Can a woman answer this, too? I lift weights so, I have a stronger upper body and arms. But, I ride a bike and use a treadmill, too.
I think... how it might all be related is the way, the blood is able to flow through your arms and legs due to oxygen.
Blood flow is certainly the issue, and I was surprised to learn "a heart attack" is not caused by something being wrong with one's heart. Rather, it is "an attack on the heart" ... and the problem stems from the circulatory "plumbing" around or even near the heart, and some of us seem to have poor plumbing in that area. In my own case, just holding my arms above my shoulders for several seconds is somehow enough to reduce or restrict the flow of blood to my heart and cause a shortness of breath and angina (chest pain). I really know very little here, but I do know keeping our plumbing cleared out -- read: radical diet change -- can be a life-or-death matter.