I meditate almost daily for roughly 2+ hours and during that period I can feel waves of heat passing through the entire body. The solar center is located just b

I meditate almost daily for roughly 2+ hours and during that period I can feel waves of heat passing through the entire body. The solar center is located just below the navel. If you focus in the naval area you can generate heat. I don't practice to generate heat but certainly see that as a side effect. I wonder if these Monks and Yogis can stay warm the entire day or just during the meditation practices