Why do We Shiver?

The human body has many amazing systems that help keep us running smoothly through various conditions. Our body has homeostatic functions that automatically monitor, adjust and regulate our important systems without our even knowing it. Breathing, heart rate, weight regulation and blood pressure are all regulated subconsciously. Shivering is just one of these homeostatic functions our body employs to regulate our body temperature. Also called thermoregulatory shivering, we shiver in an effort to keep ourselves warm.

Our brain both consciously and subconsciously detects cold simultaneously through different sensory systems, which prompts the body to shiver — the sensory system that prompts the shiver isn’t the same as our conscious detection of cold. Our body attempts to maintain our core temperature of 98.6 degrees Fahrenheit (37 degrees C), despite ambient temperature. In an attempt to avoid hypothermia where our body temperature is lowered to dangerous levels, our muscles are prompted to contract and expand quickly, resulting in a shiver. This in turn produces more heat in the skeletal muscles to provide extra warmth to our organs. It does use a lot of energy, and severe shivering is a last resort in an attempt to stay warm. Along with shivering, your teeth may chatter due to tightening jaw muscles.

In some cases, we shiver after having anesthesia, because the drugs and medication affects the body’s ability to regulate our temperature. This may result in a drop in our core body temperature, and we shiver to compensate. It is usually a transitory side affect, and should resolve in less than an hour.

Those suffering with a fever may also shiver and shake with chills. Although they may have a temperature above 98.6 degrees, the “set point” of the body’s temperature has been raised by the brain by the onset of a fever. This prompts the body to do things to make it warmer. Shivering when you have a fever creates more heat as it would in the cold, thus, elevating your body’s temperature even more.

Shivering is just another way our body works to maintain itself — take it as a clue to get out of the cold or add another layer. Remember also that as we age, our sensory systems have a decreased ability to identify changes in temperature and respond accordingly. Elderly people should rely less on our body’s automatic response systems, and more on common sense in extreme cold, or heat.