Magnesium might be the most important mineral runners overlook — and the science shows its impact reaches far beyond cramps or sleep. In this episode, Coaches Chris and Maya break down how magnesium affects energy production, muscle contraction and relaxation, neuromuscular control, cardiovascular stability, and long-term training health.

Most runners focus on sodium and potassium, but magnesium is the mineral that makes those electrolytes work. It regulates ATP activation, maintains ionic gradients, supports heart rhythm, and prevents subtle but performance-killing deficiencies that standard blood tests often miss.

What you'll learn:

• Why only 1% of your body’s magnesium is detectable on standard blood tests
• How magnesium activates ATP — the fuel for every stride
• The role of magnesium in muscle contraction & relaxation
• How low magnesium leads to cramps, fasciculations, and heavy legs
• Why modern diets and high calcium intake deplete magnesium
• The link between magnesium deficiency and cardiac arrhythmias
• Why the RDA is the minimum and not optimal for runners
• How sweat rate, heat, and training load increase magnesium loss
• Evidence-based intake ranges for athletes and high-volume runners

Show Notes:

• Magnesium is the second most common intracellular cation after potassium
• Only 1% of magnesium appears in serum — making deficiency hard to detect
• Low magnesium disrupts ATP activation and ionic gradients
• Subclinical deficiency can cause cramps, twitches, anxiety, and reduced performance
• Magnesium deficiency is linked to arrhythmias and cardiovascular risk
• RDA (300–420 mg) is the minimum — athletes often require more
• High calcium & phosphorus intake increases magnesium demand
• Training in heat and heavy sweating accelerate magnesium loss

Find companion articles, training tools, and related nutrition guides at HalfMarathonTrainingPlan.com.