Four months after the release of his first book, Dr. Athan Smyrlis is already seeing what he hoped for: meaningful changes in the lives of the people closest to him — and in the patients he treats every day.
The Rockville Centre resident’s book, “Why So Tired?” published True Health Compass LLC in January, offers a 101-day guide to improving energy, sleep and mental clarity through small, consistent lifestyle changes. Since its release, Smyrlis said, the response has been overwhelmingly positive, both from readers and from those he treats in his practice.
“I wrote it for my family, my friends and my patients,” he said. “To now see it actually helping people feel better, that’s the most rewarding part.”
Smyrlis, 45, has been a clinical and interventional cardiologist at Mount Sinai South Nassau hospital, in Oceanside, for the past decade. Born and raised in Greece, he specializes in invasive cardiology and regularly treats patients with serious heart conditions.
But it wasn’t just his professional experience that inspired the book — it was also personal. For years, Smyrlis said, fatigue was one of the most common complaints he heard from patients, often without a clear medical explanation. Then, he experienced it himself.
“There was a period in my life where I felt completely drained,” he said. “I did all the testing. Everything came back normal. But I knew something wasn’t right.”
That experience changed his perspective. Smyrlis began studying patterns in his own life — sleep habits, stress, diet and work schedule — and discovered the impact of disrupted routines, particularly on the body’s circadian rhythm.
“Being healthy is not just not being sick,” he said. “It’s feeling good, having energy, being present in your life.”
Motivated by those insights, Smyrlis spent several years researching fatigue, sleep science and lifestyle medicine, while also testing practical changes in his own daily routine. He began sharing those strategies with patients, often in brief, simplified steps during office visits.
The results, he said, were striking.
“People would come back months after, looking and feeling like a different person,” he said. “But in a 15- or 20-minute visit, there’s only so much you can explain. That’s when I realized I needed to put it on paper.”
The result was “Why So Tired?” which is structured to meet readers where they are — especially those too exhausted to tackle traditional, dense health guides. The 101-day format breaks down lifestyle changes into small, manageable steps designed to have a cumulative effect.
“The people who need this the most often don’t have the energy to read a long book,” Smyrlis explained. “So I made it simple, almost like a daily guide. I also made sure not to make it too scientific and much more relatable. ”
At the core of the book is a straightforward philosophy: consistency matters more than intensity. Rather than drastic overhauls, Smyrlis emphasizes small, repeatable habits like improving sleep routine, getting morning sunlight, eating balanced meals and incorporating light daily movement.
“Small habits, done consistently, start to compound,” he said. “They build on each other. And over time, they create real change.”
Among the most important recommendations are three simple steps: going to bed a little earlier while limiting screen time at night, getting natural light within the first hour of waking, and starting the day with water and a protein-rich breakfast.
“They sound almost too simple,” Smyrlis said. “But when people actually do them consistently, the results are real.”
Since its release, the book has received strong feedback beyond his immediate circle. Early reviews from readers and online platforms praised its accessibility and practicality — something Smyrlis said was especially meaningful.
“When feedback comes from people who don’t know you, who have read thousands of books, that really matters,” he said.
In his practice, Smyrlis has also seen a shift in how he approaches patient care. While he continues to treat serious cardiovascular conditions with traditional medicine, he now spends more time addressing underlying lifestyle patterns that may contribute to long-term health issues.
“Often, when you go back into someone’s life, you see the same patterns,” he explained. “When those improve, everything else becomes easier to manage.”
In some cases, he noted, patients who adopt healthier habits are able to reduce their reliance on medications over time, under medical supervision.
“Lifestyle is powerful,” Smyrlis said. “It doesn’t replace medical care, but it works alongside it.”
He is working on an audiobook version of “Why So Tired?” expected before the end of the year, and is considering future projects that would expand on the book’s principles, including a potential wellness retreat focused on lifestyle changes.
For now, Smyrlis remains focused on his patients and on continuing to spread a message he believes is increasingly important. “Fatigue is often the first sign that something is off,” he said. “It’s an early warning, and an opportunity to make changes before more serious problems develop.”
Smyrlis, who lives in the village with his wife and two daughters, said his goal is simple: to help people feel like themselves again.
“I see how hard people are trying,” he said. “This is about giving them a path forward, one step at a time.”
