jueves, 25 de marzo de 2010

CLOTHING FOR COLD WEATHER

As described in the layering approach entry, start with an inner layer of lightweight clothing, for example a polyester jersey and spandex shorts. Think of these "warm weather" clothes as your cold weather underwear. You will probably be carrying them anyway, so why not use them? Over them might go a long sleeve thermal shirt and thermal pants. Together, these layers would be your first defense against cold. Then depending on ambient temperature and wind chill factor, you could put on the breathable shell jacket and pants for added warmth and wind protection. If the day is colder still, you could wear two thermal shirts and pants. And although the insulated jacket is useful mainly at the rest stops, still you could wear it while cycling if necessary. And once again, make good use of your hat and mittens.

Depending on your cycling style and the ambient conditions, you will need to experiment with your cycling wardrobe to determine waht works best for you. The advice is to carry plenty of layering garments, but to be careful not to wear too much while cycling. Pay strict attention to your microclimate.

WEARING CLOTHING DYNAMICALLY

Rather than ignore the cold, or the sweat, we can play a more active role in regulating body temperature. We adopt the layering approach, as described in other entry in this blog, donning a layer the moment we begin to feel a chill, and removing a layer (and possibly slowing the pace) at the first hint of sweat.

Better yet, we learn to anticipate the condition and make the appropiate adjustments ahead of time. For example, suppose we are facing a long, steep climb, one that is sure to get us sweating. We remove a layer of clothing before commencing the ascent. When approaching a long descent, we anticipate the inevitable cool-down by donning another layer of clothing, and posibly by picking up the pace jut a bit. (However, when not going downhill, a moderate pace in cold weather produces the best flow of long term energy).

In a way, anticipating the conditions is like balancing a yardstick on a finger. Until we learn to anticipate the stick's leaning, our corrections will alway come too late, so they will have to be more drastic. But when we learn to make the corrections in advance, they will need to be only subtle.

Our heads radiate away a fair portion of body heat. So if we begin to feel chilled we put on a warming hat. Feeling too warm, we want to increase heat radiation, so we remove the hat. This is a very effective way to make small, easy adjustments.

In cold weather the hands also act as radiators, due to the relatively large surface area of the fingers. If your hands feel hot, remove your mittens and your hands will cool quickly. But since the blood circulation in the finger and hands is not great, you must be careful not to let them become cold. Otherwise they will be very slow to warm on their own. This means that even on a moderately chilly day you may want to wear at least a thin pair of mittens.

OUR MICROCLIMATE

In cold weather our clothes create a microclimate next to our skin that is much warmer than the external ambient conditions. We produce this warmth metabolically and we retain it with clothing. And while our eyes see the chilly, external environment, our bodies "see" the warm microclimate adjacent to our skin. And because we tend to be sight oriented rather than skin oriented, we see our needs for clothing, rather than feel them. As a result, we tend to overprotect ourselves by piling on too much clothing for the ambient conditions. All is well while at rest, but while cycling we generate a great deal of metabolic warmth, and this, hampered by the excess of clothing, leads to sweating.

Sweat is the body's reaction to overheating. It i very effective at cooling our bodies, as long as the sweat can evaporate. Without evaporation there is no evaporative cooling.

So not only does the heavy clothing cause us to sweat, but the over-abundance of garments also prevents evaporation. And when the sweat fails to cool us, our bodies produce even more sweat.

This similar to throwing a blanket over a car's radiator. Even in cold weather the radiator needs to cool the engine to help dissipate the heat generated as a normal byproduct of work.

Cycling along on a cold day while perspiring inside excessive clothing -accepting the profuse sweat as an unavoidable part of the activity- is an extremely inefficient and dangerous way to travel. Not only are sweat-soaked garment uncomfortable, but they will be much less serviceable at the rest stops and at camp when needed most -when we are no longer producing an abundance of metabolic warmth. When at rest, we rely almost entirely on our clothing to keep us warm, yet those sweat-soaked garments will have lost a great deal of their ability to insulate.

