Achieve goals doing less!
When it comes to burning fat, maintaining a good fat to muscle ratio or building muscle your time working out shouldn't be about going through the motions or doing spending 2 hours at low intensity. Personally this is a waste of time and it could be spent outside of the gym living your life how you intend.
1 hour of effective intensity aka hard work should be most peoples aim.
Sweat isn't an indicator of a good workout, it is a response by the body to getting hot and wanting to cool down, automated regulation. We can eat hot food and sweat doesn't mean I've had a good workout at the dinner table.
That 1 hour is massively more effective at achieving goals than 2 hours of going through the motions.
If results aren't being seen or have stopped and you are doing more than 60 minutes the answer isn't to do more but be more effective with your time.
If 2 hours doesn't work i suggest not increasing it. A common thing i come across is people thinking 'more' is the answer. When in fact its the opposite.
Matt