AS I PREDICTED MANY YEARS AGO, these wearable medical devices are revolutionizing medicine: Apple Watch able to monitor frailty in cardiovascular disease patients.

As I wrote in 2005: “Since these devices are based on two things — electronics and biological knowledge — that are improving by leaps and bounds, we’re likely to see a lot more of them, and we’re likely to see them become cheap enough, and capable enough, and reliable enough that they’ll attain widespread use.” Well, here we are. The “body computer” is close to reality.