Section B · The Road & The Trail
Running
Runners sweat out sodium every mile, then put back plain water.
Thirty minutes to two hours of steady sweat, mostly outdoors, often in heat. Plain water at every fountain thins out the sodium that is left. Mile eight is where the bill comes due.
Water at every fountain is not hydration. It is dilution. Put the sodium in with it. One before. One per hour on the run. One after on long or hot days. One stick in 16 oz covers a window; the schedule below covers the day.
A salty sweater’s half: the book’s 1,000 mg of sodium an hour, over two hours, against 600 mg a stick. The bars are plain math on the book’s numbers, so they show the shape of the run. Water alone ends the run 2,000 mg short, and miles nine to thirteen run on the deepest part of that hole. A typical sweater loses about half as much and finishes ahead on the same three sticks.
The starter kit has 40 sticks in five flavors. That is one stick for every short run, or about 13 long ones.
The numbers behind running
Thirty minutes to two hours of steady sweat, mostly outdoors, often in heat. Plain water at every fountain thins out the sodium that is left. Mile eight is where the bill comes due.
Why this happens
Sweat is more than water. Every ounce takes sodium with it, and sodium helps your blood hold its volume. Lose enough, and there is less blood to carry oxygen to your muscles. Your heart rate climbs at the same pace. You run hotter. The signal that tells a muscle to relax gets noisy. The cramp, the dizzy feeling when you stand up, and the pace you cannot hold all come from that one cause.
Plain water puts the fluid back, but not the sodium. That is why water alone can feel like it is not working. The fix is to put back what left: water and the minerals that went with it, in about the same mix you lost.
A 5K ends before the loss adds up. A half takes most people about two hours, often on a warm morning, and sweat runs from the first mile. The usual habit is coffee before, then plain water at every fountain. That water puts fluid back and no sodium, so each stop thins out what is left. Nothing feels wrong through mile six. Then the heart rate drifts up at the same pace, the calves tighten, and around mile nine the walk starts. Here is why plain water does not stop the cramp, and the timing guide covers the rest of your day.
Water at every fountain is not hydration. It is dilution. Put the sodium in with it.
Forty to eighty ounces out, and the 2% line lands near mile eight
A warm run takes 20 to 40 oz of sweat an hour. Most people run a half in about two hours. For a 160-lb runner, the 2% line sits at 51 oz. A heavy sweater crosses it at about 77 minutes, close to mile eight. That is where the book puts the cramp. The cards below show it 20 minutes at a time.
The book’s 20 to 40 oz an hour, over a two-hour half. A heavy sweater crosses 2% (51 oz for a 160-lb runner) around mile eight. The book puts the calf cramp at miles eight to ten. A typical sweater finishes just short of the line. A 5K ends inside the first two cards.
One stick in the hour before, one in the flask, and one at the refill is 1,800 mg. That covers most of a two-hour half. A salty sweater on a hot day can run past it, which is why the book adds a stick after long or hot runs.
What you get back when the sodium goes in with the water
Eight men raced while about 2% down on body weight. Their 10K took 2.6 minutes longer and their 5K took 1.3 minutes longer.
Armstrong et al., Med Sci Sports Exerc, 1985Pooled across 28 studies, being dehydrated cost 8.3% of muscle endurance. Miles nine to thirteen are endurance work on tired legs.
Savoie et al., Sports Medicine, 2015At about 1.6% of body mass down, men in a controlled trial made more errors on attention tasks and felt more tired. Pacing calls late in the run get made in that state.
Ganio et al., British Journal of Nutrition, 2011Drinking more than you lost only rehydrates you when the drink carries enough sodium. Below that, the extra leaves as urine.
Shirreffs et al., Med Sci Sports Exerc, 1996At the 2002 Boston Marathon, 13% of runners tested at the finish had low blood sodium. The biggest risk was gaining weight during the race, which means drinking more than you sweat. What they drank did not change the odds. So drink to replace what you lose, not as much as you can, and weigh yourself before and after a long run.
Almond et al., New England Journal of Medicine, 2005
Dry, then hydrated, piece by piece
The red panel is what is happening now. The green one is what the next section buys you, and roughly how long each part takes to show up.
