It's hardly necessary to say that motorcycling entails a certain amount of risk.  If nothing else, the simple fact that a machine on which we're quite comfortable hurtling through miles of road that bring new meaning to the word "curve" cannot, when at rest, remain upright on its own should offer some hint.

Some risks, however, aren't quite as apparent as that pothole you narrowly avoided the last time you were in the wind or that driver who seemed intent on putting his car in the exact spot your motorcycle occupied while trying to change lanes and carry on a cell phone conversation at the same time.  For example, "on a slightly cool day (65° F, 18° C), a motorcyclist riding at highway speeds of 45 to 55 miles per hour (72 to 88 km/h) experiences a temperature equivalent of 33° F (1° C).  That's only one degree above freezing." (MSF 50-51)

The risk that I'm talking about here is hypothermia, a rapid decrease in core body temperature which can easily impair a rider's reflexes and ability to concentrate and react to changing traffic conditions.  Constant exposure to wind and weather makes motorcyclists especially susceptible to such changes in body temperature, even on days that would be considered "mild" in any other context.

Obviously, you're going to want to protect yourself from any potentially life-threatening condition by minimizing your exposure to risk, but in order to understand the tactics for protecting your body from hypothermia, you need to remember how the human heating and cooling system works.

The body "burns" food to generate heat and pumps warmed, oxygen-rich blood throughout its system.  Blood near the skin's surface gives off heat to the air.  The lungs absorb oxygen from the air and expel warm water vapor and carbon dioxide.  The body automatically adjusts blood pressure, heart rate, and breathing rate to maintain an almost constant temperature of the central core (the heart, lungs, kidneys, and other central organs) regardless of the outside air temperature.

If the core temperature begins to increase or decrease, the system quickly attempts to correct it.  A core temperature that is too cold creates a condition called hypothermia.  Only a couple of degrees below normal body temperature can be life threatening. (Hough 200)

When the body senses a drop in core temperature, its first response is to shut down blood flow to the extremities, starting with the fingers and toes (something we've all experienced as we've stomped feet and clapped hands to try and restore some feeling to numb hands and feet).  What isn't so obvious, though, is that the head is an extremity, too.  Large arteries along both sides of the neck carry warm blood to the head, so when the body's heating system decreases blood flow to the extremities, there's also less blood — and less oxygen — going to the brain. Ever felt sleepy after a ride in the cold? The bottom line is that as your body temperature decreases, your woozy brain may not be able to recognize what's happening. (Hough 200)

For motorcyclists, the hazard is that a chilled, oxygen-starved brain starts making mistakes.  At first, maybe it's just stopping the bike without putting a foot down or drifting off of the road onto the shoulder; however, ". . .in a hypothermic state, a rider can make serious or even fatal control errors, such as crossing the centerline. . ." or going wide into a turn and becoming uncomfortably intimate with the guard rail. (Hough 200)

One of the most important defenses a motorcyclist can employ against hypothermia is insulation of the head and neck.  The major blood flow to the head means it can radiate a lot of heat (up to 50% of total body heat can be lost through the head), unless it's insulated.  Insulating the neck slows down heat loss from those big arteries and provides warmer blood to the brain.  Neck insulation is vitally important to motorcyclists because our heads and necks are sticking out in the windstream.

How We Lose Heat To The Environment

The crushable EPS liner in DOT approved helmets is similar to a foam ice chest and helps insulate the head, but it's important to close off the gap between your collar and your helmet.  Whatever your choice of neck insulation — and definitely choose something, whether it be a scarf, turtleneck, balaclava, etc. — definitely don't leave home without it, even if the forecast calls for sunny skies with highs in the 60s (or teens Celsius).

Frequent rest breaks to warm up and refuel the body are another defense against hypothermia.  It's really not a bad idea to stop once every couple of hours (once every hour in really bad conditions) and get into a heated room.  Have a snack and drink one or two glasses of water.  Remember that the body burns food to produce heat and gives off water vapor during respiration, so you need to stoke up your internal furnace and rehydrate yourself.  Hot soup is good for cold rides because it provides both nourishment and liquid.  Coffee or tea is acceptable, but go through the body faster than plain water. (Hough 202)

When you take a break, remove or unzip enough outer insulation to allow your body to soak up room heat and move around to get the blood circulating to the extremities again.  Spend long enough inside to get warmed, refueled, rehydrated, and your body core cranking out heat again.  That may take half an hour or longer if you've spent a long time in the cold.  If you're still shivering, that's a sign that your body core temperature is still bordering on the cold side. You might need some additional warm-up time before hitting the road.

Shivering is actually a good sign in cold weather.  As body core temperature begins to decrease, the body begins to rapidly contract and expand muscles in an effort to generate more heat.  When shivering stops in cold conditions, you're in trouble.  You may start to feel very relaxed and peaceful, accompanied by a reduction in muscle coordination and judgment.  Other symptoms of hypothermia include irritability, slurred speech, loss of attention, lessening of pain, and stiff muscles.  The symptoms present themselves in a way similar to intoxication.

Hypothermia is not a something to be taken lightly; it is a life threatening condition.  If you or your riding buddies appear to be confused, can't seem to stay awake, or start making silly riding mistakes, hypothermia may be setting in.  When you recognize the symptoms of hypothermia in yourself or in others, take action.  The most important thing is to get yourself or your buddies off the road and into some place warm and dry as soon as possible.  If gradual warming and rehydration don't do the trick, or are not possible given the circumstances, get emergency assistance immediately. (Hough 202)

Now, I'm not saying that it's too risky to ride in cold conditions.  If you ride smart, the risk is very manageable.  By riding smart, I mean that if you're going to ride in the cold:

• Make sure your head is insulated.
  
  
• Make sure your neck is insulated.
  
  
• Dress in layers, starting with thermal underwear.  Make sure your layered clothing fits loosely to aid body heat in forming warm insulation.  If necessary, you can perform an impromptu strip show for your friends to get comfortable once you're indoors again; you might even earn a few extra bucks.
  
  
• Top off your layered clothing with a windproof outer layer to prevent cold air from reaching your body.

Jeans and a jacket don't cut it if the thermometer hasn't made it into the 70s (mid-twenties in Celsius) and you're planning on riding at highway speeds.  By taking the necessary precautions, you can keep a casual, cool weather ride from becoming a serious medical emergency.

Ride smart -- ride warm.

Article: Thumper

1. Hough, David.  Proficient Motorcycling: The Ultimate Guide to Riding Well.  Irvine CA: Bowtie P, 2000.
   
   
2. Motorcycle Safety Foundation.  Motorcycling Excellence: Skills, Knowledge, and Strategies for Riding Right.  North Conway NH: Whitehorse P, 1995.