The underlying cause of muscle cramps is not well understood.[1] [1] Much of the evidence is nonscientific or observational.[2]
One hypothesis for the cause of muscle cramps is because of dehydration and/or electrolyte abnormalities. However, trials have shown no significant correlations between hydration, serum electrolyte levels, and muscle cramps.[3][4]
A stronger hypothesis may be muscle fatigue and nerve dysfunction, and would help to explain why muscle cramps can occur after changes to exercise (e.g., unusually high volume or intensity, or unusual heat or humidity in the environment).[4]PMID:33998664]
The cause may ultimately be multifactorial. People with muscle cramps should be examined by a licensed healthcare professional to explore the above potential causes, along with more rare causes of muscle cramps, such as:[5]