- Coffee and no water: you leave the house behind
- Sweat starts in the first mile
- Feels fine, so the fountain gets skipped
- Heart rate drifts up at the same pace
- Plain water sloshes; sodium keeps dropping
- Focus narrows; form gets sloppy
- Calves cramp and force a walk
- Headache 30–60 minutes after, and it lingers
- Wrecked for hours after a long run
What to drink, and when
Start with before. It is the window most people in running get wrong. For a normal training day rather than a race, the timing guide covers every window.
BEFORE
- 16 oz with a stick
- Nothing in the last 15 minutes
Start full so the first miles spend what you have, not what you are missing.
DURING
- A soft flask with a stick, 4–6 oz at a time
- Refill at a fountain and add a stick past the hour
Replaces the sodium going out so the calves stay loose past mile eight.
AFTER
- 24 oz per pound lost
- A salty snack, then a meal
Stops the lingering headache and buys back the afternoon.
The book’s running number: every pound you lose is 24 oz to put back, with sodium in it. Weigh yourself before and after one long run and you know your own bill for race day.
What to take, and what we do not sell
Two of these three are things we do not sell. A hydration stick does not fix fuelling, and pretending otherwise is how people end up disappointed.
Electrolytes
Fuel
Worth taking too
The questions we get about running
How much do you sweat in running?
20–40 oz of sweat an hour on a warm run. 500–1,000 mg of sodium out per hour for a salty sweater. Weigh in before and out after a session: every pound down is about 24 oz you did not put back.
When should I drink during running?
The hour before you run: 16 oz with a stick; Nothing in the last 15 minutes. Start full so the first miles spend what you have, not what you are missing.
What should I drink before running?
The hour before you run: 16 oz with a stick; Nothing in the last 15 minutes. Start full so the first miles spend what you have, not what you are missing.
How do I recover after running?
Within 30 minutes: 24 oz per pound lost; A salty snack, then a meal. Stops the lingering headache and buys back the afternoon.
Do I need electrolytes or is water enough?
Water puts back the fluid you sweat out. It does not put back the sodium, potassium and magnesium that left with it, and without sodium your body cannot hold on to the water. Per hour of hard work: Sodium 500–700 mg, Potassium 150–300 mg, Magnesium 30–60 mg, Water 16–24 oz.
How many sticks do I need?
One before. One per hour on the run. One after on long or hot days. Sip, do not chug. Small sips of a mixed flask every 15 minutes beat a full fountain stop that sloshes for a mile. The starter kit has 40 sticks in five flavors.
Do I need electrolytes for a 5K?
Not during it. Most 5Ks take less than 45 minutes. The book’s plan is one stick in 16 oz in the hour before you run, with nothing in the last 15 minutes. On a hot day, take one with your first bottle after.
How much should I drink during a half marathon?
Start sipping at 45 minutes. Take 4 to 6 oz from a flask mixed with a stick every 15 to 20 minutes. Past the hour, refill at a fountain and add a second stick. Do not drink more than you sweat. Gaining weight during a race is the main risk for low blood sodium, and plain water makes it worse.
Why do my calves cramp at mile 8?
By mile eight, a heavy sweater has lost close to 2% of body weight. Sodium has been leaving since mile one, and fountain water put none of it back. Cramps have more than one cause, and pace and tired legs count too. Still, this is where the book puts them. The fix is to start topped up and sip a mixed flask after 45 minutes. Here is why you cramp even when you drink water.
What should I drink after a long run?
Weigh yourself before and after. Drink 24 oz for every pound you lost, with a stick in the first bottle. Then eat a salty snack and a real meal. That stops the headache that hangs around for the rest of the day.
Everything in the box
The book this article came from is in there too. One page for every sport, so the next thing you take up is already covered.
Five flavors, one stick each
Taste is the one thing you have to try for yourself. The starter kit gives you all five, so you find the one you will actually reach for.
- All five minerals sweat costs you, no sugar. See the label.
- Informed Sport certified, batch by batch.
- Mixes into whatever bottle is already in your belt or vest.
