First heart attack in 1995, double bypass in 2003, stent in 2004. I have applied for disability due to agent orange exposure in Vietnam. My understanding is that they rate the disability based on several factors, one of which is METS. My cardiologist has rated me at 1-3 METS. When I read about METS it appears it is a measurement of activity. If it is used in evaluating one for disability it sounds like it is a measure of your heart's ability. Can members give me a better understanding of the term and its use?