Pick a fun activity that gets you fit as a side effect. Mine was rock climbing, but cycling, snowboarding, surfing or pretty much anything will work, provided it is captivating, addicting and you genuinely consider it fun. Eventually you'll want it to be the thing that takes up your weekends and that you find yourself booking flights to unexpected places just because that's the place where the best "X" is. But nobody…
It's great you've found something you enjoy what if you're just not into the outdoors?