Michael Mosley runs an experiment to discover whether gentle yoga can lower your blood pressure as much as vigorous exercise. Alain Gregoire tests the latest meal replacement shakes to see if they are as healthy as they claim. Zoe Williams discovers why wearing your contact lenses in the shower can put your sight at risk. Giles Yeo tests whether fancy gourmet salts are any healthier than table salt. And Guddi Singh discovers a surprising way to ease the symptoms of Parkinson’s - ballet.