Muscle Cramp: Symptoms and Causes

What Causes Muscle Cramp and How Can You Find Relief

Do you suffer from cramp? Do you experience strong and unexpected muscular spasms, particu-larly in your legs? Maybe you visibly see a muscle knot as the pain kicks in? I use the term “kick” with pun intended. In old slang, a cramp is referred to as a Charley horse. They do kick indeed!

Muscle cramps are common, especially as we age.

Research has shown that one in three adults experience cramp. The big 5-0 appears to be the un-lucky number, reported as the average age of onset. If you’re over 80 years of age, that risk jumps to 50%. If you suffer from cramp, you are not alone.

Sadly, cramps are not fleeting or insignificant in nature. A study published in the journal BMC Family Practice found that 40% of sufferers experienced cramp more than three times each week. One in five described them as “very distressing”; words like unbearable, unmanageable and cruel were used. Unsurprisingly, they’re well-known to negatively impact quality of life.

People report being viciously awoken from their slumber. Muscle soreness can persist for days following a cramp. In fact, you might find yourself more at risk for the subsequent eight hours. This is called the cramp prone state and is particularly associated with exercise. And while these painful contractions are often worse at night, they also happen during the day.

This brings us to a key question…

What is cramp?

To understand how a muscle can cramp we first must understand what a muscle is. There are three different types of muscle: cardiac, smooth and skeletal. The latter is the one involved in the cramping process.

As the name suggests, skeletal muscle attaches to your skeleton, or bones. These muscles work by connecting two bones, one on either side of a joint. Say from your thigh bone to your pelvis or your forearm to your upper arm. Every muscle contains contractable units; “contractable”  because they can contract or shorten, or relax and lengthen. Each muscle has a nerve that innervates it, supplying electricity so the muscle can fire. This gives our muscles power, like flicking on a light switch.

Usually skeletal muscles are under conscious control. To walk, you think and the brain powers up your leg muscles. To write, conscious thought enables your fingers to hold a pen and move it smoothly. To turn your head from side to side, your brain tells the neck muscles to act and provide the required motion.

With cramp, though, involuntary contraction occurs. Suddenly, strongly and without permission!

Why does cramp happen?

This is the million-dollar question!

For years we’ve been told dehydration likely causes cramp. While remaining hydrated is certainly important, there isn’t much evidence to support that theory. However, as a review article pub-lished in the British Journal of Sports Medicine said, research is accumulating to support the “al-tered neuromuscular control hypothesis”. If we break this term down it’s not as complex as it sounds.

“Altered” means changed, modified, disputed.

“Neuromuscular” refers to the nerves and the muscles. If we think back to our light switch, turning up the chat between the nerves and muscles falls into this category.

“Control," as you know, means to command.

Together, this term describes a modification in how the nerves and muscles “talk” and so function.

The nerves are meant to provide just the right amount of electrical current. In cramp, though, they ramp up the supply. It’s like theoretically turning a light switch from its max of 10 to 40. It’s not possible in our every day. You cannot think about creating a cramp and make it happen. But, the body can still make cramp happen. Muscle twitches, tightening, rigidity and pain are the proof.

This makes sense. If your nerves are hyper-excitable and turn the electricity up, the muscles con-tract strongly… They cramp.

What alters how nerves communicate with muscles?

There are a range of reasons why nerve-muscle communications can go awry. Different illnesses can trigger change. We’ll take a look at cramp-inducing conditions shortly. But first, we need to discuss nutrients because they matter to nerve-muscle function.

Nutrients, nerve and muscle health

First, let’s look at the B vitamin family…

Several B vitamins (in particular, B1, B6, and B12) are critical for nervous system health. They’re so important they’ve been given the name, “Neurotropic B vitamins.” Neurotropic meaning they feed, nourish, and promote growth and survival of the nerves.

When combined, B1, B6, and B12 have been shown to improve the fine muscle control required for precision and to calm the pain and sensitivity caused by nerve damage. They do this by helping the nerves that control our limbs… The same ones that can trigger cramp.

Vitamin B1 (Thiamine)

Thiamine is essential in its own right.

As Medline Plus says:

Thiamin helps the body's cells change carbohydrates into energy. The main role of carbohydrates is to provide energy for the body, especially the brain and nervous system. Thiamin also plays a role in muscle contraction and conduction of nerve signals.

In essence, vitamin B1 helps the muscles and nerves to have a civil conversation. As we mentioned earlier, this is required for healthy — not overly enthusiastic — contraction.

