Exercise training improves walking capacity and regional perfusion in patients with Intermittent Claudication (IC). Endothelial Progenitor Cells (EPCs) and Endothelial Microparticles (EMPs) could play an important role in this process, promoting the healing of the diseased endothelium.

The investigators are going to measure EPCs and EMPs in a group of patients with IC and in a control group of healthy individuals before a treadmill test and 2, 24, and 48 hours after the test. Subsequently, a group of IC patients will be randomly assigned to perform a 12-week home-based exercise training program.

The investigators expect a significant increase of EMPs and EPCs after acute and chronic physical activity. We expect also a correlation between the increase of EMPs and EPCs and the improvement in walking capacity. Aim of the study is to demonstrate that acutely performed aerobic exercise could be able to promote the mobilization of EMPs and EPCs in patients with IC and that endothelial progenitor cells mobilization could play a pivotal role in exercise induced improvement of walking performance and endothelial function in subjects with IC.

Inclusion Criteria:

• history of stable intermittent claudication (PAD, stage II Fontaine)
• resting ankle-brachial index (ABI) <0,9 and the presence of occlusion or significant stenosis at the color-Doppler duplex ultrasound scanning

Exclusion Criteria:

• lower-limb ischemic rest pain or gangrene (Fontaine stages III and IV)
• inability to obtain the ABI value or to perform a walking test
• exercise tolerance limited by factors other than claudication (i.e., arrhythmias, cardiac symptoms or exaggerated blood pressure rise, severe obesity)
• end-stage liver or renal failure
• acute or chronic inflammatory conditions
• history of recent (<6 months) acute coronary syndrome, cerebrovascular event or inducible myocardial ischemia
• treatment with drugs known to affect walking capacity, including calcium-channel blockers, β-blockers and angiotensin-converting enzyme inhibitors.