The ankle/brachial index (ABI) is an objective measurement of lower-extremity arterial blood flow and distribution of oxygen and nutrients to the body tissues. Treadmill exercise testing with post-exercise measurement of ankle/brachial indices may be used in addition to resting measurements of lower-extremity arterial pressures and pulse volume recordings. In patients with lower-limb pain, treadmill testing can confirm or exclude peripheral arterial disease (PAD) as the likely cause. The ankle pressure and ABI drops after exercise in patients with intermittent claudication (pain in legs with activity) due to PAD. In addition to evaluating the effect of exercise on the ankle-level blood pressure, treadmill exercise testing also offers a means to characterize the functional impact of claudication symptoms.