There are those who swear by salt tablets, and there are those who swear against them. There are those who swear by 'sports drinks' for the salt and other 'electrolytes' in them, and there are those who sneer at them. There are those who believe in the recent fad for drinking huge volumes of water, and there are those who never do it and think it is dangerous (which it is).
Water makes up around 60% of the total body weight, and major reductions impares normal body performance
Sweat contains the following electroyltes - Sodium, Chloride, Calcium, Potassium and Magnesium - technically these are all salts
Many ... sports drinks contain the above electrolyte to a similar concentration as normal sweat - however the sodium concentration is often HIGHER than the sodium concentration in blood. Sodium (in salt as we know it) absorbs water, and is discharged through the body. Therfore excessive levels of sodium found in sports drinks actually blocks the absorbtion of water in the body.
These electrolytes are best managed by eating a healthy balanced diet,
The Australian Sports Commission and Australian Institute of Sport advise that it is not possible to drink too much water [WRONG] as the body will dispose of what is not necessary. HOWEVER, if a person slips into shock from dehydration water CAN be fatal [true] (follow normal shock proceedures - sipping, moisten lips etc)
I recommend to athletes to begin hydration well before training - 2-3 hours. For high performance I recommend begining hydration before going to bed the night before, drinking plenty of water before sleep and then a further 2 litres on waking. Sure this causes heavy peeing but the body is fully hydrated then for a full days training. I follow similar guidelines before my own training.
The causes of cramps are multi-factorial:- cramps occur in conjunction with heat, cold, dehydration, low blood sodium and/or potassium (& probably other eloctrolytes), fatigue, low blood sugar, high intensity (anaerobic) weight training, low intensity (aerobic) training, etc.
Sometimes cramps occur for no apparent reason (like the cramps I get in the arch of my foot in the middle of the night).
There is great individual variation in cramping - both between individuals experiencing the same conditions, and over time by an individual experiencing the same conditions.
There is no 1 solution to cramping, and many professional athletes continue to suffer cramping despite the assistance of Sports Doctors, Exercise Physiologists, Dieticians and Trainers.
The application of salt (in tablets or drinks) may help some individuals who have a low dietary salt intake, sometimes. However, if the cause of the cramp is not due to low electrolyte levels, electrolytes would probably not assist.