What type of armor you can wear without getting tired(running slower) is determined on strength and dexterity. Heavy armor might not all ways be the best choice as it make you slow and running away is much harder especially with a backpack.Travelling becomes harder and slower and you will slow down the team.
But when it comes to combat the armor does it job. Heavy armors are expensive or can be crafted through Heavy armor smithy .
TIP(I found some good heavy armor in cannibal planes a lot)