Does anyone know if Zazen puts stress on the heart that can cause problems, especially to those with a heart disease. Here is a bit background and why I ask that question.

I'm in my early thirties and had a heart angioplasty (stent placed in blocked artery) done last year. I have a family history of heart disease and high cholesterol. After the stent was placed occasionally I used to get slight pain (kind of sore feeling in the heart) especially after intercourse. It used to go off by itself in a day or two.

After I started Zazen few months back, I started noticing that the sore feeling in the heart was happening more often. I first didn't think it was due to zazen but after many instances I found that zazen was causing it. Yesterday I went to a whole day of zazenkai and found that the pain was more apparent. I think that zazen might be putting some sort of stress on the heart.

I'm thinking about cutting down on my sitting from 30 min to 20 min. I hate to do that but doesn't seem like I have an option.

I would like to seek your views on this. Do you know of cases where Zazen can put stress on the heart?

- Sam