People tend to get sick more often in the winter when the temperatures drop and it's harder to avoid those indoor germs. But why do some people seem to get sick every few weeks, even if they're eating healthy, exercising, and getting enough sleep? Here, experts break down what might be causing that reoccurring illness.
The most common reason you get sick all the time
If you find yourself falling ill almost every other week, your body is trying to tell you something: you're stressed.
"It's partly because we let ourselves get run down, stressed out and ultimately burnt out," Dr. Sarah Cook, the lead physician at Toronto's Integra Health Centre, told HuffPost Canada in an email. "We don't take care of ourselves, so we are sleep-deprived, we don't drink enough water, and we aren't eating a balanced diet. Our immune systems are down, and we become more susceptible to infections."
WATCH: Creative home remedies to cure your cold. Story continues below video.
Family physician Dr. Soreya Dhanji, of Toronto's Cadence Health Centre, added that stress can also have physical manifestations, which factor into why we get sick.
In addition to giving us anxiety, stress can make people feel nauseous, cause vomiting, and give heart palpitations, which can make them feel like they're sick, Dhanji told HuffPost Canada.
Other reasons you're constantly getting sick
It could be genetic: "It is possible to have a weaker immune system than other people," Dhanji confirmed, and studies have proven that genetics are a factor in this. However, exposure in childhood and adolescence could also contribute to the strength of our immune systems.
"There is a theory that the more viruses and bacteria that you are exposed to in childhood, the 'smarter' your immune system may become," Cook said. "So keeping things extra clean and covering our kids in hand sanitizer may be doing more harm than good."
Not enough sleep: There's a reason doctors always order you to rest when you're sick. "When we sleep, we produce cytokines, which are protective [proteins that] help us fight infection. So when we are under-slept, we can't produce as much, and we are more vulnerable to infection," Cook explained. How much sleep you need depends on your age, but adults need roughly seven to nine hours, according to the National Sleep Foundation.
You're dehydrated: When your body doesn't have enough fluids, it can't function properly. Water helps deliver nutrients and minerals to your cells, and helps keep your nose, mouth, and throat moist to prevent illness (the mucus and saliva acts as a protective barrier).
Too much caffeine or alcohol: Not only can caffeine or alcohol make us dehydrated — thus making us more susceptible to illness — but it can also disrupt our sleep and cause us to get sick. Specifically, since caffeine is a stimulant, it can not only make it harder to fall asleep, but a past study showed that having caffeine six hours before bed can cut sleep time by one hour. As for alcohol, it blocks REM sleep, which is the restorative type of sleep that makes us feel well-rested in the morning.
Poor oral hygiene: This surprising reason actually makes a lot of sense. "We have a lot of bacteria and bugs that live in our mouth," Dhanji said. "Oftentimes if we aren't taking care of our oral hygiene, we can either transmit that bacteria or cause other things, such as inflammation of gums, tooth infections, etc."
Inflammation in the mouth can also cause inflammation in other parts of the body, such as blood vessels, WebMD reports.
You have a chronic illness: People with chronic illness are more likely to get sick more often, simply because "it can decrease our ability to fight certain infections," Dhanji said.
Not washing your hands: This might be common sense, but if you keep getting sick, you might not be washing your hands enough. This is especially important in the winter, when being forced to stay indoors can lead to more germs in the air and on surfaces. "Also, touching our face often, we risk transmitting infections from our hands to our face," Dhanji added.
Lack of vitamin D: Studies show that vitamin D helps boost your immune system, and can help reduce the risk of respiratory infections, such as colds and the flu. Foods high in vitamin D include egg yolks, mushrooms, and salmon. Vitamin D supplements are also an option.
You have kids: Yep, your children could be the cause of your frequent illness. Since young children get sick more often, they could be bringing home "all sorts of viruses" from school or daycare. "And if mom [or] dad are rundown, they are more likely to get sick," Cook said.
You're getting older: Sorry to break this to you, but your immune system might not work as quickly as it once did when you were younger. As you age, you have fewer immune cells, which also take longer to react to germs and bacteria, WebMD reports. As a result, you get sick more often.
You interact with others often (directly or indirectly): This puts you at a higher risk of catching a virus, Dhanji said. "Something as simple as riding on transportation when someone sick has touched the door and you touch the door can often cause you to get sick," she elaborated. "Certain populations we interact with, specifically young children, can [also] be big factors in viral and bacterial illness transmission."
How to stop getting sick all the time
You likely already know the answer to this, but proper sleep, nutrition, exercise and staying hydrated will help prevent you from getting sick.
"I'd say sleep is a number one factor," Dhanji said, as this will help your body fight the infection and get your immune system back on track.
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Staying up to date on vaccines, making sure you wash your hands, and taking zinc and vitamin C to strengthen your immune system can also help prevent illness, she added.