Hi Sarah. This should be looked into, especially since it has happened twice. It is not unusual for an otherwise healthy man his age to have undiagnosed coronary artery disease. When a small artery to the heart (similarly for the brain) closes off briefly or goes into spasm or is clogged suddenly by a small piece of plaque that has dislodged from the wall of the artery, the result can be a heart attack (or stroke) with vague symptoms of chest pain (not in all cases), shortness of breath, nausea, sweating and dizziness. The symptoms may be mild but may indicate a more serious underlying condition that could be much worse next time if left untreated. For this reason, I would suggest you have him evaluated right away. If you cannot get into see his GP right away, take him to an express care clinic or the ER.