Sustained and acute increases in blood pressure can dampen pain in experimental animals and humans. The most important clinical implication of this relationship may be the phenomenon of silent cardiac ischemia. High blood pressure is common in people at risk for cardiac ischemia and may reduce angina, the key symptom of life-threatening ischemia. The relationship between resting blood pressure and angina was examined in 904 people undergoing exercise stress testing for coronary artery disease. The presence or absence of ischemia was documented with single photon emission computed tomography (SPECT). Participants with ischemia had higher scores on the McGill Pain Questionnaire (MPQ) following exercise though this was moderated significantly by diastolic blood pressure (DBP), especially in women. People with higher pre-exercise resting DBP who displayed SPECT-diagnosed ischemia had MPQ scores comparable to people who did not display ischemia, independent of age, exercise duration, medication, and cardiac history. Awareness of the potential association between blood pressure and angina may provide patients with coronary artery disease and their physicians' important guidance.