magnesium for fitness

Magnesium for Fitness, Exercise Performance & Recovery

Table of Contents

Are you getting enough magnesium for fitness?

According to Dr. Carolyn Dean in The Magnesium Miracle, “Even though most athletes and coaches don’t know it, magnesium is one of the most important nutrients athletes can possibly take.” (Kindle version, page 2096).

Your body needs magnesium for sleep, energy, stress management, mood regulation, brain health, strong bones, healthy blood sugar, inflammation, and more. Yet few people realize that magnesium is also a key mineral for fitness.

Whether you’re a dedicated athlete, or you exercise purely for fitness, magnesium can make all the difference in your performance and endurance.

In this post, we’ll take a deeper dive into how magnesium can give you more energy and reduce exercise-related pain. We’ll also look at why overlooking magnesium can put active people at risk for chronic and acute symptoms of magnesium deficiency.

You need enough magnesium to produce energy for exercise

Magnesium is often referred to as “the sleep mineral” or “the original chill pill” because it helps so much with sleep and stress. Yet magnesium is an energy nutrient, too, even though it acts as a relaxant and not a stimulant.

Here’s how it works:

Together with B-complex vitamins, magnesium activates enzymes that control digestion, absorption, and the utilization of proteins, fats, and carbohydrates…

Of the 700-800 magnesium-dependent enzymes, the most important enzyme reaction involves the creation of energy by activating adenosine triphosphate (ATP), the fundamental energy storage molecule of the body.”  (The Magnesium Miracle, p. 15)

Magnesium bonds with ATP to produce energy packets for our body’s vital force. Without magnesium, we can’t produce or store energy. (The Magnesium Miracle, p. 14-15)

So, if you are feeling low in energy and it’s affecting your workout, consider whether you’re getting enough magnesium. See our guidelines below on magnesium requirements. To boost your daily intake, try our topical magnesium products

Do you know someone who would love to workout, but just can’t find the energy? They may be magnesium deficient. Share this post to let them know!

Feeling the lactic acid burn after exercise? You may be low in magnesium

Exercise-induced muscle pain comes from lactic acid, a normal byproduct of muscle metabolism. It’s the short-term burn you feel when you push your muscles past your comfort zone.

Lactic acid peaks during exercise and can linger for up to about a day. If you exercise intensely or have chronic fatigue syndrome, you’ll feel the burn more than others.

In good news, magnesium helps neutralize lactic acid.

Magnesium allows the body to burn fuel and create energy in an efficient cycle during exercise that does not lead to lactic acid production and buildup,” (The Magnesium Miracle, Kindle version page 2115).

A 2006 study on 30 male athletes found that magnesium supplementation helped to lower lactic acid levels.

Do you know someone who subscribes to the ‘no pain, no gain’ school, and lives with persistent, exercise-related pain? Tell them about magnesium and lactic acid.

Magnesium reduces inflammation from Delayed Onset Muscle Soreness

That ache in the morning after a good workout can be a good feeling because you know you’ve pushed yourself.  If you can’t walk or move properly, though, delayed onset muscle soreness (DOMS) can be a problem.

This type of soreness usually occurs as a result of one of these things: muscle tension, muscle overuse, mild muscle injury, or skipping warm-ups and cool-downs. DOMS can weaken muscles and decrease your range of motion.

While lactic acid only remains in your muscles for a few hours after your workout, DOMS usually occurs between 24-48 hours after your workout. 

DOMS is believed to be a result of microscopic attrition to muscle fibers, which creates the stiffness and soreness you feel in the following days. These micro-tears cause an increase in blood flow and inflammation to the area, which makes the area more responsive to movement by stimulating the pain receptors within the muscle tissue.  

Magnesium reduces inflammation, and thus can downgrade post-exercise DOMS pain. A 2021 study on the effects of magnesium supplementation on muscle soreness and performance found that magnesium supplementation (350 mg/day for 10 days) significantly reduced muscle soreness at 24, 36, and 48 hours. Subjects also perceived improved recovery.

