Water, rest, shade — and when salt matters on a hot shift.
Farm, construction, roofing, landscaping, and utility crews sweat for eight hours, not one studio class. Here is the CDC NIOSH and OSHA shift math: when cool water is enough, when prolonged sweating needs electrolytes, why fluid intake should generally stay under 6 cups (48 fl oz) an hour, the 20%-per-day new-worker ramp, and bulk kitchen-salt cooler recipes. Educational estimate, not medical advice.
One page to print for the crew: the heat sheet · en español: la hoja de calor para el equipo.
If a worker shows confusion, altered mental status, slurred speech, fainting, or seizures, call 911 immediately, move them to shade, remove outer clothing, and cool rapidly with a cold-water or ice bath if possible (or wet cloths/ice on head, neck, armpits, and groin). If a worker has muscle pain with dark tea- or cola-colored urine (suspected rhabdomyolysis), stop work at once and seek immediate medical care for a creatine kinase (CK) check.
Build a shift-timed crew heat sheet.
Run your shift duration, crew size, and day in the heat to get estimated cooler volumes, the NIOSH acclimatization cap for today, and bulk salt-and-citrus jug numbers. Everything runs in your browser; nothing is stored or sent.
Tailgate shift summary (8 hr shift · 6 workers · Day 1)
| Per-worker water | 1 cup (8 fl oz) every 15–20 minutes (24–32 fl oz/hr · 6–8 quarts across 8 hrs). Cool potable water <15°C (59°F) with individual cups. |
| NIOSH hourly ceiling | Generally no more than 6 cups (48 fl oz / 1.5 quarts) per hour. Over-drinking dilutes blood sodium (hyponatremia). |
| Crew cooler staging | Stage at least 9 to 12 gallons total across the shift (3 × 5-gallon coolers). |
| Electrolyte threshold | Electrolytes + meals needed (≥2 hr shift): Estimated sweat sodium loss ~935 mg/hr (~7,480 mg across 8 hrs). Provide balanced electrolyte drinks plus regular meals/snacks alongside plain cool water. Do NOT use salt tablets. |
| Acclimatization cap | Day 1 (New to heat): Max 20% of usual heat duration (1.6 hrs in heat). NIOSH 20% rule: no more than 20% on Day 1, adding at most 20% each day (100% on Day 5). Supervise closely for 14 days. |
| Bulk cooler mix | 1-quart jug: 1/4 to 1/2 level tsp table salt (~575–1,150 mg estimated sodium) + citrus squeeze. 5-gallon crew cooler: 1.5 to 2.5 level tbsp table salt (~500–850 mg estimated sodium/qt) + 3 cups citrus juice, always paired with a separate plain-water cooler. |
OSHA guidance (Water. Rest. Shade.; there is no final federal heat rule yet): when heat stress is high, employers should require breaks, in general hourly, in shade, a misted tent or an air-conditioned vehicle or room. Breaks in air conditioning do not hurt acclimatization.
The three numbers CDC NIOSH & OSHA actually set.
| Rule | Threshold & why it matters on a jobsite |
|---|---|
| 1 cup / 15–20 min | 8 fl oz every 15 to 20 minutes (24–32 fl oz/hr) of cool potable water <15°C (59°F) placed close to the work area with individual cups. Workers in the heat often fall behind if they wait until after the shift. |
| 2-hour line | Under 2 hours: cool potable water is sufficient (OSHA & CDC NIOSH). 2 hours or more of sweating: provide fluids containing balanced electrolytes plus snacks/meals, because prolonged sweating depletes salt as well as water. Never use salt tablets. |
| 6 cups/hr ceiling | Generally no more than 6 cups (48 fl oz / 1.5 quarts) per hour (CDC NIOSH). Chugging plain water or weak drinks past 48 fl oz/hr can dilute blood sodium below 135 mmol/L (hyponatremia). |
The 7–14 day heat acclimatization ramp.
Most outdoor heat fatalities happen in the first few days of working in hot conditions before sweat rate and sweat-salt conservation adapt. CDC NIOSH (Publication 2017-124) sets two distinct ramp schedules:
| Day in heat | New workers (no recent heat exposure) | Experienced workers (returning / new heat wave) |
|---|---|---|
| Day 1 | Max 20% of usual heat duration | Max 50% of usual heat duration |
| Day 2 | Max 40% (+20% max per day) | Max 60% |
| Day 3 | Max 60% | Max 80% |
| Day 4 | Max 80% | 100% |
| Day 5–14 | 100% on Day 5; closely supervise through Day 14 | 100% |
Kitchen-salt cooler recipes (nothing to buy).
When a crew sweats for 6 to 10 hours, plain table salt already in the kitchen does the job. Normal meals replace most daily electrolytes, and for mid-shift coolers you can mix bulk table salt and citrus in seconds. Always stage one plain cool-water cooler next to any salted cooler:
| Container | Bulk mix & estimated sodium |
|---|---|
| 1-quart personal jug (32 fl oz) | 1/4 to 1/2 level teaspoon table salt (~575–1,150 mg estimated sodium) + squeeze of lemon/lime or 2 fl oz 100% orange juice in cool water. |
| 5-gallon crew cooler (20 quarts) | 1.5 to 2.5 level tablespoons table salt (~500–850 mg estimated sodium per quart) + 3 cups 100% citrus juice in cool water. Label the cooler clearly and pair with a plain-water cooler. |
High blood pressure, heart or kidney disease, pregnancy, or low-sodium diet? Do not add extra salt on our say-so. Workers on blood-pressure medicines, diuretics, or sodium restrictions should bring their numbers to their clinician first via the printable clinician sheet →
Heat-illness first aid on the jobsite.
| Condition | Signs & CDC NIOSH / OSHA action |
|---|---|
| Heat Stroke (Call 911) | Confusion, altered mental status, slurred speech, fainting/coma, seizures, body temp 106°F+. Call 911 immediately, stay with worker, move to shade, remove outer clothing, and cool rapidly with a cold-water or ice bath (or ice/wet cloths on head, neck, armpits, groin). |
| Rhabdomyolysis (Medical care now) | Muscle cramps/pain with dark (tea- or cola-colored) urine, severe weakness. Stop activity at once, drink water, and go to a clinic/hospital for a blood creatine kinase (CK) check. |
| Heat Exhaustion (Cool & evaluate) | Headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating. Take worker to a clinic or ER for evaluation (or call 911 if unavailable); move to cool area, loosen clothes, give frequent sips of cool water. |
| Heat Cramps | Painful spasms in abdomen, arms, or legs. Rest in shade, drink water and have a snack or balanced electrolyte drink every 15–20 minutes. Avoid salt tablets. Get medical help if the worker has heart problems, is on a low-sodium diet, or has cramps lasting >1 hour. |
Primary sources, checked against the live pages 2026-10-26: CDC NIOSH Heat Stress Recommendations (NIOSH Pub 2016-106 & 2017-124); OSHA Occupational Heat Exposure: Water. Rest. Shade.; CDC NIOSH Heat-Related Illnesses & First Aid.
Keep reading
Before you add salt
High blood pressure, heart/kidney conditions, or diuretics? Print the clinician question sheet.
Can you drink too much water?
Why chugging plain water past your losses dilutes blood sodium below 135 mmol/L.
Make your own mix
Milligram-by-milligram table salt, potassium, and magnesium math.