Night cramps (often called nocturnal leg cramps) are sudden, painful muscle contractions—usually in the calves or feet—that happen during sleep. They’re common and usually not dangerous, but certain people are more likely to experience them.
Most at-risk groups
1. Older adults
Risk increases significantly with age due to reduced muscle mass, nerve changes, and circulation issues.
2. Pregnant women
Especially in the second and third trimester, due to:
- Changes in circulation
- Mineral shifts (magnesium, calcium)
- Increased pressure on leg muscles
3. People with circulation problems
Conditions like poor blood flow or vascular disease can contribute, including:
- Peripheral artery disease
4. People with diabetes or nerve issues
Nerve damage can make muscles more prone to misfiring:
- Diabetes mellitus
5. People who are dehydrated or have electrolyte imbalance
Low levels of potassium, magnesium, or calcium can increase risk—especially after heavy sweating or illness.
6. Athletes or physically active people
Overuse, muscle fatigue, or long periods of exertion can trigger cramps at night.
7. People taking certain medications
Some medicines are linked with cramps, such as:
- Diuretics (“water pills”)
- Some asthma medications
- Statins (in some cases)
Why night cramps happen
Night cramps are thought to be related to:
- Muscle fatigue
- Nerve excitability during rest
- Reduced blood flow while lying still
