Back in 2001 a friend was out on a hill ride with another and stopped for while to tend some equipment. He was 44 and matched me for height and weight. While he was stopped, he had a heart attack and expired before the other rider noticed his prolonged absence and went back for him. This was about 2 miles from a convenience store where he died. I am now 46 and a little more overweight than he was, and I don't ride alone anymore unless I have to.