Supplements for Runners — Running Nutrition | 6AM Run

There's a version of race morning every marathoner knows. You're standing in the corral, you've already hit the porta-potty line three times, and you still can't tell if you drank too much or not enough. Your stomach is sloshing, your mouth is dry, and the race hasn't even started.

I've been there. Early in my marathon life I treated hydration like a race-morning task: wake up, chug a giant bottle of water, hope for the best. Some races I felt flat by mile 10 and couldn't figure out why. Others I was hunting for a bathroom by mile 6.

Here's what changed everything for me: hydration is not a race-morning problem. It's a race-week system. By the time you're standing on the start line, the work is either done or it isn't. This is the simple plan I now use — and the one I teach every runner I coach through their taper.

1. Why the week matters more than the morning

Your body absorbs water steadily, not instantly. Drink a huge amount in the final two hours before a race and most of it goes straight through you — that's the porta-potty line. Worse, flooding your system with plain water dilutes your sodium, and low blood sodium (hyponatremia) is a real medical risk in marathons, not a theoretical one.

Start the race even slightly dehydrated and the opposite problem shows up: your heart rate drifts higher at the same pace, the effort feels harder than it should, and your stomach gets pickier about fuel exactly when you need it most.

The goal for race week is boring and specific: arrive at the start line with normal fluid levels and full sodium stores. Not waterlogged. Not topped off to bursting. Just ready.

2. Days 4 to 2 out: normal, plus a little

The taper already cuts your training volume, which quietly cuts how much you drink — no long run means no big post-run refill habit. That's the trap. Keep your intake deliberate:

• Carry a bottle all day. A simple floor for most runners is roughly half your body weight in ounces of fluid per day (a 150 lb runner: ~75 oz), spread out, not chugged.
• Check the simple gauge. Pale yellow urine means you're on track. Dark and scant means drink more. Completely clear all day means you're probably overdoing plain water.
• Add electrolytes once a day. One electrolyte drink daily in the final few days helps your body actually hold onto the fluid instead of passing it.
• Salt your food normally — or a touch more. This is not the week for a low-sodium "clean eating" experiment.

Pair this with your food plan and you're stacking the two halves of race week together. Our guide to Taper Week Nutrition covers the eating side day by day.

3. The day before: front-load, then taper off

The day before the race, drink steadily through the morning and early afternoon — then ease off after dinner. You're not cutting fluids; you're timing them so you sleep through the night instead of getting up three times.

• Morning to mid-afternoon: drink on a schedule, a glass every hour or so, with an electrolyte drink at lunch.
• Dinner: eat salty, carby, familiar food and drink to thirst with the meal. (The full menu is in our night-before-a-marathon guide.)
• Evening: small sips only. Set out tomorrow's first bottle tonight so there's no thinking at 4 AM.

4. Race morning: the exact timeline

Race morning hydration is a timeline, not a volume contest:

• Wake-up (2.5–3 hours before the start): drink 16–24 oz (500–700 ml) of water with electrolytes right away, before coffee, before anything.
• Next 90 minutes: sip to thirst alongside your normal pre-race breakfast. Your urine should be pale yellow before you leave.
• 45–60 minutes out: stop the big intake. This is what saves you from the mile-2 bathroom stop.
• ~15 minutes out: a small 4–8 oz top-up if your mouth feels dry. Then you're done — trust the week.

On my own race mornings, that first bottle is where I keep it simple: water plus an electrolyte mix. I use HydraBlast because it goes down easy at 4 AM, it's not overly sweet, and it covers the sodium side of the equation in the same glass — one less thing to think about before a race. Then, about 30 minutes before the gun, I take my usual pre-run fuel — MARATHON is my go-to — exactly like I've done in training. Whatever brands you use, the rule stands: nothing new on race day.

5. Sodium: the half of hydration most runners skip

Sweat isn't water. It carries roughly 500–1,500 mg of sodium per liter, and that sodium is what holds fluid in your blood where it does its job. Drink water without sodium all week and your body simply lets more of it go.

Practical version: salt your meals, have one electrolyte drink a day during race week, and have a second on race morning. If you're a salty sweater — white crust on your hat, stinging eyes, gritty skin after long runs — you sit at the high end of that range and should take sodium more seriously than most. I broke down the numbers in How Many Electrolytes Do Runners Actually Need? if you want to work out your own range.

6. During the race: small, early, on a rhythm

• Start early. Take your first sips by mile 2 or 3, not when you first feel thirsty at mile 9.
• Little and often. A few mouthfuls at most aid stations beats a full cup at every third one — your stomach absorbs a steady trickle better than a flood.
• Alternate water and sports drink where both are offered, and take your fuel with water, not sports drink, so the sugar concentration stays where your gut expects it.
• Never gain weight mid-race. If you're drinking so much you're heavier at mile 18 than at the start — sloshing stomach, tight rings — you're overdrinking. Ease off.

Fueling and hydration run on the same schedule; our NYC Marathon Fueling Guide shows how they fit together station by station if you're racing New York this fall.

Race week hydration mistakes to avoid

• The night-before gallon. Chugging water late wrecks your sleep and dilutes sodium. Front-load the day instead.
• A brand-new electrolyte product on race morning. Test everything in training. Nothing new on race day, ever.
• Letting taper week quietly dehydrate you. Less running means less automatic drinking. Keep the bottle habit even when mileage drops.
• One plan for every forecast. A 75-degree start needs noticeably more fluid and sodium than a 45-degree one. Adjust the plan to the weather, not your hopes.
• Ignoring the scale. Weigh yourself a few mornings this week. If you're drifting down 2–3 pounds without trying, you're behind on fluids.

Your race week hydration checklist

1. Days 4–2 out: bottle in hand all day, pale-yellow check, one electrolyte drink daily.
2. Day before: front-load by mid-afternoon, salty familiar dinner, small sips after.
3. Race morning: 16–24 oz with electrolytes at wake-up, sips after, big intake stops 45–60 minutes out.
4. Small 4–8 oz top-up ~15 minutes before the gun, only if your mouth is dry.
5. In-race: first sips by mile 2–3, little and often, water with fuel.

The bottom line

Nobody wins a marathon in the porta-potty line, and nobody PRs their way out of a hydration hole at mile 18. Race week hydration is unglamorous: a bottle you keep refilling, some salt on your food, one honest timeline on race morning. Do it for four days and the start line feels calm instead of frantic — and the last 10K gets the version of you that you trained for.

See you out there at 6AM.

— Hami, 6AM Run