What Are The Adverse Effect On Legs And Torso After Prolonged Laptop Usage?

Just curious if prolonged laptop usage with it resting on my legs could ever cause my upper legs to become sore. Mainly the upper part of the leg where it joins the torso.....Perhaps with the 'heat' radiating from the laptop into my leg muscles for an extended period of time?? 63 y/o-5'8"-210 lbs.-good health..(except for those aching leg muscles!!)