Believe it or not there are personal tech devices and things like calculators and clocks, which run off water. What if we built a jogging or walking light which ran off of the sweat your body makes when you workout? What if we built another device, which ran off body sweat or water. The water could be used for drinking and powering the light? Or a sweatband with a membrane could collect the sweat and use the water to power it up. Not so far fetched really for instance all these new gadgets running on water these days.

http://www.popgadget.net/2005/12/water_powered_d.php

You see there are tremendous applications for this. How about for Survival, Astronauts and military; ultra-marathon athletes, etc.? Why not create a belt on the waste to collect sweat, hold or mount the light and use the water to drink and return to the bio-system and power up that light? Is it possible to make a belt around the waste which was a tube filled with water?

The water your body needs to replenish itself from strenuous exercise and at the same time collect your sweat running down your body and powering up a devices such as a running light? A light, which runs off of in essence your own bodies energy? Such a device could revolutionize the jogging light market sector and be a life-saver for military troops, survival gear or exploration teams? Think on it.