How Body Heat Is Lost And Saved

Your body looses heat in four ways: Conduction, Convection, Radiation and Evaporation. Heat always flows from a warm place to a cool place to seek a balance.

Example: Put an Ice cube in a glass of warm water. The heat in the water flows into the ice melting it, making the end result a glass full of water that is warmer than the ice was but cooler than the water was. If the flow of heat, on its path, encounters an area that is as warm or warmer than the area it came from the flow will slow, stop or reverse.

Conduction is a flow of heat from a warm object in direct contact with a cold object.

Examples: When you hold a cold can of beer you feel the heat in your hand flow to the can, and warm the beer, as a cold sensation. If you put the can of beer down the flow of heat from your hand will stop, and keep your beer colder. So, when you are seated in your kayak your butt will feel cold because the heat flowing from your body is warming the seat of your kayak. If you use a seat pad on your kayak made out of insulating foam rubber, you will slow the flow of heat from your body into the kayak.

Convection is the flow of heat from a warm object into a gas or liquid assisted by a circulation of that gas or liquid.

Examples: When a wind blows on your face you feel the heat leaving your face as it warms the air that is rushing past your skin. If the wind stops, or you cover up, you feel warmer. While swimming in chilly water, heat flows from your body into the water. If you stay very still the water around you warms up, but if you move through the water you leave a trail of warmed water behind you while you are moving into water that is cold and has yet to be warmed by your body heat.

Radiation is the flow of heat through the ether of empty space, like a beam if light. It is not necessarily dangerous nuclear radiation.

Examples: You are standing next to a campfire on a cold night. Heat is flowing from the fire, in a wave/particle beam, warming the side of you facing the fire, but the side of your body facing away from the fire is cold. If somebody stands in-between you and the fire they get the heat and leave you in the cold. When the sun is shinning you can feel its warmth; dark objects absorb this heat, while shinny or light colored objects reflect this heat. When the sun goes down every thing starts to cool off. You reach for your handy space blanket to wrap around you and it reflects the radiant heat coming from your body back to you.

Evaporation is the process of changing a liquid into a gas. In our case it is water. This process requires, and uses heat. It is facilitated by the flow of air.

Examples: While exercising you perspire; the moisture on your skin dries cooling your body. If you get caught in a rain shower with out a raincoat, your soaked clothing chills you even after the rain has stopped. If a wind picks up you are chilled even more. Once the clothing has dried, or you find shelter from the wind, you cease to feel cold.