There has been a lot of debate over whether or not calcium contracts or relaxes muscles. So I thought I would re-post this write up I did earlier for a better explanation and evidence. Especially in light of the lady who reported muscle cramping from drinking the alkalinizing drink with lime (calcium hydroxide) water.
Hopefully she will see this.
Calcium is a muscle contractor. Need more proof? Let's start with rigormortis. The process of muscle movement involves an exchange between calcium, the contactor, and magnesium, the relaxant. If I want to move my hand towards my face the muscles in the upper arm that need to pull the lower arm up influx with calcium causing them to contract, while the opposing muscles influx with magnesium, causing them to relax. If I want to extend the arm back out the muscles that just contracted by the influx of calcium now influx with magnesium causing them to relax, and the opposing muscles that were relaxed by the influx of magnesium now contract by the influx of calcium, which allows the arm to be pulled back the other way. This is very basic anatomy and physiology and has been well known for a long time by everyone with even basic training in medicine. Now that we all are aware of this basic principle, let's get back to rigormortis. When a person dies there is an influx of calcium in to the muscles causing them to contract tightly (rigor). Because magnesium can no longer enter the muscles to displace the muscle contracting calcium, the muscles stay in this contracted state (rigormortis) for several days until enzymes finally start breaking down the muscle tissue.
Then there is more evidence in the use of calcium channel blockers (CCBs) to lower blood pressure. In short, calcium causes blood vessels, which are muscles to contract, which leads to an elevation of blood pressure. CCBs work by blocking the influx of calcium, which keeps the blood vessels relaxed lowering blood pressure. Magnesium works in a similar manner to CCBs. Magnesium displaces the calcium causing the blood vessels to contract thereby relaxing the blood vessels. Is this a well known medical fact? You bet it is!!! The treatment for preeclampsia associated hypertension is IV magnesium, which IMMEDIATELY drops the blood pressure by displacing the muscle contracting calcium!
Know why women tend to crave chocolate around menstruation? It is because the high level of magnesium in the chocolate, which helps to relax the uterine muscles. This helps to control severe menstrual cramping. Magnesium supplements can be used for the same purpose. Magnesium supplements are sometimes used to prevent menstrual cramping by displacing the muscle contracting calcium.
Why is magnesium used to prevent migraines? Migraines start with an initial constriction of the blood vessels around the brain. This is followed by a rebound dilation of the blood vessels leading to inflammation around the brain tissue. If the initial constriction of the blood vessels can be prevented then the migraines can often be prevented. Magnesium keeps the blood vessels relaxed, which helps to prevent that initial blood vessels constriction.
Magnesium also helps prevent insulin damage in diabetes, again by keeping blood vessels relaxed.
Why does magnesium help prevent asthma attacks? Because magnesium relaxes the bronchioles, which again are muscles.
“In muscle, increased intracellular calcium concentration triggers contraction while increased intracellular magnesium concentration counteracts this effect resulting in relaxation.”
“Magnesium is also involved in metabolism of ATP which enables release of energy stored in the high-energy phosphate ester bond. It is also a potent vasodilator.”
“Magnesium sulfate, administered into the circulation, is used as a supplement in treating hypertension (high blood pressure) associated with pregnancy.”
“Magnesium sulfate may dilate (relax) blood vessels by competitively preventing the action of calcium to cause muscle contraction, or by contributing to the release of factors that cause vasodilation.”
“Magnesium effects were prevented by the addition of calcium chloride; this is consistent with the theory in which magnesium sulfate causes vasodilation by competing with calcium.”
“Magnesium works with calcium in muscle contraction and relaxation (calcium-contraction, magnesium-relaxation).”
“Addition of magnesium to calcium-containing medium consistently caused endothelium- and cyclic GMP-independent relaxation that was not altered by oxyhemoglobin or methylene blue. Thus, magnesium and calcium elicit reciprocal or mutually antagonistic effects at the levels of both endothelium-derived relaxing factor formation and/or release and smooth muscle contraction. This relation may be of physiological importance, and the possibility that a reduction in circulating magnesium levels could lead to calcium-mediated vasospasm may be of pathophysiological concern.”
The Role of Calcium and Magnesium in Asthma
“Calcium is known primarily for its function as the main mineral component of bones. But calcium has other important functions, some of which are pertinent to asthma. The control of smooth muscle contraction is governed by changes in the intracellular concentration of calcium ions. (1) In the presence of calcium, ATPase is activated to hydrolyse ATP and provides an available energy source for muscle contraction. “
Magnesium is essential in muscle relaxation after contraction. A severe Mg deficiency causes neuromuscular symptoms such as tetany, an extreme and prolonged contraction of the muscles (10) Within the cells of striated and smooth muscles, magnesium is considered a natural calcium antagonist counteracting the adverse effects of excessive intracellular calcium. Excess magnesium blocks calcium entry, while low magnesium levels potentiate the actions of calcium. (11,12) Magnesium also plays a key role in the production of energy which is needed by the chest wall muscles and the diaphragm to perform the work of breathing. In a double blind study, individuals with low magnesium levels had an increase in the power of their respiratory muscles after receiving an intravenous infusion of magnesium. This effect was not seen in healthy individuals with normal magnesium levels. (13)
“Magnesium sulfate, isradipine, and ritodrine are smooth muscle relaxants used for treating preterm labor.”
