I have killed every plant I’ve ever owned. Every single one. A succulent that was supposed to be indestructible? Dead in three weeks. A snake plant that my friend said “only needs water once a month”? I watered it once a month, but apparently I was supposed to give it sunlight too. Who knew. My apartment looks like a botanical crime scene. Brown leaves, dry soil, the whole sad thing.
But I own two paddleboards. A 10‑foot rigid board for flat days, and an inflatable one for travel. I’m on the water almost every weekend, sometimes before work. I know exactly how much fluid I lose paddling in 85% humidity. I know my sweat rate down to the milliliter. I just can’t keep a cactus alive.
That’s the thing about Miami. The climate here is a hydration laboratory. It’s also a plant cemetery, apparently.
I moved here five years ago from Gainesville, which is hot but not humid in the same suffocating way. In Gainesville, sweat evaporates. In Miami, it just sits on your skin like a wet blanket. You keep sweating and sweating because your body is trying to cool off, but the sweat doesn’t evaporate, so you don’t cool down, so you keep sweating even more. It’s a feedback loop from hell.
My first summer here, I went for a casual 5‑mile paddle on Biscayne Bay. Nothing intense. Just a float, really. I brought a 20‑ounce water bottle, which back in Gainesville would have been plenty. I finished the paddle feeling like garbage. Headache, heavy legs, dark urine when I got home. I lost almost 2 kilograms (4.4 pounds) of water weight in two hours. That’s about 2 liters (68 ounces) of sweat. I had only drunk 600 milliliters (20 ounces).
That’s when I learned that Miami is not “temperate plus a little.” It’s a whole different beast. My baseline water calculation used to be 30 milliliters per kilogram of body weight. That’s the standard formula. For me at 65 kilograms (143 pounds), that’s about 1.95 liters (66 ounces) per day. But that baseline assumes a temperate climate. Miami is tropical. My climate adjustment factor is 1.3 — meaning I need 30% more fluid just to exist here, before I even do any activity.
Then add the paddleboard activity. Moderate intensity for two hours adds about 1.5 liters (50 ounces) of fluid needs. So my daily total on paddle days is around 1.95 liters times 1.3 plus 1.5 liters equals about 4 liters (135 ounces). That sounds like a lot. It is a lot. But I’ve measured my sweat rate. It’s real.
I figured this out by doing the sweat test I recommend to everyone. Weigh yourself naked before exercise. Do your activity. Don’t drink anything during — or if you do, weigh the bottle before and after. Towel off completely and weigh yourself again. The difference in grams is roughly the milliliters of sweat lost. For a one‑hour run in Miami summer, I lose about 1.2 liters (40 ounces). For paddling, it’s a little less because of the breeze, but still around 1 liter per hour.
So now I have a paddleboarding kit. A 32‑ounce (950‑milliliter) insulated bottle with electrolytes already mixed. A smaller 16‑ounce (475‑milliliter) bottle of plain water, “the baseline,” for when I just need a quick rinse of the mouth. Salt tablets in a tiny waterproof container. And a hat. The hat does nothing for hydration but it keeps the sun off my face.
I drink 500 milliliters (17 ounces) of electrolyte solution before I even put the board in the water. Then I set an alarm on my watch for every 20 minutes. Each time it buzzes, I take four big swallows from the big bottle. That’s about 150 milliliters (5 ounces). Over two hours, that’s 900 milliliters (30 ounces) of electrolyte drink, plus the 500 pre‑load, total 1.4 liters (47 ounces). That almost matches my sweat loss of about 2 liters. The remaining 600 milliliters (20 ounces) of deficit comes from the plain water I sip and from the fact that my body can also absorb some fluid from my pre‑hydrated state.
The electrolytes are non‑negotiable here. When you sweat 2 liters in two hours, you’re losing about 1,000‑1,500 milligrams of sodium. Plain water doesn’t replace that. If I only drank water, I’d dilute my blood sodium and end up with the same bloated, crampy feeling Derek had in the Ironman. So I use a tablet that gives me about 300 milligrams of sodium per 500 milliliters of water. Two tablets over two hours gives me 600 milligrams. Then I eat a salty snack afterwards — pretzels or pickles — to top off the rest.
The irony is not lost on me. I can calculate my sweat sodium concentration in my sleep. I can tell you exactly how much fluid a 200‑pound man needs during a hot yoga class. But I cannot remember to water a plant. My friends send me photos of their thriving monstera plants and I feel a weird mix of pride for them and shame for myself.
I think it’s because plants don’t send you signals. A plant just goes from green to brown silently. A human body gives you headaches, dry mouth, dark pee, fatigue. It yells at you. I respond to yelling. I don’t respond to quiet suffering. That’s probably something I should work on.
But here’s what I’ve learned from living in Miami that applies to everyone, not just paddleboard people. Climate matters more than most hydration calculators admit. A lot of the online tools just ask “activity level” and “body weight” and spit out a number. They ignore the fact that sitting in 90‑degree heat with 80% humidity is physiologically closer to light exercise than to rest. Your body is working to cool itself even if you’re just walking to your car.
So I built a climate adjustment into my calculator. Tropical gets 1.3x baseline. Desert gets 1.2x (dry heat still makes you sweat, but at least it evaporates). Temperate gets 1.0. Cold gets 0.9 because you lose less fluid through sweat but you still lose through respiration. That cold, dry air sucks moisture out of your lungs.
Daily Water Intake Calculator
Includes climate adjustment for tropical, desert, temperate, and cold. Also adds activity and altitude.
All data stays in your browser — we never see it.
Exercise Sweat Loss Estimator
Perfect for Miami paddleboarding, running, or any outdoor activity in humid heat.
All data stays in your browser — we never see it.
