Why exactly does dehydration cause muscle cramps?

Now, I know that when you sweat excessively, you lose a lot of your body's sodium, which is important for a nerve impulse to transmit through a neuron and into muscle tissue. But, I don't understand why the sodium is needed in order for this to happen. Any help would seriously be greatly appreciated. Thanks :)

Question

Why exactly does dehydration cause muscle cramps?

Now, I know that when you sweat excessively, you lose a lot of your body's sodium, which is important for a nerve impulse to transmit through a neuron and into muscle tissue. But, I don't understand why the sodium is needed in order for this to happen. Any help would seriously be greatly appreciated. Thanks :)

aaronq · Answer

I think the simple answer would be that the resting potential cannot be restored, cramps also come from insufficient [$Ca^{2+}$] in muscles needed to activate troponin. This topic is kinda hard to cover here because there is a lot of material, but if you're interested i'd suggest you watch these videos: https://www.youtube.com/watch?v=zopoN2i7ALQ&list=PLbKSbFnKYVY1UizswNtijZpmw678derZE https://www.youtube.com/watch?v=4htSVI5E9AQ&list=PLbKSbFnKYVY34O4gcc5QGcnw_7PbS89Wq