Do I need electrolytes after a workout?

Usually not. For sessions under about 60–90 minutes in normal conditions, water plus your next meal replaces what you lost. Electrolyte replacement matters for prolonged endurance work, heavy sweating in heat, or if you are a salty sweater, visible white residue on skin or clothing.

How much sodium do you lose in sweat?

Roughly 500 to 1,500 mg per liter of sweat, varying several-fold between individuals. Sweat rates in hard exercise run about 0.5–2 liters per hour, so a long hot session can cost well over 1,000 mg of sodium.

Are electrolyte powders worth it?

For the right situation, yes, and they are mostly salt. A typical packet is sodium, some potassium and magnesium, and flavoring. If you are eating normal meals with any salt in them, most of that is already covered outside of endurance contexts.

Electrolytes: who actually needs them

The powders are marketed to everyone and useful to a much smaller group. Here is the line: sweat rate, duration, and heat, not whether you went to the gym.

The AIM teamOctober 8, 20264 min read

Electrolyte powders went from a cycling-team product to a lifestyle one in about five years. The marketing implies a deficit most people do not have.

Here is the line worth drawing.

What you actually lose

Sweat is mostly water, but it carries sodium, roughly 500 to 1,500 mg per liter: with genuinely large individual variation. It also carries small amounts of potassium, magnesium and calcium, in quantities that normal food replaces without effort.

So the question is not "did I sweat" but "how much, for how long, and how salty is mine".

When supplementation is justified

Three conditions, and you generally want at least one:

Duration beyond 60–90 minutes of continuous hard effort. Below that, glycogen and water are the limits, not sodium.
Heat. Sweat rates climb steeply, and the same session in 90°F costs far more than in 60°F.
You are a salty sweater. The test is visible: white residue on your skin, gritty taste, salt rings on a dark shirt after drying.

Endurance events, outdoor labor, hot yoga, long hikes. Not a 45-minute lifting session in an air-conditioned gym.

The risk of over-drinking plain water

Worth knowing because it runs opposite to the usual advice. In very long events, drinking large volumes of plain water while losing sodium in sweat can dilute blood sodium, exercise-associated hyponatremia. It is rare, it is dangerous, and it happens to careful people who were told to stay hydrated and did so enthusiastically.

That is the actual case for electrolytes in endurance sport: not performance, but not diluting yourself over five hours.

What is in the packet

Mostly salt. A typical serving is 300–1,000 mg sodium, 100–200 mg potassium, some magnesium, and flavoring.

Which means for most purposes the cheap version works: water, a pinch of salt, and something with potassium. The commercial products are convenience and taste, which are real but are not physiology.

If you track it

Electrolyte drinks land in your sodium number, and for anyone capping sodium that matters, a packet can be a third of a daily limit. Worth logging as a drink rather than treating as free.

Common questions

Do I need electrolytes after a workout?: Usually not. For sessions under about 60–90 minutes in normal conditions, water plus your next meal replaces what you lost. Electrolyte replacement matters for prolonged endurance work, heavy sweating in heat, or if you are a salty sweater, visible white residue on skin or clothing.
How much sodium do you lose in sweat?: Roughly 500 to 1,500 mg per liter of sweat, varying several-fold between individuals. Sweat rates in hard exercise run about 0.5–2 liters per hour, so a long hot session can cost well over 1,000 mg of sodium.
Are electrolyte powders worth it?: For the right situation, yes, and they are mostly salt. A typical packet is sodium, some potassium and magnesium, and flavoring. If you are eating normal meals with any salt in them, most of that is already covered outside of endurance contexts.