Vitamin B1 can be found in brown rice, cooked green peas and lentils, oranges, pecans, pork, spinach, and brown rice.

Vitamin B6 (Pyridoxine)

Have you heard of the term, neurotransmitters?

Neurotransmitters are the nerve’s chemical messengers; they transmit the nerve’s message.

How does this work?

The electricity we talked about earlier travels down a nerve. When it reaches the end, neurotransmitters are released. These neurotransmitters then jump into the synapse and across to the nerve or muscle on the other side. The message they deliver can have one of three effects; they can excite, inhibit or modulate. This means it can fire up, calm down and alter the function of the nerve or muscle it communicates with.

nerve ending

Picture: The nerve, synapse and its neurotransmitters.

Healthy neurotransmitter function requires adequate Vitamin B6. It makes sense, then, that a de-ficiency may contribute to cramp. But does it?

A study investigated cramp in pregnant women. The researchers found that supplementing with vitamins B1 and B6 resulted in significant improvements in the frequency and severity of cramp. While this study was performed during pregnancy, we believe these results are transferable.

Other research suggests they are…

 A study published in The Journal of Clinical Pharmacology investigated whether supplementing with a vitamin B complex could ease night-time leg cramps. The results were stunning!

After three months: “86% of the patients taking vitamin B had prominent remission of leg cramps.”

A significant reduction in the duration, frequency, and intensity of these painful spasms resulted.

Vitamin B6 can be found in bananas, oats, peanuts, pork, poultry, and soya beans.

Vitamin C (Ascorbic acid)

Vitamin C is a powerful antioxidant that supports nerve health. It aids in their survival and is es-sential for producing and modulating neurotransmission. Remember, if the body is to send healthy messages, it needs healthy nerves, synapses and neurotransmitters to do so.

Vitamin C can be found in blackcurrants, broccoli, oranges and orange juice, peppers, and straw-berries.


This incredible mineral has over 300 functions within the body. It is a hidden gem! Known in the natural health world as the great relaxer, its description is spot on. Essential for the regulation of muscle contraction, nerve impulses and neuromuscular conduction (again, how nerves and muscles chat), it has been used therapeutically for an age.

A study published in the journal Medical Science Monitor showed that when supplementing with 300 mg magnesium citrate for six weeks there was a trend towards less cramping, and the partic-ipants reported relief.

Magnesium can be found in baked potato, black beans, brown rice, green leafy vegetables like spinach, legumes, nuts like almonds, cashews and peanuts, and seeds including pumpkin and chia.


Other than being a mineral, zinc has another commonality with magnesium. It, too, is required for over 300 functions within the body. These functions are important to skeletal muscle and nerve health.

As a 2020 article said, zinc deficiency presents with stiffness of the joints and abnormal stride. These changes could be due to muscle, nerve or neuromuscular junction defects. Each of these could, as we’ve seen, be linked to cramp.

And linked cramp and zinc are. A study published in the Journal of the American College of Nutri-tion identified a staggering outcome: "Zinc supplementation improved cramps in 10/12 patients, and in seven of these patients the cramps completely resolved.”

Given there are no pharmaceutical options known to resolve cramp… and that the old medicine, quinine, comes with substantial doubts about its effectiveness and serious, potentially lethal, side effects… This is staggering, exciting and a potential game changer. Yet…

Research has shown that only 55.6% of Americans have an adequate zinc intake. This is based on intakes of only 77% or more of the recommended dietary allowance (RDA); still a little short when considering the recommended intake.

Research suggests that the greatest risk of inadequate zinc intake occurs as we age. People who are older than 71 years consume around 8–10 mg. The RDA is 15 mg.

Zinc can be found in beans, crab, lobster, oysters, nuts and seeds.

Are you getting enough of these key nutrients?

It’s been estimated that 10.5% of Americans are deficient in vitamin B6, 6% in vitamin C, 75% in magnesium, and between 1.5 and 15% in vitamin B12. And as we grow older, the risks increase.

Then there’s zinc… An article published on Oregon State University’s website said, “Even in the United States, about 12 percent of the population is probably at risk for zinc deficiency, and per-haps as many as 40 percent of the elderly, due to inadequate dietary intake and less absorption of this essential nutrient.”

As the authors noted, diet quality often drops as age rises. To make matters worse, the digestive system finds it more difficult to absorb the required nutrients. And required they are. Essential in fact. All the nutrients we’ve discussed cannot be made in the body. They must come from the food we eat or the supplements we take.

