A cardiologist says these 3 signs could indicate heart problems for people in their 20s and 30s

• Heart attacks are increasingly common in adults under 40.
• It's important to know the signs of heart conditions at any age, even in young adulthood.

Many people under 40 don't consider themselves at risk for heart problems, a recent survey by Ohio State University suggests. But heart-attack statistics from the past two decades tell a different story.

A landmark study published in 2019 found that the overall rate of heart attacks in the US had declined since 2000, but cardiac events had become more common in the under-40 age group. What's more, it found that the youngest heart-attack survivors were just as likely to die of a future heart attack as the middle-aged survivor group.

Marc Katz, a preventive cardiologist, told Insider that most heart conditions that affect young people have nonspecific symptoms, such as dizziness or shortness of breath. Getting checked by a physician is the only surefire way to rule out a cardiac cause.

"Sometimes a simple physical exam, like listening to someone's heart, can help us evaluate if there's something abnormal about the heart muscle that requires further investigation," Katz said.

Katz, who's 33, said some of his friends will text him for nonurgent medical advice. But not everyone has a doctor in their back pocket, and even medical professionals have missed the signs of their own heart attacks before.

Here are three key signs that you should get checked for heart disease at any age, even your 20s and 30s.

Shortness of breath during exercise

Katz said he'd seen many patients complain of shortness of breath after exercising for the first time in a while.

"Because they're trying to get back into fitness, they can't answer the simple question of 'Am I just out of shape, or is this something more serious?'" he said.

Answering that question can be as simple as doing a stress test to measure how the heart functions during physical activity, Katz said.

According to the Mayo Clinic, a stress test can reveal whether the underlying problem is blocked blood flow — which would point to heart disease, especially in older people — or an irregular heartbeat, called arrhythmia.

"For younger patients, again, it requires that conversation with a physician one-on-one to really elucidate if it sounds more serious or not," Katz said.

Fainting or dizziness

While fainting is not always related to the heart, it may be a sign of reduced blood flow to and from the vital organ.

"If you ever pass out, especially if you're exercising and you pass out, those are some symptoms that you should 100% be seeing a doctor for," Katz said.

He added that other symptoms such as palpitations, lightheadedness, and dizziness should also set off alarm bells for young and otherwise healthy folks.

Racing or irregular heartbeats

If you feel like your heart is beating too fast or too slow, or like it's skipping a beat, you should see a cardiologist to rule out the possibility of a functional issue.

Heart palpitations may also be associated with anxiety or stress, but Katz said anxiety is a "diagnosis of exclusion" for cardiologists. Without an exam to evaluate the heart's rhythm and muscle function, there's no telling that anxiety alone is causing the heart to race.

"Often patients with anxiety can have palpitations that can make them more anxious, and that anxiety can give them more palpitations," Katz said.

Sometimes seeing a cardiologist can ease a patient's anxiety even if there's nothing wrong with the heart. A simple reading like an EKG can give both patients and providers more information, giving everyone some peace of mind.