One of the greatest benchmarks of comfort when working or spending leisure time in the outdoor world is the degree of dry warmth you experience. All people are different in their warmth requirements - what may be okay for one person may be far too cold or hot for another. The clothing needed to maintain a comfortable average is happily readily available - but using it properly needs understanding in order to be effective.

Let's say that you are a hiker or rambler. I use this example from experience as I have been trudging around the UK countryside for years! However, the 'model' applies to whatever outdoor activity you take part in - hunting, fishing, hiking or just being a spectator at an outdoor event. However, any activity that requires varying physical effort - such as hiking - will produce the widest 'discomfort band' of all.

The reason is simple. Whilst walking along flat, level ground the level of effort remains fairly constant. Your body, a chemical engine, will convert its reserves to provide you with the 'cruising level' of energy needed to maintain this sustained, low-level effort. For this reason you will reach a median level of energy expenditure, part of which is converted to heat - which is why you become warm. As long as this effort remains constant, comfort is easily achieved.

Now a steep hill looms. Your body goes into 'bottom gear' as you lift your body weight against gravity to conquer the slope. The energy demands on your body rise dramatically and far more heat is produced. If your body can't dissipate that heat - you get hot. It's as simple as that.

Your body has one aim in mind: to keep your core temperature at a steady 98.6 degrees F. (37 degrees C.). It has two main methods of regulating this temperature - perspiration to cool and shivering to warm. Either method can be a cause of discomfort, so it seems logical that, if possible, you should aid your body in its attempts to maintain a comfortable temperature. Now, unless you sit still in a chair all day this ideal temperature will fluctuate. You're not likely to notice much change much in everyday situations, but outdoor activity is different. So how do you cope with the problem?

The answer is a principle called 'layering'. It works on the theory that several thin layers are more flexible - in terms of temperature control - than one thick layer. An ideal layering system would consist of a light, thin 'fleece' or insulating shirt (lower body garments can be added for colder conditions), then a lightweight insulating and windproof jacket, then a waterproof and 'breathable' outer shell garment. The inner garment is, in some ways, the most important. When purchasing such a garment, ensure that it possesses excellent 'wicking' properties - that is, it will transport perspiration away from the skin effectively. This is essential. Perspiration left on the skin can cause rapid chilling that can be very uncomfortable indeed! The three-layer effect ensures that layers can be removed or added very quickly in order to maintain a comfortable body temperature.

Layering garments are available from all good outdoor clothing stores and the staff are generally knowledgeable - if they aren't, go elsewhere! Layering is without doubt the finest way to maintain comfort in normal to cold conditions. Real arctic conditions are beyond the scope of this article and specialist advice should be sought if you're planning expeditions in these areas.

A last word about totally waterproof jackets. Yes, they will keep the water out - which is not the same as keeping you dry, especially if, like myself, you 'run hot' when hiking. No jacket can change a physiological response - if the humidity and water/air saturation outside the jacket exceeds the conditions next to your body, you'll still get wet - but from your own perspiration! Therefore, the more 'breathable' the jacket material the more comfortable you will be - even if a little rain does get through!

In closing, I would advise anyone who plans to start outdoor activities to pay attention to the clothing required - the method outlined above really can make the difference between a pleasurable experience and one you would rather forget!