The faster the refresh rate, the faster the horizontal sweep rate, which causes the horizontal output transistor to run hotter, and the amount of extra heat increases slightly more than the increase in horizontal rate because it takes time for the transistor to turn on and off, and that's when most of the power is dissipated.
I think it's a lot better to run a monitor at no faster than the 2nd highest horizontal rate or slower, especially if it wasn't made by a Japanese company.