What are electrolytes and how do they affect hydration?

When you think about hydration, water likely comes to mind first. But staying hydrated means more than just drinking fluids. Your body also needs electrolytes, which are minerals that carry an electric charge and help move fluid in and out of your cells. Without the right levels of electrolytes, drinking water alone may not adequately hydrate your body.

“Our bodies rely on electrolytes to function properly, especially when it comes to hydration,” says Jeevan Chechakunnil Abraham, MD, a sports medicine physician at Northwestern Medicine.

The most common electrolytes include:

• Sodium
• Potassium
• Magnesium
• Chloride
• Bicarbonate
• Phosphate

In addition to maintaining your fluid balance, electrolytes help regulate:

• Muscle and nerve function, including the heart
• Blood pressure
• pH levels in your blood
• Cellular processes

“Your body is built to maintain a certain level of electrolytes at all times,” says Perry Xu, MD, a urologist at Northwestern Medicine. “Without them, your organs, muscles and nerves can’t function properly.”

How do you know if you are low on electrolytes?

Symptoms vary depending on which electrolyte is low, but common signs are:

• Muscle cramps or twitching
• Fatigue or weakness
• Dizziness or confusion
• Nausea or vomiting
• Dry mouth
• Irregular heartbeat

If any of these symptoms persist, see a physician. A blood test can help determine if you have an imbalance.

Can you have too many electrolytes?

Yes. Over-supplementing can lead to:

• High sodium: increased blood pressure
• High potassium (hyperkalemia): dangerous heart rhythms
• High calcium or magnesium: kidney problems, nausea, confusion

Symptoms of excess electrolytes often mimic deficiency — confusion, muscle cramps and fatigue — because your body needs balance.

Can you get enough electrolytes from food?

Yes. Most people can meet their electrolyte needs through a balanced diet. Foods high in electrolytes include:

• Sodium: table salt, pickles, soups
• Potassium: bananas, potatoes, spinach, avocados
• Calcium: dairy, leafy greens, tofu
• Magnesium: nuts, seeds, whole grains, legumes

“Fruits and vegetables are naturally high in electrolytes,” says Dr. Xu. “Supplements may be needed only if you have a medical condition or are on certain medications.”

Do you ever need electrolyte drinks?

They are not necessary for everyone but may be helpful if you:

• Exercise intensely for over an hour
• Sweat heavily or have salty sweat
• Are ill with vomiting or diarrhea
• Are exposed to high heat for long periods
• Are recovering from a hangover

“For most people, water and a well-balanced diet are enough,” says Dr. Abraham.

When should you take electrolytes for a workout?

Dr. Abraham offers these guidelines on electrolyte drinks before, during and after a workout:

Before: Only necessary if you're exercising in extreme heat or doing long or intense workouts. In the days before an endurance event, increasing dietary sodium can prevent you from starting a race with low blood sodium concentration. This will make you less likely to develop hyponatremia (too little sodium in your blood) during or after a race.

During: Useful for long workouts, such as training for a marathon, especially if you have significant salty sweat. Sodium, in particular, can stimulate thirst to help you replenish and retain fluids.

After: Important for recovery, especially if you’ve lost a lot of sweat during a workout.

Natural options like coconut water can help, but they may not contain enough sodium to replace the salt lost through heavy sweating.

Electrolytes and Kidney Health

“Think of your kidneys as your body’s water filtration plant,” says Dr. Xu. “They need the right electrolyte levels to do their job.”

Your kidneys use electrolytes to filter blood and produce urine. Imbalances can affect kidney function and increase the risk of kidney stones.

• High sodium intake can cause calcium to be excreted in your urine, leading to stone formation.
• Contrary to popular belief, avoiding calcium is not recommended. It can actually increase stone risk.

“If you eat too much sodium, one of the only ways your kidney knows to get rid of the excess sodium in your urine is to pull calcium into your urine, which is one of the main components of most kidney stones,” says Dr. Xu. “I tell my patients to really make sure they watch their sodium intake. It can sneak its way into a lot of processed foods.” 

Electrolytes and Blood Pressure

Sodium and potassium help regulate fluid levels and blood pressure. Potassium, which is considered a balancing mineral, helps relax your blood vessel walls and reduce the effects of sodium in the body. Too much sodium or not enough potassium can cause fluid retention and raise your blood pressure.

“If you have high blood pressure, we generally recommend a low-sodium diet and close monitoring,” says Dr. Xu.

What’s the best way to replenish electrolytes?

• Eat balanced meals.
• Eat salty snacks (in moderation).
• Drink fluids with added electrolytes, such as sports drinks or water mixed with electrolyte tablets or powders.
• Use natural options like coconut water for mild dehydration.

Your body may be better at absorbing electrolytes from natural sources than from supplements. Getting electrolytes from your diet also helps lower your risk of consuming too much. However, depending on your situation and access, any electrolyte source may be beneficial if you are depleted. 

“The key is balance,” says Dr. Xu. “Your body functions best when electrolytes are within the right range.”