From the Guidelines
Muscle cramps are primarily caused by muscle fatigue, dehydration, electrolyte imbalances, and poor blood circulation, with dehydration and electrolyte imbalances being key factors, as evidenced by the 2018 study on the management of patients with decompensated cirrhosis 1. When muscles are overworked or strained during physical activity, they can involuntarily contract, resulting in painful cramps. Dehydration reduces blood volume, concentrating electrolytes and making muscles more susceptible to cramping. Imbalances in key electrolytes like sodium, potassium, magnesium, and calcium disrupt normal muscle function since these minerals are essential for proper muscle contraction and relaxation. Some medical conditions, such as those involving metabolic or electrolyte disorders, can also contribute to muscle cramps, as noted in the 2019 review on Guillain-Barré syndrome 1. Additionally, certain medications, including diuretics, can lead to muscle cramps due to their effects on electrolyte levels, as discussed in the 2018 guidelines for the management of patients with decompensated cirrhosis 1. To prevent muscle cramps, it is essential to:
- Stay well-hydrated by drinking water regularly throughout the day, especially before, during, and after exercise
- Consume electrolyte-rich foods like bananas, oranges, and leafy greens, or use electrolyte supplements during intense physical activity
- Stretching before and after exercise helps prepare muscles for activity and reduces cramping risk
- For immediate relief when experiencing a cramp, gently stretch the affected muscle, apply heat to relax tight muscles, or massage the area to improve circulation. In cases of frequent or severe cramps, underlying medical conditions like peripheral artery disease, nerve compression, or certain medications might be responsible, warranting consultation with a healthcare provider, as suggested by the 2009 guidelines on parenteral nutrition 1.
From the FDA Drug Label
Magnesium is an important cofactor for enzymatic reactions and plays an important role in neurochemical transmission and muscular excitability. Predominant deficiency effects are neurological, e.g., muscle irritability, clonic twitching and tremors.
Muscle cramps can be caused by hypomagnesemia (low serum levels of magnesium), which may lead to muscle irritability. 2
From the Research
Causes of Muscle Cramps
- Muscle cramps are painful, sudden, involuntary muscle contractions that can be associated with a wide range of acquired and inherited causes 3
- The causes of muscle cramps that occur during or soon after exercise remain uncertain, although there is evidence that some cases may be associated with disturbances of water and salt balance, while others appear to involve sustained abnormal spinal reflex activity secondary to fatigue of the affected muscles 4
- Exercise Associated Muscle Cramps (EAMC) is one of the most common conditions that require medical attention during or immediately after sports events, and the aetiology of EAMC in athletes is still not well understood 5
- Recent evidence suggests that EAMCs are due to a confluence of unique intrinsic and extrinsic factors rather than a singular cause 6
- Water intake after dehydration can make muscles more susceptible to cramp, but electrolytes can reverse that effect 7
Possible Mechanisms
- Altered neuromuscular control is a possible mechanism for the aetiology of EAMC, with scientific evidence based on research studies in human models of muscle cramping, epidemiological studies in cramping athletes, and animal experimental data 5
- Dehydration and electrolyte depletion are also possible mechanisms, although the evidence for these hypotheses is largely anecdotal and not supported by prospective cohort studies 5
- Spinal pathways may also play a role in the development of muscle cramps, with evidence from experimental models involving electrical stimulation or intense voluntary contractions of small muscles held in a shortened position 4
Risk Factors
- Unique intrinsic and extrinsic factors can contribute to the onset of EAMCs, and individualizing EAMC prevention strategies may be more effective than generalized advice 6
- Patient-specific risk factors, such as medical history and environmental factors, should be taken into account when developing prevention strategies 6