Electrolytes for Athletes: When You Need Them (and When You Don’t)

Harrison Armitage
Sep 15
4 min read

Electrolytes are more than just another trend in the world of health & fitness. They are full of electrically charged minerals (sodium, potassium, chloride, calcium, magnesium) which dissolve in body fluids and power your critical functions like muscle contractions, nerve impulses, and fluid balance (Keefe et al., 2024).

When you sweat, you don’t just lose water but also these essential minerals. Fail to replace them, and performance can dip hard. Your heart rate may climb faster, endurance can drops, and even mental focus take a hit (Ayotte et al., 2018).

For Amateur Athletes, understanding when you really need electrolytes can be the difference between a strong finish and a sluggish, fatigued session.

Why Electrolytes Matter for Performance

Just drinking enough water may not keep you hydrated, you need to keep the right balance of fluids and minerals. Research shows that losing even 1-2% of your body weight through sweat can impair aerobic capacity, slow reaction time, and make exercise feel much harder (Ayotte et al., 2018).

Electrolytes, particularly sodium, help your body retain or ‘hold on’ to the fluid you drink. In fact, rehydration drinks that include sodium lead to better fluid retention and faster recovery compared to plain water (Ly et al., 2023). This means steadier energy levels, better muscle function, and a lower risk of cramps when the heat or the training load increases (Choi et al., 2021).

Who Actually Needs Electrolyte Supplements?

Not everyone needs to reach for an electrolyte tablet or sportys drink after every workout. The need depends on sweat rate, session duration, and climate.

If you’re training or competing for more than 90 minutes, particularly in heat or humidity, you’ll likely benefit from electrolyte replacement.
Double training days or heavy back-to-back sessions are another case where topping up helps restore balance before the next workout (Shirreffs, 2011).
People who naturally sweat heavily, even in cooler conditions, often report fewer cramps and better energy when they replenish sodium and potassium.

But the key caveat is that sodium isn’t always low in modern diets.

The Sodium Problem: UPFs and Over-Supplementation

A narrative we here all too often, and rightly so, is that many of us consume too much ultra-processed foods (UPFs) like packaged snacks, sauces, and ready meals. Studies show UPFs contribute the majority of daily sodium intake in Western diets (Zhang et al., 2025). If you’re eating a lot of these foods and then adding electrolyte drinks daily, you could tip into excessive sodium intake, linked to high blood pressure and increased cardiovascular risk.

This doesn’t mean you should avoid electrolytes altogether, but it’s a reminder to be intentional. Check your food labels, know your sweat rate, and use electrolyte supplements where they add value, not out of habit.

Nutritionist Rob Hobson describes this well here - https://www.instagram.com/reel/DNAJWupI7gi/

Timing Electrolytes Around Training

Before training: Aim to start well-hydrated. If yesterday’s session was sweaty or you’ve had a low-fluid day, drink water with a pinch of sodium or a low-dose electrolyte tab. This helps start the session in a state of “euhydration”, your ideal total body water content (Shirreffs, 2011).

During training: For long or hot sessions, sip an electrolyte drink steadily instead of downing plain water all at once. This helps keep blood sodium stable and maintains muscle function (Choi et al., 2021).

After training: Pairing fluids with electrolytes and a small amount of carbohydrate leads to better fluid retention, faster plasma volume recovery, and improved readiness for your next session (Ly et al., 2023).

Practical Takeaway for Amateur Athletes

Electrolytes are not just for pros like marathon runners, they matter for anyone training consistently, especially in warm environments. But this doesnt mean you should be consuming sports drinks every day. The smart play is to tailor intake to your training load, sweat rate, and diet.

If you eat a diet rich in whole foods and low in UPFs, electrolyte supplements may fill a gap. But if your diet already supplies plenty of sodium, you could instead focus on water and potassium-rich foods such bananas, potatoes, and leafy greens. The goal isn’t just to rehydrate, it is to restore the right balance of minerals.

Key Points

Electrolytes keep your body in balance - crucial for muscle contractions, nerve signaling, and hydration.
Performance drops quickly with dehydration - even mild fluid loss raises heart rate and reduces endurance.
Supplement smartly: Use electrolytes for long sessions, heavy sweating, or hot conditions - but don’t ignore dietary sodium from UPFs.
Hydration = water + electrolytes: Together, they support fluid retention, recovery, and next-day performance.

References

Keefe, M. S., Benjamin, C. L., Casa, D. J., & Sekiguchi, Y. (2024). Importance of Electrolytes in Exercise Performance and Assessment Methodology After Heat Training: A Narrative Review. Applied Sciences, 14(22), 10103. https://doi.org/10.3390/app142210103
Shirreffs, S. M. (2011). Fluids and electrolyte needs for training, competition, and recovery. Journal of Sports Sciences, 29(suppl S1), S39-46. https://pubmed.ncbi.nlm.nih.gov/22150427
Ly, N. Q., et al. (2023). Post-Exercise Rehydration in Athletes: Effects of Sodium and Carbohydrate. Nutrients, 15(22), 4759. https://doi.org/10.3390/nu15224759
Choi, D. H., et al. (2021). Effects of Electrolyte Drink vs Water on Exercise Capacity and Recovery. Applied Sciences, 11(19), 9093. https://doi.org/10.3390/app11199093
Ayotte, D., et al. (2018). Individualized hydration plans: impact on performance. Journal of the International Society of Sports Nutrition, 15, 60. https://doi.org/10.1186/s12970-018-0230-2
Zhang, Y., et al. (2025). Association Between Increased Dietary Sodium Intake and Physiological Responses. PMC article. https://pmc.ncbi.nlm.nih.gov/articles/PMC11990302