I have experienced something similar to that.  I have an air mattress that I have to inflate every night.  When I turn on the pump the stb that is plugged in the same wall outlet as the fan freezes severly.  Other than that the stb only freezes during some updates, and those freezes are happening with less frequency.  Try plugging the treadmill into a grounded outlet if you have one.  If not and the ac plug on the treadmill is three pronged, try using a ground lift and run the cable into another room.