answered Mar 23, 2010 at 02:18PM
Dehydration is a lack of fluid.
Excess sweating can cause that lack of fluid & since sweat contains sodium (salt), & excess loss can cause a deficiency- such deficiency can cause fatigue & muscle cramping (as early less severe symptoms)
Sweating is associated with activity; temperature & humidity; so these factors (along with symptoms) will help determine if you require salt tablets; normally salted foods should suffice as long as heart disease, hypertension & edema (fluid) are not present.
If present any salt may have to be restricted-per instructions from a local physician
(someone aware of local conditions).