Winner, winner, let's get thinner!

I'd love to be able to keep a track on my fitness, my daily steps and my heart and pulse. At nearly 73 I need to improve my fitness in order to live a long and healthy life. My grandma lived to be 101, my uncle was almost 102 and my remaining aunt is nearing her 99th birthday! I'm hoping to follow in their footsteps. None of the fit watches I've bought before have been rubbish, one even counted my steps when I was sitting knitting! I need the daddy of watches please, either will be great, thanks for the chance