Playing for 3 hours non-stop is a little excessive and can cause
excessive sweating caused by ketosis if you have a fast metabolism like me (not eating enough carbs)
and that isn't a good thing. If you are healthy, there really shouldn't be a terrible smell to your sweat. The smells are toxins being released, which is good, but if you sweat regularily, keep well hydrated and eat properly, you shouldn't smell bad when you sweat at all.