Throughout history, people have had to find ways to cope with varying environmental conditions. Whether they lived in a hot or cold climate or had access to plentiful or limited water, they adapted their clothing and their homes to the conditions around them. With the advent of technology, we gained the ability to heat and cool our houses year-round, and to transport and purify water, making it easier for people to live in settings such as the American Southwest, that were previously inhospitable. As an inhabitant of Texas, I frequently comment that I don’t know how people lived here before the advent of air conditioning and refrigeration.
Certainly, we all spend time tracking the weather via our own senses, thermometers, and reports we find on television and the internet. We speak knowledgeably about what the latest radar images show, and how changing weather patterns may impact our communities. But few of us stop to think how our body measures, regulates, or maintains our own temperature or how our body temperature impacts our physical and Mental health.
A small structure in the brain, the hypothalamus, is responsible for regulating a number of homeostatic processes including food and fluid intake and our body temperature. A component of the hypothalamus called the preoptic area is thought to be responsible for setting and maintaining our ambient body temperature around 98.6 degrees Fahrenheit. Thermoreceptors located in the skin, the spinal cord, and our internal organs relay signals to the hypothalamus regarding our body temperature and the hypothalamus initiates cellular and behavioral signals to maintain the set point. If we are too warm, we can reduce heat by sweating, and if we are too cold, we shiver to generate warmth. Of course, we can also take behavioral steps including removing clothing or exercising to regulate our temperature.
But those are temporary responses to mild fluctuations in our body temperature. Humans, like all mammals, are constantly generating heat through a process called thermogenesis. Adipose tissues (fat cells) generate warmth through a complex chemical process that releases heat. Hypothermia occurs when the body is losing more heat than it can generate. If our extremities get cold, ice crystals can form, causing tissue damage colloquially called frostbite. Prolonged hypothermia can result in reduced blood pressure, decreased heart rate, pulmonary congestion, cognitive function decline, and ultimately cardiorespiratory failure and death.
The Importance of Water Regulation
Another important part of maintaining body temperature and chemical balance is the regulation of water intake. When we are adequately hydrated there is enough water to maintain our blood pressure, cerebrospinal fluid, the balance of liquid and salt in our body and to sweat to cool ourselves. When we aren’t taking in enough water the hypothalamus activates a chain of hormonal signals that trigger thirst and regulate the distribution of water, we do have available. When people overexert themselves in warm weather and don’t compensate by replenishing their water and salt levels, they can have difficulty sweating and cooling themselves. If your body temperature gets too high, it can be fatal.
Ironically, our hypothalamus may deliberately raise our body temperature when we are sick to create an internal temperature that is inhospitable to invaders such as bacteria and viruses, which themselves are temperature sensitive. A high body temperature can also impair our cognition and ultimately damage organs including the kidneys, the heart, and the brain.
It is more difficult to determine how external and internal body temperatures impact our mood and ability to think clearly. There is some evidence that warm weather exacerbates Mental health conditions based on large-scale studies of hospital admissions, but this is hard to quantify on an individual level. Research suggests that people tend to become more irritable and stressed when the temperature gets warmer, but this is also a function of resources and expectations. Some people seem to thrive in hot desert climates, while others actively seek colder environments. It is clear that if weather conditions impact our ability to sleep comfortably it impacts our well-being, but again that will depend on individual factors such as how warm or cool we can keep our homes.
The bottom line, though, is that talking about the weather isn’t simply a way to kill time. Our very ability to survive depends on managing our body temperature. So maybe we should all spend a little more time helping our hypothalamus to maintain our fluid levels and body temperature at optimal levels. When the weather is warm, we need to regulate our sun exposure, water intake, and activity levels and when it is cold, we need to be sure to cover exposed skin surfaces and to keep moving to enhance blood flow. Doing so makes us more comfortable but also reduces the amount of energy our body needs to spend on temperature regulation. That in turn can give us the energy we need to focus on other aspects of our physical and mental well-being.
