The National Underwater Accident Data Center reports one-fifth of diver deaths can be attributed directly to panic attacks; experts ask if that number is even higher because of underreporting. Panic attacks under water can cause rapid, shallow breathing; hypoxia; carbon dioxide buildup; and irrational behavior. The diver could expel the regulator or try to bolt to the surface. These responses can cause the diver to pass out; suffer a heart attack; or become disoriented. Synchro is a new diving regulator that could analyze a diver’s breathing patterns and detect panic attacks, signaling the diver in advance that danger is imminent.