Ten hours of sweat on coffee and energy drinks. The 2 am calf cramp is where that bill shows up.
Roofers, framers, landscapers and warehouse crews can sweat more than a gallon on a summer shift, and most start it on coffee and an energy drink. Here's how to get to the end of the day with something left.
Coffee and an energy drink in the morning and one water at lunch leave most crews dried out by early afternoon. That's the headache, the 3 pm drag, the short fuse and the cramp in bed. Mix a stick into your bottle at 6 am, one at every break and one on the drive home (five or six on a hot day), and you put back what the heat takes before it catches up with you.
A July roof takes 3,000 mg of salt or more out through sweat. Water alone leaves you 3,000 mg short by the drive home. That is the 2 am calf cramp. A stick at every break puts it back as you go.
Sweat is more than water. It's salty, and that salt is what your body needs to hang on to the water you drink.
Every drop of sweat takes some salt with it, and your body uses that salt to hold on to water. Lose enough of both and your heart has to work harder to do the same job, you run hotter, and your muscles are quicker to cramp. That's the afternoon drag, the head rush when you stand up off your knees, and the cramp that wakes you at night.
Plain water puts the water back but not the salt, so a lot of it runs straight through you. The fix is water with the salt and minerals you sweated out back in it.
On a job site you barely see it happen. The sweat dries on your shirt, and all you notice are the salt rings. When the refill is plain water, your body sees the watered-down blood, decides it has enough and sends the rest to your bladder. That's how you can drink a lot, pee all afternoon and still end the day with a headache and cramps in bed.
Energy drinks all morning and water only at lunch. Sodium goes in with the water or the water goes straight through.
Same job, same heat. The only thing that changes is what's in your bottle. Here's a summer shift on coffee and one water at lunch, and the same shift with a stick at every break.
Coffee and an energy drink, no water. You're already behind.
16 to 20 oz with a stick, then the coffee.
Shirt soaked through, salt rings showing, still no water.
A stick in the bottle. Salt and water go back in together.
Headache building. Heart pounding on the same work. The lunch water runs straight through.
No early-afternoon headache.
Foggy, short-tempered, sloppy.
Same pace at 3 pm as 7 am.
Salt rings dried white on the hat and the shirt.
20 oz with a stick on the way home, then a salty dinner.
A calf or foot cramp wakes you up.
No 2 am calf cramp.
Wrecked.
Friday feels like Monday.
Both columns come from The Hydration Playbook. The right-hand column is what the book says changes once the salt goes back in with the water.
You don't have to be soaked through for it to show. Lose about 1.5% of your body weight in sweat and people in studies got tired, tense and foggy. For a 200-lb worker that's three bottles of sweat, and on a summer site that's gone well before lunch.
More tired, more tense, harder to focus, and the work feels harder. The women in one study also got more headaches.
Ganio et al., 2011 · Armstrong et al., 2012Pooled across 28 studies, being dried out cut how long muscles could keep going by about 8%.
Savoie et al., 2015For a 200-lb worker, 1.5% of body weight is 3 lb, about three 16 oz bottles, and 2% is 4 lb, about four. With nothing going back in, an average sweater gets there about 3 and 4 hours into the shift. If you sweat a lot, it's about 1.5 and 2 hours.
The coffee and the energy drink are shown but not counted in the ounces.
That's about five sticks on a hot day: one at 6 am, one at each break, one at lunch and one on the drive home. Above 85°F the book says one every hour.
Drinking more only helps if there's enough salt in it. Without it, the extra water goes straight through you.
Shirreffs et al., Med Sci Sports Exerc, 1996Most of the 39 miners in one study showed up for 10 to 12.5 hour shifts in serious heat already dried out. The ones who knew the risk and kept drinking through the shift didn't fall any further behind.
Brake & Bates, Occup Environ Med, 2003Heat can hurt you, and a stick in your bottle doesn't fix heat illness. Shade, breaks and easing into the first hot week of the year are what protect a crew. If someone gets confused, stops making sense or passes out in the heat, call 911.