Magnesium reduces exercise pain and helps you recover faster

Other forms of exercise-related pain get downgraded by magnesium, too.

Magnesium prevents post-exercise cramps and pain and indirectly relieves pressure on nerves that would otherwise be compressed by tense muscles.

How does it work?

Magnesium regulates the process whereby muscles contract (via calcium) and then relax. Without magnesium, “muscle cells stimulated by too much calcium can go into uncontrollable spasm” (The Magnesium Miracle, Kindle version page 173).

What type of spasms? Any type of cramping of a major muscle can be a spasm. Spasms can even cause tension headaches.

Learn more about exercise pain and magnesium in the story by Dr. Tanner below.

Exercise depletes your magnesium levels

Exercise is a form of stress – albeit a healthy form – and as such, exercise speeds up our magnesium burn rate. The effort involved in muscle contraction, respiration, and energy production places a big demand on our magnesium stores.

When you push past a “wall” of fatigue, you use up adrenaline. You are, in effect, pushing your adrenal glands to the max and using up magnesium in the process. (The Magnesium Miracle, p. 72)

Also, when we exercise, we literally sweat out magnesium. In fact, endurance athletes sweat 1 to 1.5 liters per hour.

It’s important to remember that magnesium is a water-soluble mineral. Even without sweat, we excrete magnesium daily. Add a good workout and you begin to leech magnesium through your pores.

Under certain conditions, exercising hard and sweating excessively without enough magnesium can lead to dangerous symptoms. Watch out for blurred vision, muscle twitching, spasms, confusion, agitation, hallucinations, nausea, and weakness. These can be precursors to more serious events including seizures and sudden cardiac death syndrome.

The good news is, you don’t need to cut back on exercise to get your magnesium in balance. You can easily replace the magnesium lost through exercise with a good supplement, like Bolton’s Naturals Topical Magnesium Spray or Gel

Exercise performance enhancers can leave you low in magnesium

If you fuel your workouts with ‘performance enhancers’, you may actually be depleting your magnesium. Common workout-enhancing drinks and food supplements that tap into your magnesium reserves include:

  • Caffeine
  • Sugar and sodium in sports drinks, “electrolyte replacement drinks”, sports gels, sports bars
  • Protein bars and shakes loaded with calcium

All of these use up magnesium in metabolism. And it can become a vicious cycle:

The more you deplete your body of magnesium, the more help you’ll need to sustain a high level of activity. If you turn to caffeine and the wrong kind of sports supplements, your magnesium levels will plummet further.

Worried you won’t be able to work out without stimulants and protein loading? You don’t need to.

If you correct a magnesium deficiency, your body will become more efficient at producing energy, and metabolizing carbohydrates, and proteins. You’ll feel more energized, naturally.

(Not convinced? See Dr. Tanner’s marathon story, below.)

Also, please stay away from diuretics. Combined with exercise, diuretics can be dangerous because they increase your rate of magnesium loss – just when you need it most, and can put you at risk for heart issues.

Magnesium deficiency may cause sudden cardiac arrest during exercise

First, let’s put the risk in context: Sudden Cardiac Arrest while exercising is rare.

Here’s how rare: In a study published in the medical journal Circulation, investigators studied over 1,000 people aged 35-65 who had experienced a sudden cardiac arrest. Just 5 percent had a sudden cardiac arrest during sports activities. (Cedars-Sinai)

In many cases, Sudden Cardiac Death (SDC) during exercise happens because of an existing heart condition – known, or unknown. In other cases, SCD may be caused by a sudden interruption in the heart’s rhythm.

The body is electric”, as Dr. Carolyn Dean reminds us in The Magnesium Miracle. Magnesium transmits electrical impulses within the heart’s cells and influences the rhythm of contraction and relaxation in the heart.

