The SF Business Times reports the news via figures from Slice Intelligence, which tracked email receipts for the month of May. These only track online sales, of course, but they used the data to assert that the launch of the Apple Watch did not put a dent in Fitbit's sales, despite the watch's touted abilities to do the same health-related tracking. In May, 850,000 Fitbit devices were sold versus 777,000 Apple Watches.
Apple Insider scoffs at the doomsaying around the watch, saying JP Morgan expects Apple to ship 26 million watches by year-end. Bloomberg says that the consumer bases for Fitbit and Apple Watch "don't overlap much" because of the difference in price point.
These sales figures may or may not be such important metrics given the newness of the Apple Watch, but I'll just add a little anecdotal evidence here via a friend who purchased one of the first Apple Watches and has been using the health monitoring functions.
He said, following a day in which he ran several miles on a treadmill in the morning, walked to work in New York City, returned to the gym and did squats and weight training at the gym, he returned home to sit down to eat and check some email when, ten minutes in, his Apple Watch dinged him and said it was "Time to stand up."
"I just did five sets of squats!" he screamed. "I stood up more than anyone in the world today!!"
Anyhow, it looks like the watch may still have some kinks to work out, like all first-generation Apple devices have.