Healthkit will pool data like weight and blood pressure which is currently being collected by numerous apps available on iPad or iPhone. Apple also announced an app named Health which will be an important inegral part of its future version of mobile iOS named iOS 8.
Apple will work with Nike and Mayo Clinic for its Healthkit app. Both these companies are top names in fitness and health.
Apple has not commented in detail about the capabilities of Healthkit but it is definitely an area which has huge potential in future. And Healthkit will provide an excellent platform for sharing information related to fitness and health.