Electrolytes & Hydration: When Water Isn’t Enough (and What You Should Do)

You know the feeling: You sweat heavily, drink water—and still crash after 60–90 minutes. Headaches, heavy legs, sometimes even cramps. Often, the problem isn’t “too little water,” but too little salt.

In this guide, you’ll get a clear answer to two questions: How much should you drink during exercise? And when is water no longer enough? Explained clearly—with rules of thumb you can apply directly in your next session, whether you run, cycle, or sweat it out in the gym.

Replenishing is only the beginning—the question is what it needs to contain.

What electrolytes are and why sweat is the game changer

Electrolytes are charged minerals that help regulate fluid balance, nerve conduction, and muscle contractions in your body. In sports, sodium (salt), potassium, calcium, and magnesium are particularly relevant. The key point: You lose water and sodium through sweat. If you then drink only water, your blood sodium concentration can drop—and that can intensify symptoms such as headaches, nausea, or a drop in performance.

During very long efforts, drinking too much can even increase the risk of so-called exercise-associated hyponatremia—a condition in which your sodium levels drop dangerously low. It doesn’t only happen to ultrarunners: Ambitious recreational athletes can also be affected.

Four signs you are more likely lacking salt than water

When your body needs electrolytes, it usually sends clear signals. These are the four you should know:

• Headaches after training: It could be dehydration. But if you have drunk enough and it still happens, sodium is often the missing piece—especially in the heat or during long sessions.
• Cramps late in a session: Cramps are rarely “just magnesium.” They are often a mix of fatigue, high exertion, and an unfavorable fluid/electrolyte shift.
• Dizziness and shaky legs: If you feel as though someone has pulled the plug, it may be due to excessive losses or an unsuitable hydration strategy. Sodium helps your body retain fluids more effectively.
• Salt marks on your skin or clothing: White traces are a pretty direct sign: You are visibly losing salt. That does not automatically mean “you need an extreme amount,” but water alone is definitely not enough.

Recovery starts with proper hydration—before, during, and after your session.

How much to drink—without overdoing it

There is no perfect number for everyone. But there are clear guidelines: During intense endurance exercise, a range of 0.4–0.8 liters per hour is often cited, depending on temperature, intensity, and sweat rate. This is clearly stated in the ACSM Position Stand on Hydration in Sport.

Important: If you weigh more at the end of a long session than you did beforehand, you very likely drank too much fluid. The fastest way to find your individual fluid intake is the sweat test: weigh yourself before the session, record how much you drink, then weigh yourself afterward. Weight loss plus fluid intake equals your sweat loss. For sodium, a target of 500–700 mg per liter of drink is a good guideline—this is also supported by the ISSN Position Stand on Hydration and Electrolytes.

DIY or electrolyte drink—which makes sense?

You don’t need a fancy product. What matters is getting sodium in a form that works for you during training. A simple DIY option: water plus a small pinch of salt plus a little juice for flavor. One teaspoon of salt contains around 2,400 mg of sodium. This lets you work out the amounts logically without overdoing it. Ready-made electrolyte drinks are convenient, but not essential.

Important: If you have high blood pressure, kidney or heart issues, or take medication, discuss salt strategies with a medical professional first.

Athlix recommendation – Hydrate smart

If you don’t want to stand around in a soaking-wet shirt after a hard session, dry change clothes are a real recovery hack. A fresh Athlix T-shirt and, later, a warm Athlix hoodie keep you warm after long sessions—especially when your fluid balance hasn’t fully recovered and your body cools down faster.

Conclusion

Water is the foundation. But as sweat and duration increase, sodium becomes a performance factor. When you know when you need electrolytes and how to keep it simple, you train more consistently, recover better, and have fewer “random” issues like headaches or cramps. Take the sweat test, determine your needs, and intentionally add sodium to your next long sessions.

Give it a try and tag us on Instagram at @athlix.performance – we look forward to seeing how you optimize your hydration and sharing the best posts with the community.