Which of the following factors is a major contributor to stable angina pectoris due to coronary ischemia?

Stable angina pectoris is primarily caused by ischemia resulting from coronary artery disease, which often involves the narrowing of coronary arteries due to atherosclerosis. Aging is a significant factor in the development of atherosclerosis because as individuals grow older, there is an increased likelihood of the accumulation of plaques within the arterial walls. This process diminishes the elasticity of blood vessels and leads to chronic narrowing that can restrict blood flow during times of increased myocardial oxygen demand, such as during physical exertion or stress, which presents as stable angina.

While factors like high cholesterol levels are also relevant in the development of coronary artery disease, they are not directly cited as a major contributor in the context of this question. Instead, aging inherently encompasses a variety of other risk factors including higher levels of inflammation, arterial stiffness, and other systemic changes that contribute to ischemia.

Low cholesterol levels and elevated serum calcium levels do not correlate strongly with the incidence of stable angina. Low cholesterol is typically not a risk factor for coronary artery disease, while elevated serum calcium levels are more associated with conditions such as hyperparathyroidism and do not primarily cause ischemic heart disease.

High physical activity can be a double-edged sword; it can increase the demand for oxygen and