beneath the skin to the tendons, muscles, nerves and bones.<\/p>\n
Skin becomes white, blue or blotchy and as it thaws, blood-filled blisters turn into thick black scabs.<\/p>\n
It's likely that tissue will die if the frostbite has progressed to this stage and the affected tissue may have to be removed to prevent infection, NHS guidance says. <\/p>\n
3. Blood clots <\/h2>\n
Not all cold-related health issues are caused by exposure to freezing temperatures; the temperature of your home as it gets chillier outside also matters. <\/p>\n
The UK Health Security Agency said "our bodies fight a constant battle" to keep our core temperature at around 37.5C cells and organs are protected from damage. <\/p>\n
It adds that when we start to get cold, our blood becomes thicker, which can lead to blood clotting – this is when it clumps together and hardens.<\/p>\n
Blood clots can be serious if not treated, leading to dangerous health events like strokes and heart attacks. <\/p>\n
In fact, the UKHSA said this "is one of the reasons we see more heart attacks and strokes in the days following colder weather".<\/p>\n
If you're able to, the agency recommended you heat your home or specific rooms you are using to "at least 18C". <\/p>\n
"This is the temperature at which we start to see changes in the body, when the blood starts to thicken," it explained. <\/p>\n
"So, temperatures above this are best to protect your health."<\/p>\n
Moving about rather than sitting still can also prevent your blood from clotting as well as keeping you a little warmer. <\/p>\n
Getting up at intervals to make yourself a warm drink or grab a snack is a good way to remember to keep moving. <\/p>\n
"If you can\u2019t move around, wiggle your toes and fingers," the UKHSA recommended. <\/p>\n
"It may not sound like much, but even small measures like this can help keep you warm and well."<\/p>\n
4. Breathing problems <\/h2>\n
Many us of keep our windows well shut throughout the day to keep the cold air out. <\/p>\n
You might think the nighttime is a good time crack open a window and air the place out, since you're tucked under your covers. <\/p>\n
But the Met Office warned that it's important to keep your house warm and your bedroom window closed on cold winter nights. <\/p>\n
"Breathing cold air can be bad for your health as it increases the risk of chest infections," it said. <\/p>\n
Asthma + Lung UK said cold air "can cause your airways to narrow, [increasing] the amount of mucus you produce and making it harder for you to breathe".<\/p>\n
"Cold, dry air can also irritate your airways and worsen symptoms like wheezing, coughing and breathlessness," it added. <\/p>\n
5. Lowered immunity <\/h2>\n
Being cold can also affect your body\u2019s ability to fight off infections, the UKHSA said. <\/p>\n
"This is why in the weeks after the cold weather we see more deaths from infections like pneumonia, and lung conditions and coughs can develop into a more serious problem," it explained. <\/p>\n
Asthma + Lung UK added that while cold air can make it harder to fight off respiratory infections like colds and flu, it's also the way we take refuge from the chillier weather that can put us at risk. <\/p>\n
Spending more time indoors can actually help spread respiratory infections, it said. <\/p>\n
6. Back pain <\/h2>\n
If you feel like your lower back pain feels worse when it's cold outside, you're not imagining it. <\/p>\n
Johns Hopkins Medicine said: "Back pain can indeed be related to barometric pressure and outdoor temperature. <\/p>\n
"Changes in pressure can sometimes cause pain in arthritic joints, including the spine."<\/p>\n
It added that your joints react to the environment, with the cold making them stiffer and more likely to suffer injury. <\/p>\n
Symptoms of a blood clot <\/h3>\n
There are two types of blood clots.<\/p>\n
A blood clot in one of the large veins in someone's leg or arm is called deep vein thrombosis (DVT).<\/p>\n
If not treated, DVT can move or break off and travel into the lungs.<\/p>\n
Meanwhile, a blood clot in the lung is called a pulmonary embolism (PE) – this can be deadly and requires immediate medical attention.<\/p>\n
Symptoms of a DVT include:<\/p>\n