Maximum safe distance and intensity depends upon your conditioning and age. For example I am 52 and I'm in pretty good shape. I exercise 5 times a week for about 45 to 60 minutes. That includes running, yoga, plymetrics, weight lifting. I do these on different days, and they are intense workouts. During my more intense workouts I make sure my heart rate stays within a comfortable zone. For me it is around 130 to 145. If I get above 145 I'm going to hard, so I cut back and rest. My gage is this, "Can I talk while I'm running?" If I can't then it's time to kick back a bit.
Talk to your doctor and a trainer to find out what might work for you.
What would be the maximum safe distance to run/train for?
That was just a "Cliff Claven" (the windbag on the TV show Cheers)-type observation, not a personal judgment on the running of marathons LOL
Just a comment from watching The History Channel. It is said that the original Marathon runner, bringing the news of the ancient battle of 490 BC, dropped dead after arriving and delviering his message.
My opinion is that it is just too far to run. I don't think there are any health benefits to running that long. I understand the desire to complete one but I am not really in a position here to recommend one. Your primary doctor should decide if you need more studies -- I can give general advice, but try not to be specific. In general, if there are not changes in symptoms, a repeat echocardiogram is not necessary, but that is for your doctor and you to decide.
Do you mean marathons are not good for your health?
I just want to be able to say I did one and not do it again.
These echos were done before I started running. Is there a reason to do another one since I have been running for 2 years?
If your doctor feels comfortable that you have a structurally normal heart and normal EKG, running should not be a problem. Short bursts of SVT are almost never a problem, especially if they only last a second or two.
It is pretty normal to be wiped out after two hour run, I can tell you that from experience.
If the super long stuff bothers, cut back to shorter distances. Why do it if it isn't fun or if it causes you anxiety. Marathons are exactly "good" for your health so there is no reason to push up the distance.
Talk to your doctor and make sure they are ok with you doing a the marathon and if there is any question, stick to 5ks. 5ks and 10ks are great races.
I hope this helps. Thanks for posting.