How Temperature ACTUALLY Affects Immunity
If you’ve ever wondered how temperature affects immunity, you’re not alone. There is so much conflicting “evidence” swirling around the internet that it can give you a headache just sifting through it all. Does cold weather cause you to catch a cold? Are you healthier and safer from the flu when it’s warm out?
While cold and flu season tends to happen when the weather drops, there is so much more to it than just winter weather. Temperature can affect the body in many ways. In terms of the immune system, it does play a role, but temperature is not nearly as big as factors like what you eat or how much you move. That said, temperature changes can affect your health and how well your body fights pathogens such as the cold and flu. But how does temperature affect immunity? Read on to find out.
Does cold weather make you sick?
Many people believe that cold weather, in and of itself, is what causes people to get sick. That’s not necessarily true. The weather, specifically cold temperatures, isn’t always to blame for increased sick days and sniffling noses – not directly, anyway. People are more likely to get sick during colder months because of the environment in which viruses thrive.
Take the rhinovirus, for example. It’s the germ that causes the common cold. While many people get a cold around the same time each year, it’s not due to the temperature outside. Instead, it’s because when it’s chillier outside, the virus can duplicate more effectively, since it thrives when the air is colder than our body temperature.
However, the nose cavity, a common breeding ground for viruses, almost always sits below body temperature. So that doesn’t completely explain the cold weather connection.
The connection between colder temperatures and illness
Research has examined how viruses are more likely to cause illness in cold weather and found that lower temperatures and humidity do play a role. One specific study looked at higher vs. lower temperatures and rhinovirus infections. People participating in the study were more likely to get ill when the temperatures decreased. So, from these results, it seems that people do get sicker when the temperatures drop.
One other aspect of cold and flu season that relates to the cold is transmission. To become infected and sick, someone must first contract the virus. In cold and dry temperatures, it is much easier for that to happen. This is because that kind of climate makes it easier for the virus to get from person to person.
It isn’t just the virus and cold temperatures that make spreading infection easy, though. In winter, people are much more likely to spend time indoors with others who may be ill than they are in warmer, more outdoorsy months.
Does temperature change weaken immune system function?
Cold weather may aid in virus transmission and survivability, but there is still some question about whether the immune system suffers simply because you forgot your jacket. The answer isn’t as straightforward as you might think.
Some evidence suggests that cold weather can hinder your body’s ability to fight infection because it affects the immune response. One specific research study examined the effects of lower temperatures on the immune response of mice with rhinovirus. The results showed that the mice exposed to dropping temperatures were less ready to battle the infection. That said, the study was conducted on mice, not people, so doesn’t exactly paint the whole picture when it comes to human health.
Can cold weather increase immune function?
If you’ve heard of any of the cold weather health fads of recent years, such as ice swimming or cold shots, you know that people seem to think exposure to frigid temperatures can boost the immune system. While these practices are certainly more extreme than walking from your house to your car in blistering weather, they hold some scientific weight.
One specific study examined the immune system of people exposed to cold temperatures and found that repeated immersion in freezing cold water caused stress in the body. That stress jumpstarted the immune system, increased the metabolic rate, and elevated levels of neurotransmitters known as catecholamines. These three actions caused a slight boost in immunity.
Does heat stimulate the immune system?
Looking at things from the opposite end, we might assume that heat can improve immunity. But does the immune system work better at higher temperatures? Well – it’s complicated.
The body itself heats up when a virus or other pathogen is present; that’s what a fever is. Your body raises its temperature in the hopes of making itself less habitable for the germ that’s taken root. A fever is also the body’s way of destroying any virus or bacteria that aims to cause it harm.
Hot temperatures may also strengthen the immune system, but research isn’t as comprehensive on that subject. That’s because the body self-regulates in high temperatures to remain at its healthiest heat level. This means the only authentic way to improve your body’s ability to fight infection through heat is by raising your core temperature, and your environment alone will usually fail to do so.
The only caveat is when core temperature rises because of extreme heat. Still, in that instance, the body begins to protect itself by slowing processes down as a form of self-preservation. When that happens, you can develop unwanted symptoms such as fatigue.
So, to sum up: while cold weather can make you more susceptible to illness, it isn’t quite the significant factor that many think it is when it comes to catching more colds in the winter months.