FitbitThe news this week that Fitbit attracted $42 million investment capital follows Withings’ announcement of $30 million (including Euro11 million from BPIFrance, the French national investment fund), Jawbone’s recent acquisition of Bodymedia for $100 million in April 2013, and MyFitnessPal raising $13 million earlier this month.

The quick arithmetic for these four companies alone adds to roughly $200 mm in a few months going to these brands, which are feverishly competing for the heartbeats and footsteps of people who are keen to track their steps and stay healthy.

Can you keep up? You need a new kind of activity tracker to track the movement of money into mobile health. Following the #mhealth hashtag on Twitter helps (but be forewarned: it can be blindingly fast-moving if  you watch your Tweetdeck column in real-time).

Health Populi’s Hot Points:  My observations of the growth of digital health companies at the 2013 Consumer Electronics Show were summed up as the “Battle for the (wrist)Bands,” published here on Health Populi in January 2013. It’s eight months later, and the battle is now a pot-boiler. My skills in market forecasting are being challenged: on one hand, this is exciting for a health economist who believes in patient engagement and self-care – my trademarked HealthcareDIY movement.

On the other hand, my business brain-nodes are buggered by bubbles-on-the-brain.

I learned about technology adoption at the foot of Ev Rogers when he was a visiting professor at the University of Michigan. His S-curve of technology adoption has been burned into my brain for over twenty years.

So the rational part of me knows that a bubble is a very real possibility.

The $200 million (or more) question is: will consumers elect to spend $50 to $100 on each of these devices? How many? How quickly?

We’ll be tracking this market niche ongoing. I can argue both sides of this equation. I admit: I’m hedging my bets. I personally own four of these devices, paid-for out of my own pocket. A new Misfit Shine arrived ten days ago that I’ve yet to unwrap and try out.

Would that I was an octopus with more time on my hands…er….wrists.