All over the world, the seasons are a changin’. If you’re in the southern hemisphere like us, the days are getting shorter, darker, and colder. But if you call the north home then
you know nothing Jon Snow you can probably look forward to sunshine, Mojitos, and balmy evenings. No matter where in the world you are though, when the temperature changes, people tend to get sick.
Let’s cough it up and break it down: this is what’s happening on the inside.
In one highly complex experiment, researchers dunked healthy people’s feet in ice buckets and found they developed infections in their ‘upper respiratory tracts’ (in their noses, behind their noses, and in their nasal passages). So, it could be shown that cold temperatures make people catch a cold, but for ages, no one knew why.
Eight years later, another group of scientists studied the cold virus in mice and lab grown human cells. They specifically looked at what happened in cold vs warm conditions. At warmer temperatures, infected mice produced a burst of immune signals that fought off the virus. But at cooler temperatures, the mice produced fewer signals, and the infection lingered. Further, warm infected lab grown cells were more likely than cold ones to be killed off by the immune system.
The researchers theorised that when the temperature drops we start to breathe in colder air which chills our airways enough to suppress certain immune defences. In turn, a cold can take hold. Though the researchers claim that this is not the whole story, it seems to explain why our whole office got sick as soon as it got cold. We’re currently in autumn and falling like leaves. (See what we did there?)
The thing about spring: it’s warm, but there’s enough chill for a cold to take hold.
The air temperature at the start of spring might be warmer than what you experience throughout winter – but it’s still chilly. So what we described above can still happen in the spring. Plus, certain lifestyle factors unique to spring add to your chances of getting sick. For example, you’re more likely to cool the air circulating through your airways by removing the very barriers that keep you warm: your clothes. We’re not saying you start doing nudie runs as soon as the sun comes out, but people do tend to get excited at the first hint of sun and replace scarves with t-shirts and shorts.
The human body and its clothes aside, the two viruses that most commonly cause the cold are: rhinovirus and coronavirus. (Anyone else getting a visual of rhinos on a sandy beach in Mexico knocking back beers?) These two viruses flourish in cold but not too cold temperatures, aka: spring and autumn.
And then there’s hay fever.
Plants need pollen to get down and dirty – and we really need plants to be getting down and dirty too. But pollen is a fine powdery substance that easily becomes airborne – most commonly in spring and autumn – and is easily breathed in. If you have hay fever, you have an overreactive immune system, so when you breathe in pollen, your body treats it like a foreign invader and your immune system launches an attack. This causes nasal inflammation which makes it easier for viruses to set up shop in your nose. But also, the subsequent allergic reaction hogs all the attention: while your immune system is preoccupied with pulverising pollen, other baddies like rhinovirus or coronavirus find it easier to sneak in.
Recovery’s a pest, so prevention's best.
Hay fever sufferers should try to avoid breathing in pollen as much as possible. Easier said than done, we know, but there are heaps of suggestions here. Generally speaking though, when the air gets chilly, you can keep your airways warm by wrapping a scarf around the lower part of your face and neck – even at the start of spring. Washing your hands regularly – especially before eating or touching your face is probably the best way to stay virus-free. And while the evidence isn’t consistent, a recent review concluded that vitamin D may help, too.
The case for regular exercise, however, is solid. For the past 30 years, research around physical activity and the immune system has shown that exercise boosts your body’s built-in defences. No matter what you’re doing - running, walking, swimming, riding, or nudie runs - within minutes of starting your routine, the cells of your immune system begin circulating throughout your body. It’s been shown that people who exercise 30 to 45 minutes a day experience a 40% to 50% reduction in the number of days they get sick. So, the more active you are – the more active your immune system tends to be.
To rest or push-through?
Sometimes no matter what we do, we get sick. Even if we wrap ourselves in a scarf from head-to-toe and get in a cardio workout every day. What then? Do you crash on the couch? Or hit the gym anyway? Well most researchers agree that if your symptoms are taking place above your neck: you’re fine to exercise. But in moderation; you should be able to hold a conversation while doing it.
Opinions are divided, however on whether your moderate workout will make you feel better. Some say it will give your immune system a little boost, others say it won’t make a difference. But again, most agree that moderate exercise when you have the common cold won’t make you worse or prolong the illness.
If your symptoms are below the neck, the story is very different. If you have the flu, for example, which is most prevalent in winter months – and much more severe than the common cold – it’s time to rest. Scientists first figured this out back in 1940 when they realised athletes infected with Polio got worse after playing a game of football. Follow-up studies found that a body infected with flu can react very poorly to physical activity. The ‘sweating it out’ approach when it comes to neck-down illnesses simply doesn’t work. In fact, it makes you worse.
The take-home message.
It goes without saying that you should always listen to what your body is telling you. But if your symptoms are above the neck and you feel like exercising: go for it. Just bring it down a notch (the intensity of your exercise, not your neck because that would get messy). On the other hand, if your chest is sore, you’re feeling nauseous, or you’re experiencing any symptoms below the neck – rest is best.
At HeadUp Labs we’re collecting data on our users’ health every single day and using it to tell them a detailed story about their own body. You can look in the mirror and see what’s going on on the outside, but it’s much harder to understand what’s happening on the inside. This is why we’ve made it our mission to help you get to know yourself on a deeper level: inside and out. Follow our journey on Facebook and Instagram, or jump onto our Twitter feed for our take on the current #health and #tech space.
*Please note: header image via We Love Cycling, https://bit.ly/2rPel6j