How hot are we talking here? Truly hot or just very warm? Is it hot enough to fry an egg? Does it burn your hand? Is it too hot to tolerate while holding it causing you to have to set it down? What apps are you running when it gets hot?
6-8 hours of usage is good. 6-8 hours of standby is not. Which were you referring to? Does it get hot during normal usage with apps such as email, messages and safari or does it only get that hot during intense games?
Try a hard reset. If that doesn't work, restore it. If it still does it you'll need to take it to Apple to have the battery checked.
If it truly gets so hot you can not hold it in your hand, DO NOT keep charging it. In all honesty I wouldn't even have it inside my house.
That's the retired Firefighter in me speaking.
If it is getting warmer than usual, follow what @Europa said to try.
You should probably take it in to Apple if you have one nearby, or take it to an authorized seller to get it looked at, but only if it continues to occur often.
I have not had this happen on any of my iPhones besides when it was in the sun. Now, my laptop is a completely different story. It is normal for a laptop to heat up when watching a video or playing a game.
My iPhone 4s fell 3 meters onto concrete surface. It still works
On the same day the iPhone updated the IOS 7 version
Now my phine gets extremely hot that i cannot hold it, when charging
This has never happened before
Could it be from the fall or the update
U speak of doing a hard reset
How does one accomplish reset
See also several posts on a similar thread "iPhone Overheating"....
Glad you tracked down the issue, as 'warm' is certainly acceptable and normal in many situations. But 'hot' however it is defined , indicates something's amuck somewhere, and can be dangerous in a few cases. I'm also a great '4s' fan