I am seasoned in writing software and product design. I know healthcare is a very promising field but I don't have good knowledge of the industry. Some similar consumer wearables in healthcare would be the fit bit, a glucose meter or a heart rate monitor.
Focus on apps/devices that make it easier to manage chronic diseases--asthma, COPD, diabetes, or other issues like infertility.
Managing these ailments can be cumbersome, and most patients fail at managing them. This is where mobile devices can offer the most benefit.