The stench of progress: Sweat may power your personal tech in the not-so-distant future

Gross? Maybe, but at least your Fitbit is still working

Imagine you are out for a run with tunes fuelling your stride. Suddenly, your earbuds run out of juice and your good vibes come to a screeching halt. "Ugh," you groan as you look to your activity tracker for encouragement, only to realise it's dead too....