Quick answer

Take electrolytes around the sweat they replace. For a long or hot session, that means sodium during exercise, about 300 to 600 mg an hour, and fluid with sodium afterwards. Any extra drinking beforehand should start several hours ahead. For an hour or less of exercise, a normal meal and water usually cover it.^1,2,3

Key facts

NIH points to endurance exercise lasting more than an hour, or done in heat or at altitude, as the point where fluid and electrolyte replacement may be needed.³
The ACSM position stand says extra drinking before exercise should begin at least several hours ahead.²
After sweating, drinking 1.5 times the weight lost, with sodium, kept more fluid in the body over 6 hours in a lab study.⁴
A modelling study found sodium replacement unnecessary in every realistic soccer or elite marathon scenario it tested.⁵

Before exercise

Position stands advise starting exercise well hydrated. When extra drinking is needed, it should begin at least several hours before, so the body can absorb the fluid and urine output can settle back to normal.²

For most sessions, arriving after a normal meal and some water is the whole plan. Drinking a large amount right before you start mostly fills your bladder, because the kidneys need time to settle. A drink with sodium a few hours ahead is mainly worth it before a long event in the heat.^1,2

During exercise

During exercise, drinks with electrolytes and carbohydrate can do better than water alone in some situations. Because sweat rates and sweat sodium vary so much, the advice is a plan matched to your own losses rather than a set amount.^2,6

Past about 2 hours, or in heat, most guidance for sodium is 300 to 600 mg an hour, taken in drinks or salty snacks along the way.¹

For an hour or so of lifting or a short run, nothing needs to be taken during the session. A modelling study found that sodium replacement was not needed in any realistic soccer or elite marathon scenario, so in shorter efforts it comes down to taste.⁵

In long events, avoid drinking far beyond thirst. Overdrinking is the most common cause of low blood sodium in endurance sport, and an electrolyte drink does not make it harmless.^7,8

After exercise

After exercise the goal is to replace the fluid and sodium lost. In a lab study, people who drank 1.5 times the weight they had lost in sweat passed less urine over the next 6 hours the more sodium the drink contained.^2,4

Recovery is where timing matters most if you train again the same day. Drinking more than you sweated, with sodium from a drink or from food, restores fluid balance more fully than plain water. If your next session is tomorrow, normal meals with water can replace what you lost.^2,4,9

Morning or night?

No study we found compares taking electrolytes in the morning with taking them at night. What matters is when you sweat, not the clock.

The hourly sodium figure is tied to how long you exercise, the heat and how much you sweat, not to a time of day, so the same logic applies to a morning run and an evening one.¹

What's in ours

What’s in ours

Creatine + Electrolytes: Sodium, 1,000 mg per serving, from the label

The label on Creatine + Electrolytes directs one scoop a day in 6 to 8 oz of water. With 1,000 mg of sodium a scoop, a long or sweaty training day is the natural time to use it, and plenty of water alongside makes it easier to drink.^1,10

Timing around medicines

Timing matters most around some antibiotics. Magnesium, found in many mixes, can keep tetracycline and quinolone antibiotics from being absorbed, and their labels give spacing rules. Ask your pharmacist how those rules apply to your drink.^11,12

Lithium is the other case. Its label says not to change the amount of salt in your diet, so a new high-sodium drink at any time of day is a question for your prescriber.¹³

Questions people ask

Should I take electrolytes before or after a workout?

For most workouts, after, in the form of a normal meal and water. Before matters when you start short of fluid or face a long, hot session, and during matters for sessions past about 2 hours.^1,2,9

When should I take electrolytes before a run?

For a run under an hour there is no need. For a long run in the heat, start well hydrated, with any extra drinking a few hours before, and plan sodium during the run if it lasts more than about 2 hours.^1,2,3

See what we make

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See the Full Measure line Creatine + Electrolytes

Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.