Leg Cramps: Why They Happen & How to Defeat Them

Have you ever experienced the sudden, painful seizing of a leg cramp? Ranging anywhere from a few seconds to a few minutes, the onset is typically rapid, and can occur during exercise, sleep or at rest. Whilst a cramp can come and go, they are normally pointing to a larger imbalance occurring within your body. Let’s have a look at three reasons you may be getting leg cramps, and what you can do to avoid them.

1. Magnesium deficiency

The first, and perhaps biggest reason cramps can occur is due to a magnesium deficiency.[¹] Within muscle cells, calcium works to contract muscle fibres, and magnesium triggers them to relax. If your body does not have enough magnesium, your muscles are able to contract but struggle after this to relax. This prolonged contraction then manifests as the stabbing and intense experience known as a muscle cramp.

The primary reason this deficiency arises is dietary intake. Incredibly, up to 30% of Australians aren’t consuming enough magnesium on a daily basis.

Incredibly, up to 30% of Australians aren’t consuming enough magnesium on a daily basis. 

This is due to the average Australian diet being low in magnesium rich foods wholefoods, as it is often high in refined and processed foods. Instead, magnesium is best sourced from green leafy vegetables, legumes, nuts, seeds, and whole grains.[²]  Magnesium supplementation is also recommended as it has been shown to improve muscle relaxation[³],[⁴],[⁵] 

There are also a number of factors in your lifestyle and environment that that can also cause a deficiency, or increase your body’s demand for magnesium. To learn more about these factors, read our blog ‘10 reasons you need magnesium’

2. Exercise 

Whilst there are countless benefits to regular exercise, muscle cramps are one of the most common side effects experienced from being active. This is primarily due to the sweating that occurs, which not only depletes water levels within the body, but levels of electrolytes too.

Electrolytes are a collection of minerals made up of sodium, potassium, chloride, calcium, phosphate, and magnesium. These minerals dissolve into the water in your body, where they ensure your nerves, heart and muscles work properly, and oversee the passage of fluids in out of your cells. As they’re found within water in the body, profuse sweating not only leads to water loss, but electrolyte loss too. 

This means, beyond the need to rehydrate, a big workout can deplete you of the minerals, such as magnesium and sodium, which your nerves and muscles need to contract and relax properly

Consuming a quality electrolyte formula when you exercise, especially one that contains magnesium, may then diminish your chance of experiencing cramping.

Overtraining can also cause leg cramps. When your muscles are contracted vigorously and repetitively (such as during a spin cycle class), this doesn’t allow for adequate recovery, and cramps may result. To reduce cramping from overexertion, stretch frequently, modify the intensity of your exercise regimen, and schedule in rest days to allow your muscles to recuperate.

3. Prolonged sitting or standing

Your body is designed to move, rest and recover, then move again. When you spend all day seated at a desk or standing for hours on end, leg cramps can occur due to lack of movement. To prevent this, simply stretch your muscles regularly, go for a walk, or break out some star jumps – do whatever you feel like, just get those legs moving!

Don’t let cramps cramp your style!

You can reduce your chances of experiencing leg cramps by consuming magnesium-rich foods, replenishing your electrolytes after exercise, and ensuring frequent and varied movement throughout your exercise and daily routine. A magnesium supplement can also be a great way to quickly replenish your levels of this nutrient if deficient. Finally, I’d recommend speaking to a Practitioner if you’re experiencing severe or prolonged leg cramps, as they’ll address the underlying triggers, allowing your leg cramps to be a thing of the past!

[1] Braun L, Cohen M. Herbs and natural supplements: an evidence-based guide. 4th ed. Vol 2. Sydney (AU): Elsevier/Churchill Livingstone; 2015. p. 677-692.

[2] Schwellnus MP. Cause of exercise associated muscle cramps (EAMC)—altered neuromuscular control, dehydration or electrolyte depletion?. British journal of sports medicine. 2009 Jun 1;43(6):401-8. doi: 10.1136/bjsm.2008.050401

[3] National Institutes of Health. Office of Dietary Supplements. [Internet] [updated 2018 September. Cited 2019 February 26]. Available from: https://ods.od.nih.gov/factsheets/magnesium-healthprofessional/#en1

[4] Braun L, Cohen M. Herbs and natural supplements: an evidence-based guide. 4th ed. Vol 2. Sydney (AU): Elsevier/Churchill Livingstone; 2015. p. 677-692.

[5] D’Angelo EK, Singer HA, Rembold CM. Magnesium relaxes arterial smooth muscle by decreasing intracellular Ca2+ without changing intracellular Mg2+. J Clin Invest. 1992 Jun 1;89(6):1988-94. doi: 10.1172/JCI115807.

[6] Sills S, Roffe C, Crome P, Jones P. Randomised, cross-over, placebo-controlled trial of magnesium citrate in the treatment of chronic persistent leg cramps. Medical Science Monitor. 2002 May 15;8(5):CR326-30. PMID: 12011773

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