Brief Answer: you can have cramps and spasm Detailed Answer: Hello, Thanks for your query. I want to tell you that water is must for muscle functioning. Basically it is the medium in which all activity of body take place. If there is lack of water then cell start to shrink. Also there is lack of electrolytes in body. So less salt causes muscles to go in spasm. If there is very severe dehydration then tetany can occur. In this condition muscle become so spastic that it almost unable to relax. If tetany occurs in breathing muscles then patient can die. Maintain good hydration is not possible by water alone. You must take salt also so water remain inside the body . I hope this answers your query. Let me know if you want to ask any thing else.

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