In nature, winter is the culling season. Wild creatures that are old, sick, injured or malnourished often succumb to the harsh conditions; hypothermia, starvation and predation all take a toll. Early man also faced these threats as he emigrated from his tropical home to northern latitudes.
Most older humans will admit that their tolerance to cold weather has decreased with their advancing age and there are physiologic reasons for this perception. As we age our metabolic rate falls, our activity decreases, our calorie intake is reduced and our body fat begins to diminish; all of these factors make it more difficult to retain and generate heat. Furthermore, older persons often have chronic conditions that lead to impaired mobility and balance, making them more prone to falls and injury; the presence of snow and ice only exacerbates this risk. Finally, all of us are more likely to be infected with viruses during the colder months as our indoor lifestyle increases contact with other humans; many of these infections, including influenza, are more severe in the elderly and are more likely to be complicated by pneumonia, sepsis and other potentially fatal conditions.
Sensing all of these factors, older persons with financial resources tend to migrate to warmer climes for the winter months. While longevity is more related to genetics and healthy lifestyle choices, they know that they will be more comfortable in the warm environment. At some deeper level, we may also be experiencing the urge to return to our native ecosystem; we are, after all, a tropical species.