Now that you understand the importance of nutrients in relation to cramp, let’s take a look at cramp-inducing conditions.

Conditions that can cause cramp

While nutrition plays a crucial role, there are conditions — both functional and related to illness — that can trigger unwanted muscle cramping. Regardless of the cause, it seems that the underly-ing mechanisms are similar. This includes a shift in the way nerves and muscles talk.

Exercise-Associated Muscle Cramp

Exercise has long been known to trigger cramp. We’ve all watched as our favorite sportsperson has keeled over in pain, frantically trying to stretch out the spasm.

Again, research suggests the cramp associated with exercise aligns with neuromuscular theory, rather than the dehydration.

Writer's Cramp

This type of tightness, often described as cramp, is considered task-specific. As the muscles spasm, the hand can be pulled into abnormal postures and make writing difficult and painful. The usual onset is between 30 - 50 years of age.

Why does it occur? That’s a great question. It seems a specific pathway in the brain is faulty. Again, it comes back to the nervous system.

Amyotrophic lateral sclerosis (ALS)

ALS is a horrid, progressive disease where the nerves slowly degenerate and die, weakening mus-cles and triggering physical dysfunction.

The article Natural history of muscle cramps in amyotrophic lateral sclerosis reported that 95% of people with ALS will experience muscle cramps at some point during the disease journey. One in five have severe cramps more than once per day. Unsurprisingly, this leads to sleep disturbances 50% of the time.

While thankfully this disease is rare, it also points to the hyper-excitable motor nerve theory of cramp.

Cirrhosis of the liver

Muscle cramps are so common in liver cirrhosis they can almost be considered the norm. A 2013 article noted that, “The prevalence ranges from 22% to 88% based on varying definitions of cramps.”

It seems that cirrhosis-induced cramp is related to altered nerve function, changes in energy me-tabolism, and shifts in electrolytes and blood volume. As with other types of cramp, increased muscle-nerve excitability is thought to be involved. Recall, that’s like turning up the electricity coursing through the muscle.

The authors reported that both zinc and vitamin E have been shown to provide respite.

Cramp-Fasciculation Syndrome

This name explains this condition: It is associated with unsolicited, painful cramps and muscle twitches (known as fasciculations).

The usual muscles involved are the thighs and calves, however, muscles in the arms or chest can be involved, too. Muscle stiffness, the sensation of burning or prickling, anxiety, and fatigue may also occur.

As with other cramp, cramp-fasciculation syndrome is thought to be related to abnormal excitabil-ity of the nerves.

Physical activity can bring them on; stretching may provide relief.


An estimated 10.5% of the US population has diabetes, with those rate rising with age. As diabetes progresses, nerve damage can occur. Called neuropathy, it has been linked to cramp.

The study Prevalence of Muscle Cramps in Patients With Diabetes reported that cramp occurred in  a staggering 75.5% of type 2 diabetics and 57.5% of type 1 diabetics. That means millions of people are suffering from cramp due to diabetes in the USA alone!

Why is cramp so common in diabetes?

The study authors found that:

Neuropathy, a risk factor for development of cramps on the basis of peripheral nerve hyper-excitability was found to be the most important factor determining development of cramps in our diabetic cohort.

Again, it appears that the nerves that supply skeletal muscles become overly excited. This ramps up the electrical supply and overly stimulates the contractible parts of the involved muscle.


While one in fifty adults have fibromyalgia, middle-aged women are more at risk. This condition causes body-wide pain, fatigue, depression and anxiety, brain fog, headache and, you guessed it, cramp.

Again, hyper-excitability of the peripheral nervous system — the nervous system that talks to the skeletal muscles — seems to be key.

The Wrap Up

There are additional conditions that are linked to cramp; some common, some rare. But across the board there appears to be a common feature. An excitable nerve or nerves that overstimulate the skeletal muscle or muscles they supply.

The pharmaceutical medication, quinine, has a history of use for cramp. But with its fuzzy efficacy and raft of side effects, its use has been warned against. As MedScape said, “Quinine and Leg Cramps: Not Worth the Risk.”

Thankfully, there is a safer, natural option.

Taking a synergistic combination of nutrients may provide the relief and respite you need. Sup-plementing with vitamins and minerals that have been linked to improvements in nerve and muscle function is important. This improves how these nerves and muscles “talk”. This may work by reducing the hyper-excitability of a nerve and reduce the frequency and severity of cramp.

That’s win-win… Better relief, without significant side effects!