For the very young, the very old, alcoholics and those with chronic heart and respiratory conditions, the current Washington weather is not only cold, but life-threatening.

The mechanisms used by the body to compensate for cold -- such as shivering, tightening of some blood vessels and release of certain hormones -- place stresses on vulnerable groups of people whose bodies may not be able to cope.

While no deaths from heart attacks have been verified during the cold wave -- perhaps because there has been little snow to shovel -- the death yesterday morning of a man identified as Bernard Ferguson, 50, of no fixed address, may have been caused by the freezing temperatures.

D.C. police found Ferguson in front of 35 E St. NW, and took him to the city's alcohol detoxification center, where he apparently collapsed before being moved to the Howard University Hospital emergency room.

"Our (body) thermomenter only went (as low as) 92, and it didn't even register," said Dr. Paul Cornely Jr., who led a team that worked on Ferguson for almost an hour before he died. An autopsy on Ferguson is scheduled today.

The cold is particularly dangerous to those who have been drinking heavily because alcohol dilates blood vesthe AAA. If the temperature drops to the skin where surface temperatures cool it. The cool blood then lowers the body's internal temperature.

One of the initial reactions to extreme cold is constriction of blood vessels in exposed skin and in hands and feet to prevent loss of heat through the skin.

Ironically, this can result in sacrificing the limb to save the life as hands and feet become colder because they are not being warmed by the usual blood supply. Frostbite may result.

Frostbite and frostnip are the two dangers faced by healthy adults on extremely cold days.

Frostnip is painful whitening of the tips of the nose, ears and fingers. Rubbing the affected areas usually returns them to normal. Frostbite, which actually kills cells in the affected area, is far more serious and varies greatly in degrees of severity.

An area of the body that is frostbitten changes from being hard, white and generally without feeling to blotchy red and painful when warmed. In more serious cases, the affected area may turn black, and gangrence may set in.

Doctors recommend treating frostbite by warming the affected area as rapidly as possible without burning it. The area should not be rubbed but placed in warm water or on a heating pad. Care should be taken not to overheat the water or pad because the area is usually numb and the patient may not be aware he is being burned.

The best way to combat the cold, experts say, is to wear several layers of loose, warm clothing that is water and wind repellent to contain heat and warmth. The head should always be covered, and gloves and shoes should always be loose enough to allow proper circulation.