The book puts every trade at 16 to 32 oz an hour in summer heat. What changes from job to job is where the heat comes from, when you can stop, and where a bottle can sit.
Roofers
Framers
Concrete finishers
Landscapers
HVAC and electricians
Warehouse crews
| Sun overhead | Heat off the surface | Still air | Water out of reach | |
|---|---|---|---|---|
| Roofers | ||||
| Framers | ||||
| Concrete finishers | ||||
| Landscapers | ||||
| HVAC and electricians | ||||
| Warehouse crews |
Researchers followed construction workers on summer sites for three days. Their hearts worked hardest and they were most dried out in the first half of the afternoon, and more of them ran dry as it went on because they weren't drinking enough.
Researchers had men sweat off 2% of their body weight in the heat, gave them a drink, then tested how easily a muscle could be made to cramp.
Blood salt dropped after the plain water and held steady after the electrolyte drink. It was a lab test on 10 men, and the needles show which way things moved and roughly how far.
Pooled from studies of workers in 30 countries. Most days means at least six hours a day, five days a week, two months a year.
Start with the breaks. That's where most crews fall behind. The whole day is laid out below, and if you train after work, the timing guide covers that too.
Start full; the roof will take a gallon whether you brought it or not.
Replaces the sodium going out so the afternoon does not fall apart.
Stops the night cramp and sets up tomorrow’s shift.
Every pound off the scale is 16 oz to put back, and it needs salt in it. Step on the bathroom scale before the truck in the morning and again when you get home, and you have your own number for the next hot day.
We only sell one of these three. A stick doesn't replace a real breakfast or a full night of sleep, and we won't pretend it does.
The book puts sweat at 16 to 32 oz an hour on a summer job site, which is more than a gallon over a ten-hour shift. You can't catch up on that at lunch. Start with 16 to 20 oz and a stick in the truck, put a stick in your bottle at every break, and go to one every hour once it's over 85°F.
Water puts back the water but not the salt you sweated out, and without the salt a lot of it goes straight through you. Drinking more only helps if the drink has enough salt in it (Shirreffs et al., 1996). On a long hot shift you need both.
They help your body hang on to the water you drink, and that matters sooner than most people think. In lab studies, losing about 1.5% of body weight in sweat, around three 16 oz bottles for a 200-lb worker, left people more tired, more tense and less focused (Ganio et al., 2011; Armstrong et al., 2012). Keeping salt and water going back in through the day is how you stay ahead of that.
Headaches have plenty of causes, and being dried out is a common one. Women who lost about 1.4% of their body weight in sweat reported more headaches and a harder time concentrating (Armstrong et al., 2012), and construction workers in a summer study were most dried out in the first half of the afternoon (Ueno et al., 2018). If the headaches keep coming even when you're drinking, see a doctor.
A hot day takes water and salt out together, and the refill is usually plain water. In a lab study, plain water after a hard sweat made muscles cramp more easily, and an electrolyte drink did the opposite (Lau et al., 2019). Put salt back in with the water through the day, and have one stick in 20 oz on the drive home. If the cramps keep coming, talk to a doctor.
They don't replace water and salt. The book says coffee before 10 am and water with a stick after that, because caffeine late in the shift cuts into your sleep, and a short night makes the next hot day harder. A sleeve of sticks in the truck costs less than a day of energy drinks.
One at 6 am, one at every break and one on the drive home. That's five or six on a summer day, and fewer on a cool one. Keep a sleeve in the truck so you're never without one.
On a hot day you sweat a lot of it out. The book puts it at 3,000+ mg of sodium on a July roof, and five sticks put back 3,000 mg. On a cool day or a day off you need fewer. If you have high blood pressure, heart or kidney problems, or you've been told to cut back on salt, check with your doctor first.
The book this article came from is in there too, with a page for every sport and every job.
Taste is the only part of this you can't take our word for. The starter kit gets you all five, so you find the one you'll actually reach for at 2 pm on a roof.
