What type of pain do patients with ischemic rest pain typically experience?

Patients with ischemic rest pain typically experience pain, particularly in the lower extremities, while they are at rest, especially in a horizontal position. This occurs because the blood flow to the limbs is severely restricted due to advanced peripheral artery occlusion. When a patient lies down, blood flow may not be sufficient to meet the metabolic demands of the tissue, leading to pain. This pain often intensifies when the affected limb is elevated or in a horizontal posture, and it tends to improve when the patient hangs the leg over the side of the bed or stands up, allowing gravity to help in perfusion.

Other types of pain mentioned in the options refer to different vascular conditions or mechanisms of pain that do not specifically relate to the resting ischemic environments that characterize ischemic rest pain. Intermittent pain during exercise typically refers to claudication, where pain arises during physical activity due to temporary ischemia. Chest pain might relate to cardiac issues rather than limb perfusion problems, and cramping pain in the lower back does not correlate with the typical symptoms of ischemic rest pain, which focus on the limbs.