Answer:
The myocardical oxygen supply has fallen below demand.
Explanation:
Angina is the name given to chest pain caused by decreased blood flow in the heart, which is called ischemia. The biggest cause of angina is atherosclerosis, which happens when plaque builds up inside the coronary arteries and this accumulation of fat causes the arteries to narrow or even become clogged, and the blood can't flow. Thus, the heart does not receive the necessary nutrients, such as oxygen, because of decreased blood flow, which causes chest pain.
Moderate activity is moving around for a reasonable amount. for instance, walking a little bit and taking a bike ride. vigorous activity is moving and exercising a lot, for instance going to the gym for four hours and lifting weights while on the treadmill. BTW don't do that XD.