Your keys aren't in the spot you thought you left them? Can't recall the title of a book? I've had those moments.

Amid our busy lives, distraction or fatigue may explain our forgetfulness. But instances of 'brain freeze' make me realize I want to do everything in my power to help keep my brain sharp.

There's plenty of evidence that exercise can help protect our bodies and brains. And as we age, daily movement doesn't need to be super intense. In fact, a new study finds tai chi, a form of slow-moving martial arts, can help slow down cognitive decline and protect against dementia.