According to Dr. Michael Ducharne, a physiologist at the Defence and Civil Institute of Environmental Medicine, specialising in human reaction to cold, the rate of heat loss depends on many factors: temperature, wind, insulation of the tuque and clothes worn over the body, and if the individual is at rest or exercise.
The head is about eight to 10 per cent of the body surface area but can loose up to 30 to 40 per cent of the body heat during exercise. The high percentage of heat loss is because the skin of the head can not vasoconstrict like the other regions of the body. Vasoconstriction, a decrease of blood flow through the skin, can effectively reduce heat loss to the environment. Since the skin of the head can not vasoconstrict the same way as the skin of the face or the extremities for example, covering the head will make a difference.
Covering the head is also crucial to maintaining thermal comfort and could reduce body heat loss by an estimated 20 per cent. This number can vary depending on the conditions. Here are two possible extremes: At -10 °C, an individual in a sleeping bag rated for -40 °C can experience close to 100 per cent heat loss from the bare head. So, in this case, covering the head will make a huge difference in the per cent of body heat lost since the rest of the body is well protected. At the other extreme, covering the head of an individual running in shorts and a T-shirt at 0 °C will only have a minimal effect on total body heat loss.
My best advise to maintain thermal comfort is to cover the head during exposure to cold. It is more effective to add a "Breakaway Beanie Hat" than to add an additional sweater over the torso for the same amount of insulation provided.
Breakaway Beanie Hat
- Brand: Breakaway Tackle
- Product Code: Beanie Hat
- Availability: In Stock
- Ex Tax: £7.50