Electrolyte Insights

Do You Need Electrolytes for a One-Hour Gym Session?

October 18, 2026

Science with Zac - Zac

Science with Zac, Edition 01: Electrolytes for one hour?

Science with Zac ● by Zac

The 30-second version

Your sodium is a bank account. Food is the deposit, sweat is the withdrawal.
Withdrawal size = how much you sweat × how salty your sweat is.
Both swing wildly between people, so there is no one rule. A bathroom scale gets you halfway to your number.

Your sodium is a bank account

A workout is one withdrawal in your day. A $5 coffee does not wreck your account. A $500 car repair might.

So the real question is not “do I need electrolytes?” It is “how big was the withdrawal?”

Faucet or fire hose? Light broth or ramen?

Two things set the size of the withdrawal. First, how much you sweat. Some people sweat like a dripping faucet, others like a fire hose:

A dripping faucet fills a jug to 0.26 liters in an hour while a fire hose fills another to 5.73 liters — Animated. Lowest vs highest sweat rate in 506 athletes (Baker et al., 2016).

Second, how salty that sweat is. Some sweat is a light broth. Some is a salty ramen broth:

Two bowls with the same liter of sweat: the light broth gets 4 salt grains, the ramen broth gets 16 — Animated. Lowest vs highest sweat sodium in 506 athletes (Baker et al., 2016). 1 grain = about 100 mg.

Here are both ranges side by side, with the averages marked:

Same hour, very different sweat

How much 506 athletes sweated, and how salty that sweat was

Sweat per hour (scale 0 to 6 L)

Lowest
0.26 LAverage
1.21 LHighest
5.73 L

Sodium in each liter of sweat (scale 0 to 1,800 mg)

Lowest
420 mgAverage
826 mgHighest
1,630 mg

Baker et al., 2016, J Sports Sci. Whole-body sweat sodium was predicted from forearm patches. We converted mmol to mg at 23 mg per mmol.

Same gym, same hour, different bill

The math: sweat × saltiness = sodium lost. Example numbers to show how it plays out:

Person A: 45-minute lift, air-conditioned gym, shirt barely damp. 0.5 L × 826 mg ≈ 400 mg.
Person B: an hour of sleds and rowing, garage gym in August, shirt soaked. 2 L × 1,200 mg ≈ 2,400 mg.

Two sodium accounts: Person A spends 2 sodium cubes, Person B spends 12, then food refills both — Animated. Example numbers, not measurements. 1 cube = 200 mg of sodium.

Same hour on the clock, six times the withdrawal. Your sport moves the average too. Football players lost about twice as much sodium an hour as baseball players:

Sodium lost per hour, by sport

Average sweat sodium loss in 1,303 athletes

American football

1,286 mg

Endurance

1,189 mg

Soccer

796 mg

Basketball

794 mg

Baseball

626 mg

Barnes et al., 2019, J Sports Sci. Averages only: in football alone the spread was 55.9 ± 36.8 mmol an hour. We converted mmol to mg at 23 mg per mmol.

But look at the note under that chart. The spread inside each sport is huge, so your sport’s average is not your number.

Find your number with a bathroom scale

Same idea as checking how much gas a road trip used: read the gauge before and after. Athletic trainers recommend measuring your own sweat rate this way (McDermott et al., 2017):

Pee, then weigh yourself in minimal clothing.
Train one hour. Write down what you drink.
Towel off and weigh again in the same clothing.
Sweat lost ≈ weight lost + what you drank. One pound is about 16 oz.

Think of 2% of your body weight as your fuel light. The American College of Sports Medicine says to avoid losing more than that to sweat during exercise (Sawka et al., 2007). For a 180-pound person, that is 3.6 pounds.

Don’t just add water

Pour water into salty soup and it does not get better. It gets watery:

Water pours into a bowl of salty soup; the same salt spreads out and the salt-per-sip meter drops — Animated. Same salt, more water. Your blood works the same way (Hew-Butler et al., 2015).

The main cause of dangerously low blood sodium during exercise is drinking more than your thirst asks for (Hew-Butler et al., 2015). Drink to thirst.

The 3-question check

Before your next session, ask:

How long? Under an hour or well over?
How hot? Air-conditioned gym or summer garage?
How soaked? Damp shirt or wring-it-out shirt?

Short, cool and damp: small withdrawal. Long, hot and soaked: worth knowing your numbers.

Where a pouch fits

One +Pouch has 300 mg of electrolytes, including 105 mg of sodium. It is a small deposit you can make between sets, with no shaker bottle. It is not built to cover Person B’s whole withdrawal on its own.

Know your withdrawal first. Then decide your deposit.

Zac, +Pouch

Sources

Baker LB, et al. Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes. J Sports Sci. 2016;34(4):358-368. PubMed 26070030
Barnes KA, et al. Normative data for sweating rate, sweat sodium concentration, and sweat sodium loss in athletes: an update and analysis by sport. J Sports Sci. 2019;37(20):2356-2366. PubMed 31230518
McDermott BP, et al. National Athletic Trainers’ Association position statement: fluid replacement for the physically active. J Athl Train. 2017;52(9):877-895. PubMed 28985128
Sawka MN, et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377-390. PubMed 17277604
Hew-Butler T, et al. Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clin J Sport Med. 2015;25(4):303-320. PubMed 26102445

This post is for education and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Want the details? Read how an electrolyte pouch works, or see +Pouch electrolyte pouches.