In Sudden Cardiac Arrest, “the electrical system to the heart malfunctions and suddenly becomes very irregular. The heart beats dangerously fast. The ventricles may flutter or quiver (ventricular fibrillation), and blood is not delivered to the body.”(WebMD)

Dr. Dean cites a study of young, healthy, well-conditioned men, noting that “strenuous effort was reported to give rise to persistent magnesium deficiency and a related long-term increase in cholesterol, triglycerides, and blood sugar.” The study results suggest “the sudden death of athletes and other intensely training individuals during extreme exertion is triggered by the detrimental effects of persistent magnesium deficiency on the cardiovascular system.” (The Magnesium Miracle, Kindle page 2133)

A 2011 study in the American Journal of Clinical Nutrition found that higher plasma and dietary magnesium levels were associated with lower rates of SCD.

Potassium, too, has a protective effect against SCD, according to a 2010 review (Today’s Dietician).

Interestingly, “it’s impossible to overcome potassium deficiency without replacing magnesium” – the two are intimately related (The Magnesium Miracle, Kindle page 157). Potassium levels are often cited in discussions of arrhythmia, cardiovascular mortality and heart failure, but without enough magnesium, “the body is unable to deliver potassium to the cells” (The Magnesium Miracle, Kindle page 2463).

The importance of magnesium for the heart doesn’t stop here, though. This hard-working mineral also plays a fascinating role in managing cholesterol, arterial plaque and blood pressure.

To reduce the risk of exercise-induced sudden cardiac arrest, make sure you’re eating a heart-healthy diet, monitoring your heart health, and getting enough magnesium. 

Also, please help to spread the word. Heart attacks and strokes are the top killers in Canada. Everyone should be aware that magnesium can help.

What do studies say about magnesium for exercise?

What do studies say about magnesium and energy for athletic performance?

In a very tightly controlled, three-month study in the U.S., the effects of magnesium depletion on exercise performance in 10 women were observed.

In months 1 and 3, the women received a magnesium-deficient diet of 112 mg per day, and a magnesium supplement of 200 mg per day to reach the Recommended Dietary Allowance per day. In month 2, the supplement was withdrawn to intentionally result in a magnesium-deficient diet.

At the end of each month, the women were asked to cycle at increasing intensity until they reached 80% of their maximum heart rate, at which time they were subjected to a battery of tests.

The results clearly established that when magnesium was deficient, metabolic efficiency was reduced as both heart rate and oxygen intake increased, in essence making the body work much harder to perform the same task. (Source:  J Nutr 132:930-935, 2002)

In 2006 the same authors published an “Update on the relationship between magnesium and exercise.” Nielsen and Lukaski found that “magnesium deficiency impairs exercise performance and amplifies the negative consequences of strenuous exercise (e.g., oxidative stress) (p.180).”

The authors concluded, “Magnesium supplementation or increased dietary intake of magnesium will have beneficial effects on exercise performance in magnesium-deficient individuals (Nielsen & Lukaski, 2006, p. 180).”

In healthy elderly women, a randomized, controlled trial found that magnesium supplementation induced a significant improvement in short physical performance. The most significant outcomes were observed more notably in subjects whose diets were lower in magnesium (Veronese et al., 2014).

Other studies contrasting athletes under magnesium supplementation with control groups have found that “magnesium supplementation positively influences performance (Cinar, Nizamlioglu, Mogulkoc, & Baltaci, 2007)” and that it “improved alactic anaerobic metabolism” even in athletes who were not magnesium-deficient (Setaro et al., 2014).

In The Magnesium Miracle, Dr. Dean writes,

“Some of the first studies showing the relationship between magnesium and physical exercise were done on animals and found that decreased exercise capacity can be an early sign of magnesium deficiency.

When the animals were given magnesium dissolved in water, their endurance was restored. Most human studies also confirm that both brief and extended exercise depletes magnesium.” (p. 70)

How much magnesium do you need for fitness and exercise performance?

magnesium for energy

No two people have the same magnesium requirements. Body size, age, lifestyle, stress, and exercise levels are factors.

