Buddhists have been doing it for centuries, but in the age of distraction others are now learning the benefits of "training" their attention in the same way that we train our bodies. Here is an interesting reflection on the topic from BigThink.
...we need to learn to train our attention because, as with anything, attention is like a muscle. It's an analogy that you hear over and over in psychology - self-control is like a muscle - because it's an analogy that works incredibly well.
So if you train it, it gets stronger, it gets better. You are able to lift more weight, we have more endurance. And similarly with attention the more you train yourself to uni-task and to only pay attention to one thing at a time, the longer and longer and longer you’re able to maintain your focus.