Adding weights to the limbs tends to increase wear-and-tear on the tendons and joints. The weight also modifies the moment of inertia of your limb, which puts it in an unnatural position. If you want to do cardio with weights, try using a weight vest. A 20lb weight vest will do the trick. Just know that doing general cardio with impact related movements (such as running) increases your risk of overall injury (particularly at the tendons and joints). If you want to do cardio with weights, do a circuit - it's much safer. If you want to hike, just hike. Hiking with weights isn't really going to increase your performance so much as it is likely to injure you (due to unnatural gait especially). I wouldn't suggest utilizing ankle/wrist weights to most people in general, but I especially wouldn't use them on rest days. If you are recovering from a previous workout, your body will be strained already.