I tried on Bryan Johnson's brain helmet — it's a futuristic Apple Watch for your noggin

Kernel's Flow headset was designed by a former Oakley employee. I can see the resemblance to a fancy ski helmet. Maggie Shannon for BI I'm sitting in a small, dark room with my head wedged inside a very heavy helmet. It's surprisingly comfortable, considering its 5.5-pound weight, with dozens of plastic circles that look like little bedazzled lightbulb sockets gently burrowing through my hair and onto my scalp. Here I am, ready to measure my brain fitness . I'm taking two exams at the brain-measuring startup Kernel in Los Angeles. There's no great way to prepare for these tests, making the experience both nerve-racking and oddly relaxing. Nothing to do now but sit back and let the brain helmet probe the inner workings of my mind. Before he was that guy doing all the wildest things for longevity, tech entrepreneur Bryan Johnson started this headgear company in 2016.