Do heavy darts make you tired after long play?

Hello.

I'm only recently learning how to play darts, I have played before but just throwing at the board with no real thought about how to get better. I have owned many sets of darts, and have tried all different weights.

I don't know what weight to use right now. I like the heavier darts but my aim gets worse the longer I play. I think it may be fatigue (even though I don't actually feel any.)

Is that actually a thing? Should I just keep pushing on with the darts the feel right and the issue will get better over time?

Anyone else experience such a thing?