Thermoregulation: Increasing Your Awareness Not Your Core Temp.

[Ironwood]

Hello
With the cold weather fast approaching I have been reading threads here and there about layering, staying cool and not overheating in the bush so I thought I would put together a thread that covers some things I have learned along the way. The articles are supposed to give you general knowledge about how the body works and what areas are vulnerable or key to this process. I don't recommend getting your body wet with cold water when in the bush. However just aerating these areas will help tremendously.

A while back a professional football trainer figured out that if he cooled the hands of his top performing players he could improve their performance during the second half of the game. His researched prompted the development of a hands cooling machine they would use when alternating the offense and defense.

Hands and temperature regulation

The hand is an ideal structure for high rates of heat exchange (gain and loss) due to its large surface to mass ratio, low metabolic heat production, large blood supply and rapid cooling rates. Specialised blood vessels within the hand control the rate of blood flow and are very sensitive to changes in the environment and core temperature. For example, on a cold day the blood vessels near your skin constrict and divert the warm blood to your central organs. However, when you are getting hotter, blood will flow to your skin and coupled with sweat responses will help you to cool you down.
Hand cooling

The idea of hand cooling to aid thermoregulation was introduced by the Royal Navy in the late 1990s. The first study conducted by Navy researchers aimed to quickly reduce heat strain by immersing hands in cold water following exercise in 40°C heat whilst wearing full fire fighting clothing(1). After exercise the participants rested with their hands in water maintained at 10°C, 20°C, 30°C or were rested without hand immersion.
The results showed that the colder the water, the quicker the rate of cooling. After 20 minutes of recovery, core temperature had decreased from 38.5°C to 36.9°C in the 10°C water and to 37.3°C and 37.8°C in the 20°C and 30°C water respectively. The authors concluded that this simple technique could be applied to many industrial and military tasks where personnel alternate between work and rest for extended periods of time.

Alternating between work and rest is a feature of many sports. Building upon previous military research, researchers investigated the effects of hand cooling by immersing hands in 10°C cooled water during a 10-min recovery period from a 60-min exercise bout on subsequent high-intensity time trials at 30°C and 60% humidity(2). .

When our body temperature drifts only a couple of degrees above or below normal, our mental and physical performance becomes impaired. Even modest rises in body temperature cause fatigue and exhaustion, issues of concern in hospitals, on the battlefield, and in sports. Professor Heller and his colleagues have found that removing heat from an athlete’s hands results in an increase of double or triple the rate of conditioning that might otherwise be expected. At the other end of the spectrum, some elderly people, those exposed too long to very cold weather, and patients with certain diseases may be unable to maintain normal levels of heat in their bodies. Professor Heller’s lab has created a “glove” that can quickly extract or insert heat in our bodies, which offers the potential for some amazing improvements in human performance, well being and comfort.

Similar to the hands, there are other spots on the human body that are generators of heat these are spots where the blood flow is more significant

Get Acquainted With Your Body's Pulse Points

The reason this remedy works is because your wrist and neck both contain pulse points—essentially, areas where you can feel your pulse because your blood vessels are close to the surface of your skin. Because they are so close, however, you can also cool off your blood and body temperature by getting the area in contact with cool water.

However, your neck and wrists are not the only pulse points on your body (though your neck is arguably one of the most effective). The insides of your elbows and knees are two other common pressure points, as well as the tops of your feet and insides of your ankle (near the area where your ankle bone sticks out). There's also a pulse point on your inner thighs. And, while the forehead is commonly used as a cooling spot, the pulse point on your head is actually closer to your temple and the area just in front of your ear. There are a few more, of course, but these are the most convenient for the purpose of cooling yourself.
Adjust Your Cooling Method to Your Activity

Obviously, not all of these pulse points are going to be convenient to cool down all the time. There are a number of different ways you can go about cooling them down, and you'll need to use the ones most convenient to you at the time. For example, if you're out exercising in the heat, wrapping a damp bandanna (or better yet, a specialized homemade cooling scarf) around your wrist, elbow, or neck (when you can) is an easy way to keep cool.

Some recommend putting the towel-wrapped ice on your pulse points for a minute at a time, but there isn't a ton of consensus on the subject—just do what feels comfortable for you, and make sure it's "cool" and not cold. Don't use just ice; make sure it's wrapped in a towel or something similar (the same rules apply to the water-soaked scarf as well; cool, not cold).

These tips come from the bicycle rider population but the principles are the same as when huffin' it through the bush.

1. Wear less clothes

Lots of times, you actually need less clothes than you think. Still go in layers, but you actually want to be on the chilly side when you start. If you are warm enough from your clothes when you are first riding on a chilly day, in no time at all you'll be too hot and have to peel off layers. If being chilly when you first start makes you nervous about never warming up, you can always throw a jacket or sweater in your pack to use if necessary.

2. Make minor adjustments by removing hat or gloves

If you find yourself getting warm when you're riding, you’ll find that relatively small steps may be all you need to cool off. Removing a hat or pair of gloves as you ride is often all it takes to go from starting to feel hot and sweaty to giving yourself enough breeze and ventilation to be cool and comfortable.

3. Use ventilation features in clothing

Many clothes (regular or cycling specific) offer features that can help cool you off. Lower the zipper in the front of your jacket or sweater to let cool air into your torso area and to allow warm air to escape. Or, if you're wearing a windbreaker, undo the vents under the arms that many have, or else just roll your sleeves up.

4. Drink lots of liquids

On cool days, it's easy to lose sight of the need to stay hydrated. If you continue to push fluids, not only will you keep your body satisfied for its normal hydration needs, but the cooler liquid will help lower your body temperature.

5. Use layers effectively

Certainly you can experience fairly dramatic temperature changes just in the course of an hour in a single ride. Your exertion levels will vary, the external air temperature will change as you ascend hills or descend into valleys. The sun will shine brightly or be covered by clouds. Most important is to have several different options for how you dress, between head and hand coverings and a couple of different layers for your torso -- either a jacket, sweater, windbreaker or vest -- and to be aware of your own body's temperature and to add or take away as you either heat up or cool down over the course of a ride.

This and other articles point out the importance of accessory articles of clothing, like hat, gloves, bellacluvas, scarfs, or ear muffs when it comes to regulation of body temp. Adding or removing these articles that cover major pulse points will really aid in keeping temps up or down depending on your current state.

When bushcrafting with a heavey load, through the snow or over rough elevated terrain, you should be thinking more like a cross country skier as far as dressing working up a lather of sweat. You should probably start out on the cooler side of your clothing choices as "work" represents heat generation. You will heat up as you travel, and knowing this ahead of time will prevent that first on set of uncomfortable sweat.
This is why I like accessories like, hoods, stocking hats, scarf, mittens, bellacluva and a lite packable windproof shell. They are small, light weight items that can really help regulate. Carrying these kinds of items will allow you to wear less on your main trunk and body while helping to regulate your internal core temp better.

Good luck and hope this helps improve your comfort levels in the bush.
happy trails
phil

http://en.wikipedia.org/wiki/Thermoregulation
http://oso.stanford.edu/lectures/7-cool-hands-better-performance
http://www.pponline.co.uk/encyc/physiology-in-sport-keeping-your-hands-cool-can-help-your-performance-42449