The purpose of this study is to evaluate the change in Walking capacity after an intake of caffeine. The study design is cross-over and follow-up of 80 patients with leg pain caused by narrowing of their leg arteries, Peripheral Vascular Disease (PAD), stage II. Half of all will be revascularised, follow up will be after 3 months. It is hypothesized that caffeine (6mg/kg) can be a cheap, safe drug before walking exercise. Primary endpoint is maximum walking distance (MWD), treadmill-testing,(constant load, 0%,2m/h). Secondary endpoints are pain free walking distance (PWD), maximum muscle strength, endurance, reaction speed, balance, cognitive function, health related quality of life (SF-36).