Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Muscle Cramps


The Manual's Editorial Staff

Reviewed/Revised Sep 2021 | Modified Sep 2022
Get the full details
Topic Resources

What are muscle cramps?

Muscle cramps are pain in your muscles when they suddenly tighten. Muscle cramps last from a few seconds to several minutes.

  • Muscle cramps usually come on without warning

  • Muscle cramps are common in healthy people, especially middle-aged and older people

  • Cramps can happen during or right after hard exercise, or while you're in bed at night

  • Muscle cramps very rarely are a symptom of a nerve problem

What causes muscle cramps?

When should I see a doctor for muscle cramps?

See a doctor right away if you have muscle cramps and any of these warning signs:

  • Cramps in your chest, arms, or belly

  • Weakness or losing feeling in parts of your body

  • Muscle twitches

  • Cramps started after you lost a lot of body fluids from throwing up, sweating a lot, having diarrhea, or taking diuretics (medicine that makes you urinate [pee] more)

Call your doctor in 1 to 2 days if:

What will happen at my doctor visit?

Your doctor will ask about your symptoms and do a physical exam.

Sometimes, doctors will do blood tests to check for other problems that can be causing your symptoms.

How do doctors treat muscle cramps?

If your cramps are caused by another health problem, doctors will treat that problem.

If your cramps are the harmless but painful kind, you can relieve them by:

  • Stretching the muscle

For example, if the cramp is in your calf, stretch your calf by pulling your toes up toward your head (the runner's stretch).

Runner's Stretch

If you get a muscle cramp in your calf you can stretch the muscle by using your hand to pull your foot upward or by doing a runner’s stretch:

  • Stand with one leg in front of the other with both heels touching the ground

  • Place your hands on a wall for balance

  • Gently bend the knee of your front leg until you feel a stretch in the back of your other leg

  • Hold this stretch while you count to 30, then relax and straighten the knee of your front leg

  • Repeat the knee bend and stretch for a total of 5 times (for each leg)

  • Switch so that your other leg is now in front, then repeat the knee bend and stretch again

How can I prevent muscle cramps?

  • Gently stretch your muscles before you exercise or go to bed

  • After you exercise, drink water and other fluids (especially sports drinks, which have electrolytes)

  • Don’t do a lot of hard exercise right after you eat

Drugs Mentioned In This Article

Generic Name Select Brand Names
Calcidol, Calciferol, D3 Vitamin, DECARA, Deltalin, Dialyvite Vitamin D, Dialyvite Vitamin D3, Drisdol, D-Vita, Enfamil D-Vi-Sol, Ergo D, Fiber with Vitamin D3 Gummies Gluten-Free, Happy Sunshine Vitamin D3, MAXIMUM D3, PureMark Naturals Vitamin D, Replesta, Replesta Children's, Super Happy SUNSHINE Vitamin D3, Thera-D 2000, Thera-D 4000, Thera-D Rapid Repletion, THERA-D SPORT, UpSpring Baby Vitamin D, UpSpring Baby Vitamin D3, YumVs, YumVs Kids ZERO, YumVs ZERO
quiz link

Test your knowledge

Take a Quiz!