You know the feeling… You’re cruising along your favorite route, your cadence smooth, your watts in their sweet spot- and the pain hits out. Your legs seize up, muscles knotting like a death grip. Sharp pain shoots through your quads and hamstrings, threatening to turn a great ride into a limp back home.
Before I started cycling, I thought a basic multivitamin was all I needed for nutrition. But once I got into a training program, I discovered that electrolyte supplements for endurance athletes could make a difference in performance and in how I felt. One of the most surprising and effective supplements is magnesium, a mineral that quietly powers muscle function, energy production, and recovery.
If you’re struggling with cramps, poor recovery, or low energy, this article is for you.
What Is Magnesium and Why Cyclists Need It
Magnesium is sometimes called the forgotten electrolyte, but it actually has a pretty big impact. It is one of the most essential electrolytes, along with sodium, potassium, calcium, and chloride.
Electrolytes are charged particles (ions). These tiny particles actually help your body conduct electricity – that’s what enables muscle contractions when you pedal and works to maintain hydration and fluid balance.
Magnesium plays a crucial role in nerve and muscle function, as well as electrolyte balance. It supports more than 300 biochemical reactions in the body, supports a healthy immune system, strong bones, and a steady heartbeat. Magnesium helps adjust blood glucose levels and aids in the production of energy and protein.
Why Magnesium Matters for Endurance Athletes
Although magnesium seems like such a tiny element, it’s surprisingly important in the work of being an endurance athlete. Here’s what it does:
Energy Production. Going the distance? You need magnesium. Magnesium plays a part in the creation of ATP – that’s cellular energy. Without magnesium, it will be hard for your muscles to convert food into fuel, which means you end up with fatigue and decreased performance.
Hydration and Electrolyte Balance. Magnesium, alongside other key electrolytes, helps to regulate your hydration and muscle contraction. You lose magnesium when you sweat. If your levels drop too low, you might suffer from muscle cramps, spasms, weakness, and dehydration.
Muscle Function and Recovery. Magnesium helps your muscles contract and relax with every pedal stroke or stride. It’s also essential for protein synthesis, which helps to build and repair muscles.
Inflammation Control. Your body responds to training stress with inflammation, which requires recovery. Magnesium has anti-inflammatory properties, which help you recover better.
Heart Health. Your heart is your most important muscle if you’re an endurance athlete or cyclist. Magnesium is essential for cardiovascular health and regulates heart rhythm, blood flow, and circulation, and supports healthy blood pressure. If your magnesium is too low, you may. Have irregular heartbeats, high blood pressure, and lower endurance.
Stress management. Magnesium has a calming effect by regulating stress hormones and supporting the nervous system. It promotes better sleep, which is essential for recovery. It can improve focus and reduce anxiety and stress during training and racing. This calming effect may even alleviate gastrointestinal distress.
Common Signs of Magnesium Deficiency in Cyclists
- Cramping
- Fatigue
- Poor Recovery
- Sleep disruptions
- Mental fog
One big contributor to magnesium deficiency is sweat loss. Sweat loss can be attributed to a 12% reduction in the body’s magnesium stores, and it only takes a small magnesium deficit to create symptoms.
How Indoor Cyclists Lose Magnesium Faster
As we’ve seen, sweat loss causes cyclists to lose magnesium. The higher the sweat loss, the greater the magnesium depletion. Cycling in indoor training environments almost always creates a higher sweat rate. Even with fans, there is a lack of airflow indoors that reduces the heat transfer from your body to the surrounding air (you stay hotter). The air inside is more humid, which means your sweat doesn’t evaporate as well, leaving you hotter and causing you to sweat even more.
Often, intense sessions are done on a trainer to dial in better. These fierce sessions usually generate more sweat! Without proper hydration, you’re at a greater risk of dehydration and electrolyte deficit, such as magnesium. That’s why your indoor cycling nutrition might need to be adjusted compared to your outdoor cycling. You sweat more, so you need to replenish your electrolytes more.
Magnesium Versus Other Electrolytes: What Sets It Apart
Dr. Colleen Gulick, in her article “Electrolytes: The Unsung Heroes of Hydration and Performance,” offers a run-down of some of the best electrolytes for cycling:
“Sodium (Na+): Regulates fluid balance, nerve transmission, and muscle contractions.
Potassium (K+): Essential for nerve and muscle cell function, including the heart.
Calcium (Ca2+): Crucial for muscle function, blood clotting, and bone health.
Magnesium (Mg2+): Supports muscle and nerve function, bone health, and energy production.
Chloride (Cl-): Helps regulate fluid balance and is essential for digestion.
Phosphate (PO4^3-): Involved in energy production and bone health.”
Magnesium plays a key role in electrolyte balance. It is unique among the other electrolytes because it is involved in over 300 enzymatic reactions. However, it’s been nicknamed the “forgotten electrolyte” because deficiencies can appear subtle despite the critical role it plays in the body.
You won’t find magnesium in most common electrolyte drinks. They focus on restoring sodium and potassium, which are lost in greater amounts in sweat than magnesium is. Also, high doses of magnesium can cause stomach upset, which we obviously want to avoid during training and racing. The amount of magnesium needed really varies from athlete to athlete.
After looking at the correlations between magnesium and muscle cramps, perhaps it should be added to your favorite sports drink. It clearly plays a large part in muscle and nerve function, restoring electrolyte balance and energy production. If you know how much magnesium you personally need, you can add it to your favorite sports drinks.
Top Magnesium-Rich Food for Cyclists
If you eat a well-balanced, nutrient-dense diet, you may be able to get enough magnesium from your diet. Consider incorporating these foods if your diet allows:
- Dark chocolate: 65mg in a one-ounce serving
- Avocado: 58mg each
- Nuts, especially almonds, cashews, and Brazil nuts
- Tofu: 35mg per 3.5 ounces
- Seeds such as flax, pumpkin, and chia
- Whole grains such as wheat, oats, barley, quinoa, and buckwheat
- Leafy greens like kale, spinach, collard greens, turnip greens, and mustard greens
While many people can get enough magnesium from their diet, some people cannot. Older adults, people with certain health conditions, and athletes who are heavy sweaters may need supplementation. If you experience cramping, fatigue, and brain fog, among the other symptoms we already discussed, you may need to talk to your doctor about a magnesium supplement.
Should Cyclists Supplement Magnesium?
Laura Kunces, Vice President of Medical Strategy for Thornes, says, “You lose a lot of magnesium through the contraction and relaxation processes of moving your muscles, so athletes usually need about 20 percent or more than the average person.” If you are very active, are participating in an intense racing season, or working through a hard training block, you may want to consider adding a magnesium supplement. But which type? According to Healthline, there are 10 different types of magnesium supplements, each with somewhat different benefits and side effects.
