5 Red Flag Signs You're Getting Sick

These subtle signs might not seem like anything, but they could be early clues your body is fighting off an infection.
There are some not-so-obvious warning signs your body is fighting off a virus, according to experts.
staticnak1983 via Getty Images
There are some not-so-obvious warning signs your body is fighting off a virus, according to experts.

Recently, respiratory viruses – such as influenza, rhinoviruses and respiratory syncytial virus, better known as RSV – have made a dramatic comeback.

In 2022, for example, influenza activity swiftly returned to pre-Covid pandemic levels and the United States saw a particularly severe RSV surge.

Many respiratory pathogens spread faster and further than they had in the previous two years.

Though the 2023-2024 cold and flu season is just getting started, experts fear it’ll be on par with last year.

In other words, stuffy noses, sore throats, coughs and fevers are coming for us.

As we head into respiratory disease season, it’s worth keeping a close eye on your health. Before the more obvious cold and flu symptoms appear, there are usually a few signs that indicate an infection is brewing.

If you catch them early enough, you just might be able to intervene and give your body the care it needs to improve your recovery.

At the first sign of sickness, “you should focus on staying hydrated, eating well, getting plenty of sleep, maybe staying in if possible, and relaxing a bit more to ensure you save your energy to fight the illness,” said Aimee Bernard, assistant professor in the Department of Immunology and Microbiology at the University of Colorado Anschutz Medical Campus.

Here are some of the very first clues you’re getting sick:

You have a tickle in your throat

Before you develop a full-blown sore throat, there’s often a tickle or lump that forms in the back of the throat. In fact, this is often one of the first noticeable signs that an illness is about to strike.

When you’re exposed to a pathogen — say, a rhinovirus or adenovirus — the body reacts by producing molecules that fight off an infection, explained Dr. Natalie Cameron, an instructor of general internal medicine and epidemiology at Northwestern University Feinberg School of Medicine.

One such molecule is bradykinin, which, during a respiratory infection, travels from the nasal passages to the nasopharynx. There, it stimulates sensory receptors in the throat, which is thought to contribute to that swollen, raw feeling in your throat, Cameron said.

You’re feeling fatigued

Before the classic respiratory symptoms kick in, you’ll likely feel run down for a day or two. “You might feel unusually weak and lacking in energy,” said Dr. David Cutler, a board-certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, California.

This is because the body releases cytokines, key communicators between cells in your body, at the start of an infection. These cytokines activate immune cells to start fighting the infection. This process triggers inflammation throughout your body, which can leave you feeling wiped out, Cameron explained.

The same goes for muscle aches. All that inflammation building at the start of an infection can cause your muscles to feel weak, achy and tired, Cutler said.

You can’t stop sneezing

You may notice that in the days before you develop congestion or a cough, you feel extra sneezy. Bernard said this is the body’s way of forcefully eliminating a virus. It’s the same process that happens when you inhale pollen or pepper.

“It is a great defence to get rid of anything that is irritating or damaging your airways,” Bernard said.

This is exactly why it’s so crucial to cover your mouth when you sneeze. Sneezes are so effective at expelling viruses, that “if you let the sneeze fly free, you are giving the virus a free ‘airline’ ticket to land far away on another possible victim,” Bernard said.

You suddenly have a headache

A headache is another clue an infection is cooking. In some cases, a headache results from the pressure building in your head as your sinuses begin to get clogged up with mucus. Having trouble sleeping or being dehydrated — which can occur in the early days of an illness — can also cause your head to throb, Bernard said.

Headaches may also be triggered by all the inflammation your immune system is producing as it revs up to fight the infection. While inflammation — the recruitment of immune cells to the site of infection — is a good thing, it may sometimes cause the pain of a headache, Bernard noted.

You become irritable or weepy

People often report feeling cranky and irritable when they’re getting sick.

“Some people experience emotional lability – more weepy – others just want to be left alone,” said Dr. Theresa Fiorito, an infectious disease specialist and director of the Family Travel Medicine Center at NYU Langone Hospital—Long Island.

This is so common, in fact, that doctors have labelled the mood swings and behavioural changes that occur during illnesses as “sickness behaviour.” Research shows that people’s moods tend to dip when they have the common cold or influenza — even during the asymptomatic phase.

It’s believed that the symptoms associated with sickness behaviour, like anhedonia and reduced social interactions, motivate people to lay low at home, ultimately giving their body the opportunity to rest and recover. Plus, if those other early warning signs are affecting your well-being, it’s understandable that you might feel crummier than you usually do.

“If you haven’t slept, or your appetite is poor, and overall because you don’t feel well, it will naturally affect your mood,” Fiorito said.

All of these early symptoms are a sign that it’s time to start taking care of yourself to help your body fight off the impending illness. Stay hydrated by aiming to drink six to eight glasses of water a day. Avoid sugary beverages like soda, power drinks or fruit juices, Cameron advised, and try to get between seven to nine hours of sleep at night.

“Paying attention to all of these early warning signs can alert you to the need to take extra good care of yourself over the next several days to week,” Bernard added.

You may not be able to completely dodge the infection, but if you can ease the symptoms and quicken your recovery, why not listen to your body and give these tips a try?