This is the first part of a special series, "The Essentials: Inside the Curve," first-person diaries from the people on the front lines of the COVID-19 pandemic -- the essential workers risking their own health and safety to ensure others are taken care of. From doctors, nurses and paramedics to police officers, transportation and sanitation workers, you'll hear directly from those keeping the world moving while so many are quarantining at home and working to flatten the curve.

Today, a 39-year-old cardiologist grabs 15 minutes of sleep whenever he can grab it. He's separated from his family, including his six-month old son, only able to connect via FaceTime calls between shifts at his New York City hospital. He's not willing to put his loved ones at risk from the exposure he faces every day as he treats COVID-19 patients. But Dr. Hadi Halazun returns to the frontlines nearly every day, determined to see the crisis through. Through audio journals provided to ABC News, Dr. Halazun movingly remembers his first patient who died from coronavirus, expresses concern for his colleagues and talks about the toll of not seeing his family. Hear in his own words how he also finds inspiration and hope pouring from a community that supports the essential workers.

"The Essentials: Inside the Curve" is a special series from ABC Audio. Listen for free on Apple Podcasts (https://apple.co/2ROvcnw), Spotify (https://bit.ly/3ct575v), or your favorite podcast app.