Meet the LifeTrak Zoom HRV: a wrist-worn watch that serves as an intensity and recovery trainer. It measures HRV to help you train the right way. It can be worn on the ankle, wrist, or forearm. The device has up to 5 days of battery life and a waterproof design, making it ideal for swimmers.
Wear this on the ankle for cadence analysis while cycling. Zoom is also a sleep analysis tool. It monitors your fatigue and recommends how hard to push your body.