A cardiac surgeon ignored his own heart attack symptoms. He says anyone can miss the red flags.

• A cardiac surgeon thought he had a healthy lifestyle. A heart attack forced him to make changes.
• He ate well and exercised often, but his busy schedule left him stressed and sleep-deprived.
• He also found he was pre-diabetic, and learned to manage his blood sugar with simple habits.

Dr. Jeremy London was miles from home, out in the dark Georgia woods on a hunting trek with his teenage son when he was hit with a crushing chest pain.

He hadn't been feeling well that day, suffering from what he told his wife — and himself — was heartburn. That morning, when the couple went to take their dogs for a walk, he started pouring sweat, despite the chill in the December air. The symptoms came and went, easing when he sat down, and starting up again when he got moving.

These were textbook signs of a heart blockage, something London knew well from his daily work as a cardiac surgeon.

"I went, 'Oh shit.' I knew what it was. Symptoms brought on with exertion, relieved with rest is coronary angina until proven otherwise. That's what I do every day," London told Business Insider.

He couldn't quite believe it was happening to him.

London was, on the surface, doing everything right: eating well (his wife is a holistic nutritionist) and exercising often while training for triathlons and practicing jiu-jitsu.

But out in the field with his son that night, as the woods darkened to pitch black and London fell to his knees with the pain, he couldn't brush it off as heartburn. It was clear he was having a heart attack.

When he made it to the ER, doctors found a 99% blockage of blood flow in his right artery.

That was in 2022. Now 59 years old, London said his personal experience highlights how easy it is to put off your health or ignore red flags, even as an expert — and how a few simple changes can make all the difference.

"The bottom line is, many, many times we know better and we don't do better. It is a universal human trap, and none of us are immune," he said. "I mean, who would know better than me?"

Changes for a healthier heart

As London recovered from his heart attack, he was forced to be brutally honest about his health. He was great at exercising, but skimped on other healthy habits in pursuit of his busy career and active lifestyle.

"The most important thing for you is the thing you're bad at," London said. "For me, that's sleep."

After decades of working long hours and staying on call as a doctor, his ability to rest and relax was a mess.

Step one was working on his sleep hygiene, managing his stress, and improving his overall recovery.

But as London took a closer look at his health, he realized other habits weren't as healthy as he thought. For instance, he was shocked to find that he was pre-diabetic after trying a continuous glucose monitor on a whim.

To manage blood sugar, he started taking a short walk after eating, taking more movement breaks during the day, and including fiber and protein at each meal.

Hydrating for a healthier heart

He also hydrates consistently, drinking water first thing in the morning and keeping a bottle with him so he can sip throughout the day.

Dehydration can exacerbate stress on the heart and worsen mental and physical performance. London is an official partner of the water filter brand Rorra and uses their countertop filter daily to reduce exposure to environmental contaminants like PFAS, which have been linked to health issues.

"With my busy schedule and operations that can last hours at a time, it's easy for my hydration to take a back seat," he said. "Though it's far from perfect, I try to hydrate proactively."

Realizing how he had fallen short in caring for his health — and all the warning signs of heart problems he missed — was a humbling experience, but also an opportunity, according to London.

"The key is that you recognize it, you learn from that, and you're a better person at taking care of yourself and consequently everyone around you as a result of making those mistakes," he said.

How to know if your heart is healthy

London said most people don't realize that heart disease, not cancer, is the leading cause of death for American adults.

While factors like age, genetics, and environment play a role in heart health, the best way to protect yourself is to understand metrics that matter, such as:

• Blood pressure: hypertension or high blood pressure is known as "the silent killer" because symptoms can be hard to spot.
• Blood sugar: a key measure of metabolic health, balanced blood sugar is a sign that your body can handle energy efficiently.
• Cholesterol: we need some cholesterol for health, but too much LDL or "bad" cholesterol can build up and create a risk of blockages.
• Weight: maintaining a healthy weight helps to prevent excess strain on the heart and circulatory system.

Once you've checked your baseline heart health and understand how it compares to normal ranges for your age group, it's easier to get the most bang for your buck in forming healthier habits.

"There are some really simple, although not easy ways to move the needle, to protect yourself from cardiac events or to then reset yourself if those things have already happened," London said.