Four Ways of Improving Human Cold Hardiness

I’ve started a hardy (cold water) swim club in Owen Sound.
In relation to that I wanted to share what I’ve learned about keeping warm.

Here are various things you can do to improve your cold hardiness, or ability to stay warm when it is cold outside.

I will start with some of the most obvious and move toward the less well known, covering clothes, nutrition, physical hardy-making, and mental hardy-making.

Clothes

Clothes are essential for maintaining warmth. When it is cold, the body moves the warm blood to the core, leaving the extremities with relatively little.
So while it is important to insulate your core with several layers,
your feet, hands and ears are the most likely to be damaged by cold,
so they actually require some of the best insulation, boots, socks, gloves and ear-covering. Much heat is lost through the head as well, so a good hat always helps.

Also the location of the largest centre of brown-fat which generates heat from your white fat is near the clavicles, the bones near your neck. They are located there to warm the blood vessels going to your brain. This is why a scarf or other neck covering is essential for maintaining warmth.

Some people don’t like the look of winter clothing, or the sound of the waterproof layers rubbing against each other. It is possible to be warm and yet still be relatively fashionable by wearing a base-layer underneath, typically made from polar fleece. This does presume you wont be getting wet with snow, though a fleece base layer will help you stay warm even if you get damp.

Materials

The best insulation materials from nature are wool and fur, though being a vegan I prefer the synthetic ones. Polar-fleece even with a thin layer it is a good insulator, typically made out of polyester which does not absorb water, so may keep you warm even when damp. Faux fur can also be quite warm.

Fleece is good for base-layers, scarves, jackets, gloves, blankets.
Faux fur can be good for clothing that provides even more warmth.

Waterproofing layers can be good if you spend time in the snow, breathable ones being best, to allow for evaporation, keeping you the most dry.
Gloves and pants typically are where you’re most likely to need a waterproofing layer, though coats and hat as well if it is snowing.

Summary

cover extremities, use fleece, base-layers, water-proofing layers, and maybe faux fur.

Nutrition

Your metabolism which burns calories at a steady rate is largely what is responsible for the amount of heat your produce.

In order for it to functions correctly you need to have enough calories, so if you are nearing towards or are underweight, consider that to stay warm you will have to eat more calories during colder months, so there is something for your body to burn and turn into energy.

The thyroid is largely responsible for regulating the metabolism, and the nutrient which is essential to it’s functioning is Iodine. To get the bare-minimum you’d need to eat each day one of:
1. half a teaspoon of iodized salt (1tsp is max for salt per day).
2. 3 sheets of nori seaweed.
3. 1 teaspoon of dulse flakes.
4. 1 gram of kelp such as alaria or kombu.
If you were previously deficient, it is recommended to consume more than the minimum. Also generally the more iodine you have available, the warmer your thyroid can set itself. You can safely consume up to 10 times the minimum in iodine from non-salt sources.
from-source https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/

If you were considering eating more oily or fatty foods, the ones which are most beneficial are medium chain triglycerides, which can be converted into energy immediately, of those, lauric acid found mainly in coconut oil is the healthiest. While omega-3’s are also good for you to improve blood flow, the upper-intake for them is 3 grams per day, after which point there may be excessive blood flow.

Lastly another nutrient that you may find beneficial for hardiness is lecithin, which emulsifies oil and water, and is a building block of cell walls.

Summary

Eat enough healthy calories and seaweed to keep up your metabolism.

Physical Hardy-Making

Cold rooms, cold showers, cold dousing, and cold water swimming are all progressions of increasing human hardiness through physical means.

The body can adapt to the cold in numerous ways, including increasing the amount of brown-fat which burns white-fat to make heat, as well as as well as and increasing the number of blood vessels to help keep extremities warm as well as optimizing the pathways for heating the body.

Something as simple as turning down the thermostat at night can help you grow your brown-fat reserves from-source http://www.medicaldaily.com/cold-temperatures-help-brown-fat-good-fat-grow-stimulates-metabolic-balance-lower-blood-sugar-levels

Initially there is risk of “cold-shock response” which is when a person may reflexively gasp when entering cold water, this is mainly a problem in deep water, as in shallow water only air would be inhaled.
The cold-shock is followed by hyper-ventilation, which increases the amount of oxygen available to turn chemical energy into heat, helping you keep warm.

Also for people with underlying cardiovascular issues, jumping into deep cold water may be an issue, as it constricts blood-vessels and thus increases blood-pressure. Again it is mostly the shock that is an issue, as if done slowly the body and mind has time to adapt.

Once in the water, it is advisable to not stay for longer than 5-15 minutes, though many probably would want to leave the water much sooner, it is more of experienced persons not to overextend themselves.

Hypothermia is only a risk in 0 degree water after about half an hour, so risk is fairly minimal with only a 5 minute swim. Simply remember to have your towel and warm clothes ready after your swim, as the cold air outside blowing on a wet body can count towards that half-hour.

Summary

While being safe and getting enough iodine, regular exposure to cold will adapt you such as by increasing your brown-fat reserves.

Mental Hardy-Making

In addition to the above there are some forms of meditation and visualization that are used to improve internal heat generation.

Tumo Visualization

Some Tibetan Monks developed a form of meditation to help themselves stay warm. The gist of it is to visualize inhaling and exhaling flames, with flames burning in the belly. This activity is usually done when it is cold.

My theory is that it may work as a form of Pavlovian conditioning, where these particular thoughts are associated with increasing the metabolism and activating brown-fat reserves.

Drawing on some other studies that showed that concentrating on healing a scratch was more effective than not at healing it. It may be a useful visualization that is more direct, imagining your brown-fat reserves activating, as well as metabolism increasing.

Certain Tibetans also have a gene that adapts them to high-altitude living, it’s main symptom being a faster rate of breathing than normal in order to get sufficient oxygen out of the thin air. This may also work towards making Tumo an effective meditation in Tibet.

Breath of Fire Pranayama

Kundalini Yoga contains a form of controlled breathing called “Breath of Fire”, it is a very fast form of breathing, similar to hyperventilating.

Other than the increased metabolism from the fast paced activity, it can also increase the amount of oxygen available to system, which can react with available fats and sugars to generate heat.

Summary

Visualize your body warming itself, while breathing enough to let it burn your energy stores to warm you.

Concluding Notes

Personally I wear a t-shirt and shorts if I’m active outdoors above around 5C, and wear a shirt and pants if I’m idle for very long.
Though when biking under 10C if it is windy I wear ear protection and gloves.
Below freezing I wear layers, including t-shirt, shirt, sweater, scarf, hat and gloves.
Below -10C I usually opt to wear a winter coat or base layers.
If biking I also wear a balaclava and sunglasses.
Below -20C I wear everything.

So at just about any outdoor temperature it is quite possible to be warm and cozy.

When going winter swimming, if it is cold outside I bring extra layers than I would normally need, to warm up after swimming. Also hot tea and a carbohydrate rich snack like bread is nice.

Happy winter outings!

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