Workout gear that recharges electronics

Charging a smartphone is obvious - especially since it can be the hub of workout tracking - apps to track distance or calories, music, taking selfies, or even instructional videos. There are other devices that could probably use a charge too - Bluetooth headphones, smart watches, heart-rate monitors or other sensors can all form an arsenal of fitness tracking and assistance. Night lights form part of a runner's safety gear too.

Workout gear needs to be moisture-wicking and comfortable and offer a full range of motion for the activities being done while wearing them. For this application, there might need to be some embedded USB cables that devices can plug into.

Pockets to store the device(s), maybe even with inductive wireless charging.

According to this video, this technology is plausible with nano-fibres. I thought something piezo-electric might do the trick, obviously, these engineers have a better handle on the how-to of it all. Still, the energy of movement is converted to electricity.

Ever get hot while working out? I figured some thermocouples might be able to generate some electricity.

I've seen hats with solar panels on them (to power fans if I recall). Some solar panels on the shoulders might work too.

All these might not be enough to make a normal USB current; all I'm really looking for is a way for batteries to last longer.

If all these features add heat to the user's body, it's not going to be an effective product. Ideally, it would actively cool the user. The law of conservation of energy says the heat generated to another form should mean a better heat transfer away from the body, though in practice I doubt this will hold true. Most cooling solutions actually use a fair bit of energy to accomplish anything.