This is why, in very cold weather, wearing too many clothes can be hazardous as not wearing enough. I consider this one of the most fundamental skills of cold weather cycling -body awareness in terms of our microclimate.

This relates not only to higher mileage bikers in frigid conditions. It applies to all bikers in chilly to cold weather. No matter the type of ride, be it an afternoon jaunt, a weekend climb journey, or a 10 day ride into the high country, when the temperature starts to drop, pay close attention to the microclimate and regulate it by wearing your clothing dynamically.

OPTIMUM COLOR

Often the tendency is to choose the color of our garments based on personal preference. But when we are cycling in various weather conditions, color plays a significant role in a garment's performance.

Solar radiation spectrum is composed of heat, UV rays type A, B and C; infrared rays, visible light rays, microwaves, X rays, gamma rays, and many other types of radiation of different wave lengths and frequencies.

Light colored clothing blocks solar radiation better, meaning that it absorbs less heat. Thi is extremely important when cycling under a hot sun, especially during the height of summer. Light colors also radiate less heat away, helping us stay warmer on cold, cloudy days and at night. And light colored clothing is les attractive to flying and biting insects. Ticks, which are generally brown, are more conspicuos on lighter colored clothing.

Dark colored clothing absorbs more solar heat, and this works againt us on a hot, sunny day. On a cold, sunny day, the dark color may generate needed warmth, but only for the parts of our body facing the sun. That same dark clothing will radiate valuable body heat on the shaded side of us. However because dark clothing is again a good radiator of heat, we can use it in hot, shaded regions, al least when we need to cover ourselves fully because of mosquitoes or biting flies.

If only one color is to choose, it would be a light one, since most of the cycling is made in sunhine.

Regarding the UV protective performance of clothing's color the dark ones like black, green, blue and beige are the most efficient. Blue is the best.

CLOTHING FOR HOT WEATHER

Ideally, the hotter the day, the more ventilation our skin needs. And even thin clothing restricts ventilation, especially when sweat dampened. Meaning that the less clothing we wear in hot weather the better -not just for comfort but for our well being.

But hot weather is frequently associated with strong sunshine and this means a high level of UV radiation too. So our needs of clothing for hot weather include protection against the UV rays from the sun light.

In very hot and sunny weather we recommend to wear a loose fit well ventilated long sleeve light polyester jersey and cycling shorts. The long sleeves protect your arms' skin from hours of exposure to the UV radiation. The loose fit design and ventilated fabric ensures adequate ventilation and permits a layer of fresh air circulating over your skin.

During your rides the key is to protect the parts of your skin exposed long hours to the sun radiation . A good approach is to attach a piece of fabric big enough to the edge of your helmet to cover your ears and neck.

COTTON AND HYPOTHERMIA

The ubiquitous cotton T-shirt. Comfotable when clean, rather less so when dirty, and very slow to dry even in warm weather. In fact, the cotton T-shirt is so slow to dry that the biker usually does not bother washing it. And with the passing of days and weeks, as the shirt grows ever more soiled and odiferous, it begins acting as a people repellant and attractant for other living species.

On a cold day, when cotton becomes wet -from sweat for example- it can sap vital body heat. Cotton fibers are hydrophilic, meaning that they absorb moisture. This is why the biker who wears cotton, and who sweat-soaks those garments in cold weather, will be socializing with hypothermia at every rest stop. Even as little as one percent cotton in a garment is unfavorable.

Certain synthetics (like polyester and polypropylene) are hydrophobic, meaning that the individual fibers do not absorb moisture appreciably. (Nylon is fractionally absortive, making it somewhat slower drying than the true hydrophobics. This is why the cycling jerseys must be polyester and polypropylene or Thermax, rather than nylon). Any synthetic garment is as cold as a cotton one when wet. However, the synthetics are faster drying; so in essence they are much more forgiving, which helps explain their popularity in today's outdoor apparel.

People sometimes experience reactions to synthetic fabrics. Generally, the fibers themselves are inert, but some of the chemicals added to them can cause sensitivities. Which is not to infer that cotton garments are chemical-free either, by any means. But for most people, synthetic cycling garments offer the best performance, comfort and safety.