Can yoga breathing exercises be of any use when oxygen levels are low? This was the question that director Mike Raymond posed when he followed seven well-trained practitioners of yoga on their way to ever greater physical and spiritual heights. From the sidelines, bemused alpacas look on as the group gives a sun salutation at six thousand metres against the backdrop of a Peruvian mountainscape. There’s more than a chance of this being the highest yoga session in the world. Serious practitioners of yoga treat their breathing exercises thoughtfully and carefully. So, all things being equal, it should work, but this is not scientifically substantiated in Zen Summits.