Most of the time, there's no known cause for night leg cramps. In general, they're likely the result of tired muscles and nerve problems.

The risk of having night leg cramps increases with age. Pregnant people also are more likely to have night leg cramps.

Kidney failure, diabetic nerve damage and problems with blood flow are known to cause night leg cramps. But if you have one of these conditions, you probably already know. And you likely have symptoms other than just night leg cramps.

People who take medicines that increase urine output might be more likely to have night leg cramps. But it's not known if there's a direct link.

Restless legs syndrome is sometimes confused with night leg cramps. But the conditions are different. The most common symptom of restless legs syndrome is the need to move the legs when falling asleep. Restless legs syndrome is usually not painful, and the symptoms last longer than do night leg cramps.

Other health issues that can sometimes be linked to night leg cramps include:

1. Acute kidney injury
2. Addison's disease
3. Alcohol use disorder
4. Anemia
5. Chronic kidney disease
6. Cirrhosis (scarring of the liver)
7. Dehydration
8. Dialysis
9. High blood pressure (hypertension)
10. Hyperthyroidism (overactive thyroid) also known as overactive thyroid.
11. Hypoglycemia
12. Hypothyroidism (underactive thyroid)
13. Lack of physical activity
14. Medicines, such as those used to treat blood pressure problems and high cholesterol, and birth control pills
15. Muscle fatigue
16. Parkinson's disease
17. Peripheral artery disease (PAD)
18. Peripheral neuropathy
19. Pregnancy
20. Spinal stenosis
21. Type 1 diabetes
22. Type 2 diabetes