Athos workout wear includes sensors that measure muscle activity. Tim Mantoani/Courtesy of Athos hide caption itoggle caption Tim Mantoani/Courtesy of Athos Shots - Health News Will Smart Clothing Amp Up Your Workout? KQED April 3, 2015 Startups are developing clothing with sensors that measure heart rate, breathing and muscle activity. Fitness enthusiasts are the target market. But the garments could be used for health care, too.