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.
This condition occurs when the glucose (sugar) levels in the blood are lower than normal. Hypoglycemia will cause headaches at night accompanied by night sweats. You can counteract the hypoglycemia by eating a small snack just before bedtime. This snack should be light but balanced to regulate your blood sugar levels.