“Magnesium is involved in calcium function in the body. While calcium is necessary for correct muscle contraction, magnesium is necessary for muscle relaxation.”
“Magnesium is particularly effective for Muscle Cramps which are active when pressure is applied or with exercise.”
“What is less appreciated is calcium's role in muscle contractions; calcium ions flooding into the muscle cells are the heart of muscle contractions. As the muscles contract they fill with calcium ions, in order to relax, the body must remove these calcium ions from the muscle cells. To remove calcium ions our body needs enzymes and energy; central to both is the element magnesium. Think of it like a sea-saw, calcium tenses, magnesium relaxes. When we are anxious our body tenses, calcium ions rush into our muscle cells, when we relax, calcium ions with the assistance of magnesium are removed from the muscle cells.”
“Look at the symptoms of magnesium deficiency: fatigue, insomnia, muscle twitching, irritability, rapid heartbeat, and numbness. They are familiar symptoms for an anxious person.”
Hmmm… Muscle twitching is a symptom of magnesium deficiency. I wonder if they mean muscle twitching as that which occurs with restless leg syndrome? Of course, that is what restless leg syndrome involves.
“Calcium is the tensing mineral, involved in muscle contraction whereas magnesium is the relaxant, assisting in muscle relaxation.”
“Magnesium and calcium act in conjunction to help to regulate nerve and muscle tone. In many nerves, magnesium serves the function of being a chemical gatekeeper; when there is enough magnesium around, calcium is blocked from rushing into the nerve cell and activating the nerve and the nerve is kept in a state of relaxation. If dietary magnesium is inadequate, the gate blocking can fail and the nerve may become overactivated. When certain nerve cells are overstimulated, they send too many messages to the muscles causing them to overcontract. This series of events helps to explain why magnesium deficiency can cause muscle soreness, tension, spasms, cramps and fatigue.”
“The symptoms of magnesium deficiency can impact many physiological processes since this mineral plays such a wide variety of roles in the body. Common symptoms involve changes in muscle and nerve function such as muscle weakness, spasm and tremor. Since the heart is a muscle it can also experience compromised functioning concomitant with magnesium deficiency which can result in arrhythmia, irregular contractions and increased heart rate.”
“In the search for effective treatment of a life-threatening asthma attack, intravenous magnesium infusion has been studied in asthmatic patients because of its potential effect to reverse bronchospasm and improve pulmonary function. To determine whether magnesium sulfate inhibits airway smooth muscle contraction and the possible mechanism of its action, in vitro experiments were performed on rabbit tracheas.”
“Based on the knowledge that ACH and KCl cause Ca2+ influx into the cells and subsequent contraction by acting on different Ca2+ channels, we concluded that magnesium inhibits Ca2+ influx by blocking the voltage-dependent calcium channels.”
“Periodic uterine relaxation in labor relieves the fetus from hypoxia related to sustained contractions. A reduction in intracellular calcium is essential for relaxation.”
“Magnesium and calcium have similar functions and can either encourage or antagonize each other. The role of these two minerals in muscle contraction is complementary: calcium stimulates muscles and magnesium relaxes them.”
“Magnesium deficiency causes constipation (toxicity, malabsorption, colitis).”
“40-60% of sudden deaths from heart attack occur without artery blockage, clot formation or heart rhythm abnormalities, from spasms in the arteries (magnesium is a natural anti-spasmodic) “
“Magnesium deficiency causes spasms of blood vessels leading to high blood pressure.“
“Magnesium Prevents and Treats
“Magnesium is needed for: processing calcium in the body; relaxation of all muscles including the heart during its relaxation phase of the heart beat which helps protect against a spastic heart muscle and irregular heartbeat; eases fibromyalgia symptoms; assists in lowering blood pressure by relaxing the muscle walls of arteries; and may reduce the severity of asthma attacks by allowing relaxation of chest wall muscles. Magnesium improves symptoms of premenstrual syndrome and has shown to aid in reducing complications of diabetes.”
http://www.fibromyalgiarecovery.com/Magnesium.pdf by Elson M. Haas M.D.
“Functions:Magnesium is considered the "antistress" mineral. It is a natural tranquilizer, as it functions to relax skeletal muscles as well as the smooth muscles of blood vessels and the gastrointestinal tract. (While calcium stimulates muscle contraction, magnesium relaxes them.) Because of its influence on the heart, magnesium is considered important in preventing coronary artery spasm, a significant cause of heart attacks. Spasms of the blood vessels lead to insufficient oxygen supply through them and pain, injury, or death of the muscle tissue that they nourish. To function optimally, magnesium must be balanced in the body with calcium, phosphorus, potassium, and sodium chloride. For example, with low magnesium, more calcium flows into the vascular muscle cells, which contracts them-leading to tighter vessels and higher blood pressure. Adequate magnesium levels prevent this.”
