Collapsing during strenuous activity is typically heart failure in my experience.

It happens all the time up here in Canada when people shovel snow.

Almost. I think you're confusing "heart failure" with "myocardial infarction." They are two different diseases. Collapse during exertion can happen in either one, but in Seth's case myocardial infarction is more likely, because people with heart failure generally don't go hiking (their exercise tolerance is too limited).

I may very well have confused the two as I am not an expert in the topic. Thank you for the clarification.

From his last column, linked to above:

"It was nice to know all that but I did wonder: Was I killing myself? Fortunately I could find out. A few months before my butter discovery, I had gotten a “heart scan” – a tomographic x-ray of my circulatory system. These scans are summarized by an Agatston score, a measure of calcification. Your Agatston score is the best predictor of whether you will have a heart attack in the next few years. After a year of eating a half stick of butter every day, I got a second heart scan. Remarkably, my Agatston score had improved (= less calcification), which is rare. Apparently my risk of a heart attack had gone down."

No. Coronary calcification is but one stage in the process of atherosclerosis. So he could have had severe atherosclerosis without extensive calcification. This is why coronary CT is not a perfect test for prediction heart attacks. Furthermore, coronary CT cannot assess the tendency of the blood to clot, which is a function of both local and systemic factors. A useful guideline is that physiology is never as simple as one test or one variable.

In case you're still checking this thread, I just wanted to let you know how much I appreciated your efforts to educate and correct the record. I know a little about this area, and know enough to see you know more than I do. It's a sad, recent phenomenon of software engineers projecting the epistemic structure they deal with day-to-day onto the medical world.

(quick edit) It's profoundly sad to watch http://quantifiedself.com/2010/09/seth-roberts-on-arithmetic... all the way through as a result of this story. It's complicated... maybe it's a failure of medicine, of medical care delivery, education, etc but a room full of educated people laughing off the comments by that person warning of artherosclerosis/stroke and Robert's responses... it's just not a good sign.

This is what I love about HN. The knowledgeable community. Thank you.