I was aware of my heart murmur since I was 10 years old. It prevented me from participating in high school sports and kept me out of the military draft in the Viet Nam years. I was always cautious about exerting myself, but by the time I was 30 I started to read where exercise was actually good for the heart, not detrimental and that taking it easy was counter productive in the long term.
I got into running in a big way at 30 and ran a few road races each year, at first casually, not at a very competitive level. As I got fitter and stronger my times improved and my confidence rose and I got more intense with my training. The race times were never much to write home about, 20 minutes or so for 5K, but I was happy with that level. And I ran at the level for many years with no ill effects.
It wasn't until I was 39 that the bad valve manifested itself. I had a minor stroke on my 39th birthday which put me in a funk for many months. Luckily my cardiologist was forward thinking and told me to go back to what I had been doing with no restrictions. But he noted, when it's time you'll know. That was somewhat perplexing at the time. How would I know when I knew? What signs, what eventuality, what shocker bigger than a stroke would I need to let me know? He simply said, when you can no longer do what you're doing.
I returned to intense training and racing. At age 40 and 41 I ran some personal best times at 10k and 15k. Then in 1990 at age 42 I was in pretty good shape and expecting to run one particular 15K at about 7 to 7:15 per mile. All my training times told me that's what to shoot for. At mile 5 I was on target with about 35 minutes and feeling fine but then came a hilly mile that I knew would slow me down. Would it be 7:30, maybe 8:00? No, it took me 9 minutes. The third 5K of the race was at least a full minute per mile slower than the first two thirds and I was working just as hard, maybe harder.
Then came the recovery. Instead of a week or two after a hard effort like that, it was a month and I still didn't feel quite right. He was right, it was time. The valve leakage had taken a major jump. These things don't get worse gradually, they tend to worsen in steps. You suddenly just tire out far more quickly doing the same things you normally do. With me I can point to the day, time of day and the spot on a city map. I had the valve replaced several months later.
Now, I'm not trying to scare you any more than you already are. I'm trying to let you know what to expect. You'll just get increasingly tired for no good reason. There will be little doubt when you need it replaced but until that time you can't go hide in a closet. You can continue to push yourself and enjoy yourself. When it's time, you'll know.