“Uses: As time goes on, magnesium is recommended and used in more and more treatments. Prevention or treatment of myocardial infarctions (MIs), prevention of kidney stones, and in treatment of premenstrual syndrome are some important recent uses. Magnesium has been used with some success in relieving certain kinds of angina and reducing the risks of coronary artery spasms, which can lead to angina or, more severely, heart attack. Deficient magnesium levels have been found in the blood and hearts of cardiac victims. Besides preventing heart attacks, magnesium has a mild effect on lowering blood pressure and so is used to treat and prevent hypertension and its effects. Magnesium supplementation can reduce many of the symptoms of mitral valve prolapse, such as palpitations or arrhythmias, and it may help in other cardiac arrhythmias such as atrial tachycardia or fibrillation, or those caused by taking excess digitalis, a cardiac drug. It may also reduce the bronchoconstriction in asthma by relaxing the muscle around the bronchial tubes. Intravenous solutions containing magnesium and other nutrients have been used successfully to break acute asthma attacks. Magnesium sulfate has been used specifically to lower blood pressure in pregnant women with preeclampsia, which is characterized by edema, hypertension, and hyperreflexia. These problems could become more severe and lead to seizures (then termed "eclampsia") as well. Magnesium sulfate also acts as a mild anticonvulsant in this case. Through its nerve- and muscle-relaxing effect, magnesium may be helpful in reducing epileptic seizures caused by nerve excitability.”
“Early symptoms of magnesium deficiency can include fatigue, anorexia, irritability, insomnia, and muscle tremors or twitching. Psychological changes, such as apathy, apprehension, decreased learning ability, confusion, and poor memory may occur. Tachycardia (rapid heartbeat) and other cardiovascular changes are likely with moderate deficiency, while severe magnesium deficiency may lead to numbness, tingling, and tetany (sustained contraction) of the muscles as well as delirium and hallucinations.
Arterial spasm, specifically of the coronary arteries, is a significant recent concern with magnesium deficiency. This could lead to angina symptoms or even a heart attack. Blood pressure can rise with magnesium deficiency, while an increased likelihood of kidney stones and other tissue calcification is possible.”
“What happens when there are low levels of magnesium? Early on, there are no outward deficiency signs, yet the damage is occurring internally. A consistently low magnesium level will cause an increase in calcium. With more calcium, the heart muscle may have a sustained contraction lasting longer than it should. This could increase the risk of vasospasm (coronary artery contraction, which is spasmodic). This could interfere with blood supply and thus decrease the oxygen supply to the heart. This could cause angina or a high diastolic blood pressure. The bottom number of a person’s blood pressure is the diastolic number. Example: 120/80. Eighty is referred to as the bottom number. This number is elevated when the heart cannot relax during the resting stage of the heartbeat. If the calcium levels get even higher (due to a depleted magnesium level) a systolic rise in blood pressure may occur. This is the top number (120). This rise is due to an intensified contraction of the heart much more than normal. This type of hypertension is treated very successfully with calcium channel blockers, by blocking the uptake of calcium in the heart. “
“The good news is that optimal levels of magnesium, potassium, and manganese act as natural calcium channel blockers requiring less prescription medicine to be needed and given.”
“What other symptoms are present with a magnesium deficiency? Most common symptoms include generalized muscle spasms or nocturnal leg cramps. Premenstrual symptoms greatly improve with magnesium therapy along with vitamin B6. This therapy should be started one week prior to menstruation. An appropriate level would be 400-600 mg of magnesium with 100 mg of B6 orally. Other conditions attributed to low magnesium are asthma, insomnia, migraine and cluster headaches, kidney stones, and calcium deposits in the joints. Think of magnesium as relaxing the tension in your body and on the blood vessels. Your body is stressed during an asthmatic attack and during a headache. The calcium stones may occur secondarily because of a low level of magnesium. A triad disease called syndrome X has low levels of magnesium. This syndrome includes diabetes, obesity, and hypertension.
Urinary frequency can occur in low magnesium patients, because the bladder does not relax (similar to the heart) and therefore cannot hold its normal volume. Bacterial infections are more frequent in patients with low magnesium. This is one reason diabetes have more difficulty with wound healing.
The colon, like the bladder and heart, may have irregularities in contraction and relaxation resulting in constipation. The type of magnesium given for constipation is magnesium sulfate, which is different than when you’re boosting systemic magnesium. It is preferable to use magnesium glycinate or fumerate to elevate the body’s magnesium level. “
Good article on the suject, including a discussion of muscle cramping from magnesium deficiency:
“Therefore, directly acting vasodilators like magnesium (Mg2+) and some organic calcium antagonists, which have, been reported to selectively dilate uteroplacental vessels, have been advocated in managing preeclampsia (Walters and Redmann, 1984; Altura et al., 1987). Mg2" relaxes placental vessels by increasing prostacyclin production as well as by blocking calcium influx (Watson et al., 1986; Nadler et al., 1987). “
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