Hypothetically, if the threshold is normally -60mV, but now we have too much calcium on board, our threshold is now -50mv. That is a difference of 40mV that the cell has to account for in order to depolarize. In skeletal muscle, this can cause weakness, fatigue, etc. Too little calcium will cause the threshold to become more negative (gets closer to the resting membrane potential).
OK, this is probably going to come with you laughing at me... Once in a while I wake up with the back of my head sweating, and it`s more common when I take a nap during the day.
If you experience waking up sweating more often than you used to, you may be suffering from sleep hyperhidrosis. Night sweat usually occur at night even when ambient temperature is cool. It can happen anytime when one is asleep, then suddenly waking up sweating and feeling very hot. It can be distressful and can lead to insomnia. This condition is different from flushing, which can also occur during daytime.