From October 5th through October 11th, I actively rejected sleep (2 - 4 hours of sleep) and took in quantities of caffeine ranging from 1.5 g to 2 g. (A cup of coffee has approx 100 mg and a strong energy drink has about 250 mg). I was preparing for launch of my product and subsequent YC application. On Saturday morning, October 11th, I had massive chest pains and I collapsed. Fortunately, everything is alright with my heart. Overall though, I felt incredibly stupid about my actions.
As hackers and entrepreneurs, it's really easy to fall into the trap of your launch being the most important thing in the world. It's not. You need to be healthy, as business is a marathon and you'll be running for awhile.