While HGH is fine for your objectives, it is not the best thing. First of all, you need to run it for quite a while (several months) to really start noticing the results. This is quite hard to do, since HGH costs so damn much. Besides, it is extremely hard to find real HGH. All in all, there are too many complications with HGH.
Instead, I would recommend you to run Cardarine GW-501516, as I think it will be ideal for your objectives - it will give an amazing boost in endurance, recovery and cardio. Without any water retention and with some lean gains. Additionally, Cardarine GW is non-hormonal, so there will be no side effects to it, and it is completely safe to use. Just my old man's 2 cents here.