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The first real snow storm of the winter (not counting the freak pre-Halloween storm) finally hit upstate New York late last week. I hope you all heeded my words from last week's Part 1 to this blog and spent some time outside to re-energize and burn extra calories. I'm joking- I hope you all stayed safe and warm. The worst part about snow storms is that I'm too old for snow days!
What winter means to me. Image Credit: worldofvieta.tumblr.com
This week is part 2- The Dangers Of Being Cold
(I will try to remain unbiased as I present this part of the blog)
Humans aren't built to live in a cold environment. To survive in cold weather, enough body heat needs to be generated by burning appropriate food and that heat needs to be trapped by suitable clothing and shelter. When a normal person starts to feel cold, usually around 25°C or 77°F, physiological responses such as shivering and diverting blood away from the extremities kick in. Nerve cells that transmit impulses work slower in the cold which is why it's more difficult to fix the zipper or button on your coat. Your blood vessels also constrict, increasing blood pressure. In order to adjust, your body reduces fluid volume by getting rid of water in urine (So from what I understand: you have a racing heart, cold fingers that can't work zippers, and you have to go to the bathroom. I'm starting to feel justified).
Dehydration
You can still sweat when it's cold outside, especially when you overdress in an attempt to stay warm. Fluid is also lost through humidified breath in cold weather and the body produces less concentrated urine. These factors can all lead to dehydration. Dehydration can impair your body's ability to retain heat as well as cause headaches, cramps and elevated heart rate. It's important to continue to drink fluid while working or exercising in the cold. But don't eat snow, it will drop your body's core temperature and extra energy will be used to keep warm.
Frostbite and Hypothermia
The maintenance of body temperature becomes difficult when the air is moving or damp. Wind chill can dramatically reduce the time it takes for skin damage to occur. For instance, in calm conditions at -29°C (-20°F) a well clothed person is in little danger, but a light wind of 10 mph gives the same effect as a temperature of -44°C (-47°F ). At this temperature exposed flesh can freeze in a minute or so.
Image Credit: manfredkaiser.com
Frost nip is a precursor to frostbite. Frost nip is caused by lack of blood flow to parts of the body, such as end of the nose, tops of ears or fingers, because they are losing too much heat. It can freeze the surface layers of the skin and lead to symptoms like those of a sun burn. Although there is no permanent damage, if left unattended it will lead to frostbite.
 Blood circulation in cold weather. Image Credit: Harvard Health
Frostbite means that skin has fallen below freezing and ice crystals form within the live cells of the skin, killing them in the process. When the area is rewarmed, it swells, blisters, and turns blue-purple to black. It then forms a hardened black carapace. If you're lucky, the dead layer with fall off and new skin will replace it, but it's painful. If you're not so lucky, the frostbite will affect the deeper layers of muscle and bone. This usually results in permanent damage or amputation.
Shivering is an involuntary movement used to create heat. Extreme shivering can increase heat production by up to five times but this function also requires high-energy foods and can divert blood away from the core causing heat loss to accelerate. Hypothermia sets in when the body loses heat faster than is produces it. When the body temperature falls below 78°F, death is likely. There are two types of hypothermia: acute and chronic. Acute is caused by sudden immersion in cold water. Cold water can cool the body 25 times faster than air. Chronic hypothermia can develop with exposures of 12 hours to several days.
Flu and High Blood Pressure
Cold weather and respiratory disease go hand in hand. The flu virus thrives in dry, colder temperatures and there is also evidence that the cold suppresses the immune system. Research suggests that cold weather increases the systolic blood pressure significantly in those 80 and older.
BUT, the common cold is NOT linked to being cold! (Oh what our mother's would say)
What does this lead to?
Due to conditions such as hypothermia, influenza and pneumonia, the mortality rate is about 15% higher than on a summer day. There are also indirect factors that lead to deaths such as injury from falls, accidents, carbon monoxide poisoning and house fires. These events can all be to cold conditions. Cold hands and feet could mean less coordination, less feeling and less motor control. This means that you could be clumsier and accidentally hurt yourself, especially since there is also a decrease in flexibility leading to a higher risk of strain injuries. There are some ideas that up to 70% of the wintertime deaths can be traced back to heart attacks, strokes and other cardiovascular causes of death.
Who is the most at risk?
Non-white elderly men are the most at risk, while white women are the least at risk. I'm almost always complaining about having cold hands and feet and it turns out that it's because women have a higher gradient of temperature from the skin to the body core and a higher level of subcutaneous fat. This means that women are more able to maintain a constant body core temperature in cold conditions even though they are more at risk for frost bite in their extremities.
 Since your body keeps heat around the heart and brain, wear a hat to keep the heat from escaping.
While the sex and race of a person is important to understanding their susceptibility to cold, age has the highest influence. Elderly people are the most at risk for injury or death from cold. This is most likely due to shivering and vasoconstriction to reduce blood to the appendages.
Adaptation helps too. Those who live in colder cities and parts of the world have a higher tolerance for what "cold" means because their metabolism changes to adapt.
So there you have it, the good and the bad about the winter time and being cold. Whether you decide to venture outside for some winter time exercise or stay inside with a good book, please remember to stay safe and warm this season.
Resources
Out in the cold
How Humans Deal With and Survive Extreme Cold
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Re: How Cold Affects You- Part 2
