There are two parts to this.
If you wear heavy armor, it will lower your stamina regeneration. There are 4 stages of this. If you look up armors on the wiki, there will be tables that show you how many "points" of stamina reduction they give. I'm pretty sure that the torso gives 2 points and the rest gives 1 point.
If your equip burden is above 50%, your movement and rolling speed will be lowered. There is no affect on stamina regeneration (unless you are wearing heavy armor).
So, if your Endurance was 10, and you wore light armor that took your equip burden above 50%, you would move slower, but have no penalty to stamina regeneration. However, if your Endruance is 40, and you're wearing heavy armor but your equip weight is NOT above 50%, you will move at normal speed, but still have a penalty to stamina regeneration.
Hope this helps.
