Outcome
    Limited
    Effectiveness 3/5

    Magnesium for Heart Rate Variability

    Magnesium supports autonomic balance and sleep quality, both of which raise HRV, though trials measuring HRV directly are few.

    Overview

    Magnesium supports autonomic balance and sleep quality, both of which raise HRV, though trials measuring HRV directly are few.

    Verdict

    Mixed evidence

    Plausible via sleep and autonomic tone, thinly studied directly.

    How It Works

    Magnesium antagonises NMDA receptors and modulates calcium handling in cardiac and neural tissue, dampening sympathetic excitability and supporting parasympathetic recovery during sleep.

    Dosing & Protocol

    Typical dose

    Recommended dose
    200-400 mg/day elemental magnesium; HRV effects have been inconsistent across small trials
    Expected timeframe
    4-8 weeks

    Protocol

    dose
    200-400 mg elemental
    form
    Glycinate
    timing
    1-2 hours before bed
    duration
    8 weeks

    Evidence

    What the studies say

    Small studies report improved HRV indices with magnesium in athletes and people with low magnesium status. The larger and better-replicated finding is improved sleep quality, which itself is a dominant HRV driver.

    Magnesium supplementation and cardiac autonomic function: a randomized controlled trial

    Score: 6/10
    2018
    rct

    Wannamethee SG, Papacosta O, Lennon L +1 more

    Higher magnesium status was associated with greater vagally mediated heart rate variability

    View source

    Effect of magnesium sulphate on fetal heart rate parameters: a systematic review

    Score: 5/10
    2014
    systematic_review
    n=932

    Nensi A, De Silva DA, von Dadelszen P +4 more

    To examine the potential effects of intravenous magnesium sulphate (MgSO4) administration on antepartum and intrapartum fetal heart rate (FHR) parameters

    View source

    Safety

    Caveats

    Effects are likely largest in those with inadequate intake. High doses cause loose stools.

    Less likely to help if

    Magnesium-replete people, and anyone whose HRV is limited by sleep, alcohol or training load.

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.