Yes, I don't know the exact number but low test could certainly cause heart issues (although I would imagine it's somewhat less likely for those who diet and exercise properly). But you can have extremely high cholesterol and be on the brink of a heart attack or stroke and have zero symptoms... it's actually pretty common.I think below 400 and youre at risk for heart issues.
Like I said, I agree with @Mathb33 that that a well controlled healthy test is always better than a low one. My point was that a lot of people look at their test and immediately point to it being the culprit of not feeling great because it's lower than they thought... and sometimes that is the case... but there are certainly plenty of times where it is not. Someone might think that their test needs to be at 1000 because they felt great when it was and they felt much worse when it was 600... but that's not necessarily the solution. There can be plenty of other variables why someone "felt better" at 1000 than 600 and it may not be entirely or at all related to the higher test. That's all I'm trying to get at.