“Twenty years of research shows that under ideal conditions approximately 300 mg of magnesium is required merely to offset the daily losses. If you are under mild to moderate stress caused by a physical or psychological disease, physical injury, athletic exertion, or emotional upheaval, your requirements for magnesium escalate.” (The Magnesium Miracle, Kindle version page 4167)

By conservative estimates, working out increases your body’s magnesium demands by 10 – 20% (US Department of Agriculture). That means, if your RDA for magnesium is 400 mg/day before exercise, you may need closer to 500 mg if you workout.

Unfortunately, most of us aren’t meeting our magnesium requirements through diet alone. For one, most people don’t eat enough dark leafy greens, legumes, nuts, and seeds. Yet, even if you do, those foods deliver less magnesium than whole foods did 100 years ago because of the leeching of soils through industrial agriculture.

“An average good diet may supply about 120 mg of magnesium per 1,000 calories, for an estimated daily intake of about 250 mg.” (The Magnesium Miracle, Kindle version page 4167)

The best way to determine whether you are getting enough magnesium and to find your intake sweet spot is by looking at symptoms. Some of the most common symptoms of low magnesium are tension, cramps, pain (headaches and muscle pain), restlessness, anxiety, difficulty sleeping, and even constipation.

Address your low magnesium now to prevent fatigue, lethargy, weakness, nausea, and other health risks linked to magnesium deficiency.

Discovering magnesium for fitness: Dr. Tanner’s story

“It was during my endurance training for Toronto’s Scotia Bank Marathon that I discovered the potential of magnesium.

Before I started to supplement with magnesium, I would experience a three-day headache after running any distance over 10 km. Not fun.

No amount of Tylenol or Advil could alleviate this constant throb. Something had to change and quitting running didn’t seem like an option!

I picked up a bottle of magnesium and began with 1/2 tsp. I slowly increased the dose over a few weeks.

With this small change, my headaches never materialized and my energy later in the day improved. The musculoskeletal benefits also gave my knees a break and lessened post-run pain.

I knew that a deficiency in magnesium can lead to fatigue, muscle cramps/twitches, and reduced performance. The tension headaches I was feeling were being created from running posture-related stress around my neck and shoulders and my body did not have the magnesium it needed to relax the muscles.

Serotonin receptors, nitric oxide synthesis and release, and a variety of other neurotransmitters are affected by magnesium concentrations, which is why it had such profound effects on my post-run headaches.

Take it from me: Don’t ignore your symptoms, which are your body’s way of telling you something is wrong.

Thanks to this discovery, it was less painful for me to accomplish my lifelong goal of running a marathon. You can too.”

Dr. Jennifer Tanner, ND, has a broad, evidence-based practice with a focus on Sports Medicine, Pediatrics and Fertility. She is a recipient of the Dr. Shimon Levytam Award and has appeared in Today’s Parent, and Best Health. Dr. Tanner uses Acupuncture and Clinical Nutrition putting an emphasis on “food as medicine”. 

Jennifer is part of the Integrative Health Institute team with a clinic located on Sherbourne Street in Toronto, near the St. Lawrence Market.

Athletes need magnesium for fitness

Whether you’re a casual exerciser, a fitness buff, or a serious athlete who trains hard every day, make sure you’re getting enough magnesium as part of your performance nutrition and recovery plan.

Not sure if you’re getting enough?

Muscle cramping and spasms, shortness of breath, rapid pulse and even a feeling that your heart ‘skips a beat’ during workouts are all signs of magnesium deficiency.

The good news is that magnesium is easy to replenish with Bolton’s Naturals topical magnesium

This wraps up our post on magnesium for exercise. If you work out – or want to – be sure to get enough magnesium.

And please help us to get the word out by sharing this information! Most Canadian adults are deficient in magnesium, so it’s a message nearly everyone needs to hear.


  1. Carolyn Dean, MD, ND. The Magnesium Miracle (Updated and Revised)

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