Is it safe to keep laptop plugged in, even though it's not charging?

I have a Lenovo Z500 and as part of the Lenovo Energy Management software, I get to chose between two "Battery Modes". These are "Maximum Battery Life" and "Optimized Battery Health". When I chose the latter, my laptop only charges till 60% and then it doensn't go any further. Hovering the cursor above the battery symbol displays "… Plugged in, not charging"…
Also, my laptop battery is a non-removable one.
My question is, is keeping the laptop in such an energy saving mode equivalent to keeping a laptop with removable battery plugged it, with it's battery REMOVED?
Can I game for long hours(4-5 hours) without worrying about the battery's health?

SOMETIMES IT IS OK BUT NOT EVERYTIME BECAUSE POWER IS STILL RUNNING THROUGH SYSTEM AND IT COULD HARM YOUR SYSTEM