Until the first sign of a sniffle, it’s easy to take your good health for granted. But as you reach for the zinc and vitamin C, you might find yourself wondering: Is falling prey to a cold just a bit of bad luck, or the sign of a deeper-rooted immune issue?

Feeling sick is a drag. But don’t let your concern about your overall well-being spiral. In all likelihood, your immune system is strong enough, even if that sore throat, coughing, and congestion are making you feel otherwise. 

That said, there are specific indicators, beyond whether or not you currently have a cold, which can help you really figure out where your immune system stands. Some are fairly self-evident, like how frequently you get sick, but others are less obvious, like what’s going on with your gut health and stress levels.

You just have to know what to look for.

1. You Rarely Get Colds, Flus, and Other Bugs

The simplest way to gauge whether or not you have a strong immune system is by taking stock of how frequently you catch a cold, get the flu, or come down with a stomach bug. 

According to the CDC, there’s no magic number, but adults tend to average two to three colds a year.

There are always exceptions, of course. If your toddler just started preschool and brings home a new bug every other week, even with a healthy immune system, you’re unlikely to escape unscathed. But in general, if you’re taking basic precautions like washing your hands throughout the day and avoiding people who are sick, infrequent colds and bugs are a sign that your immune system is functioning as it should.

2. You Recover Quickly from Infections

It’s not just about how frequently you get sick, but how speedily you bounce back.

In addition to their two to three colds per year metric, the CDC asserts that healthy adults should recover from a cold in about a week to ten days. That may seem long, but keep in mind that three to four days alone are what it takes for a healthy immune system to develop the antibodies needed to battle the rhinovirus, which causes most colds.

3. You Have a Healthy Gut

The human digestive tract does way more than convert food to fuel. In fact, 70% of the immune system is located in our gut. Your gut microbiota, which is comprised of trillions of microbes, is crucial in regulating your immune system by protecting you against pathogens.

So where do you fall in terms of gut health? The science is still out on how we should even determine the exact markers of a healthy microbiome. But you may gain some insight into yours via the frequency of your stool.

Studies show a positive correlation between consistent colonic transit times—basically, having regular bowel movements—and a richer, more diverse microbiome. On the other hand, chronic constipation or its opposite, diarrhea, may be symptomatic of a weakened immune system.

4. Your Wounds Heal Quickly

Your body’s immune response is responsible for healing cuts, burns, scrapes, and bruises. An optimally functioning immune system makes it possible to efficiently cycle through the four phases of wound healing, hemostasis (stopping bleeding/coagulation), inflammation (which helps kill bacteria and rid the wound of foreign debris), proliferation (the filling and covering off the wounded area), and remodeling (the maturation and strengthening of newly generated tissue). 

The process is complex, with your immune system controlling the cellular communication that makes these four stages possible. Wounds that just won’t heal, or which take an excessively long time to do so, may signal a weakened immune system. Otherwise, injuries that aren’t too egregious should heal in four to six weeks. If that’s the case for you, go ahead and take it as a sign your innate and adaptive immune systems are functioning smoothly.

5. Your Stress Levels Are Low

Are you sick less frequently because you keep stress to a minimum, or are you less stressed because you have a higher-functioning immune system? The jury’s out, but what we do know is that lower stress levels correlate overall with a higher-functioning immune system. 
Further, studies have found that among a group of volunteers with colds, those subjected to experimental mental stress showed worse signs of illness than the control group.

6. Your Energy Levels are High

In addition to making you feel generally awful, chronic fatigue compromises your immune system. One 2012 study determined that a prolonged lack of sleep invokes both chronic low-grade inflammation and immunodeficiency, resulting in poor health. 

But you likely don’t even need scientific studies to confirm that when you consistently get too little sleep, you’re grouchy, foggy, and get sick more easily.

Daily Habits to Strengthen Your Immune System

Given the extensive science behind all the ways diet and lifestyle choices can significantly impact your immune system, there are four key areas to focus on that should help improve and maintain your health.

Get at Least 7 Hours of Sleep Every Night

Getting regular sleep is among the first lines of defense against illness. One 2022 study cites seven hours as an optimal nightly duration. 

While you might personally feel your best with more than seven hours a night, what’s key is taking care to foster and protect your sleep so you get what you need. Keep your bedroom cool (65 to 70 degrees Fahrenheit is ideal) and dark, leave distracting electronics elsewhere, and establish a calming bedtime routine so that when your head finally hits the pillow, you’re mentally ready for a night of uninterrupted shut-eye. 

Eat a Balanced, Nutrient-Rich Diet

What we eat can have a significant negative impact on our gut flora. Studies show that in wealthy countries, dietary changes (specifically, eating a diet low in fiber but high in salt, saturated fats, and refined carbs) along with sedentary lifestyles and excessive antibiotic use are all connected to a less diverse, less resilient gut microbiome, which seems to be linked in turn to a rise in inflammation and autoimmune disorders.  

The cure? As you’d might expect, it’s a nutritious diet including fruits and vegetables, whole grains, proteins, and probiotics. And the research backs it up, as in this 2007 study connecting healthy eating patterns to better immune function and lower inflammation in the study’s participants. 

Exercise Daily

Given that a sedentary lifestyle is part and parcel with a poor diet in terms of a weakened immune system, getting those steps in or hitting the gym seems more important than ever. 

One 2020 paper asserts that regularly getting 45 minutes of moderately intensive physical activity is absolutely a boon. Figure out what gets your heart rate beating at 64% to 76% of its maximum rate for your age, and go for it, whether it’s walking, swimming, cycling, light jogging, a dance class, or…well, you get the idea. 

Find Your Stress Relief

A meta-analysis of more than 300 studies supports the theory that brief, fight-or-flight stress may actually benefit your immune system (thanks to changes that enhance wound repair and stave off infection) but chronic stress has a detrimental effect. 

Of course, it would be glib to advise you to quit your job to escape the daily drag of dealing with a horrible boss. But the good news is that there are numerous other ways you can keep your cortisol levels under control. 

One 2009 study broadly defined leisure activities as hobbies, sports, time in nature, and socializing, and found that the more time participants spent on these activities, the less stressed they were. Meanwhile, this 2021 study across 130 countries found that mindfulness, which can be trained via meditation, was connected with lower stress levels. 

Whether it’s gardening or kickball, find your favorite leisurely pastime and stick with it—your immune system will thank you.  

Your Immune System Works When You Do

Your body works 24/7 to fight off infections. But honing your immune system to be as strong as possible starts with small, daily habits. Whether it’s a ten-minute mindfulness meditation practice, swapping dessert for fresh fruit, or taking the stairs instead of the elevator, all of these seemingly minor practices can positively influence your immune system health and thus, your overall well-being.  

So sleep well, eat well, get moving, and enjoy your good health!