The 70.3 Rio Run: 3 Flat Laps Around Aterro do Flamengo

The course

21.1 km over 3 laps around Aterro do Flamengo, right by the beaches. Mostly flat: this is a half marathon you run by pace, not one you manage on the climbs. The multi-lap format cuts both ways: you see the crowd three times and can mentally break the race into blocks, but you need to count your laps correctly and know where the course splits off toward the finish.

The weather: not the heat you're expecting

August 8 in Rio is the southern hemisphere winter. The official page lists an air temperature range of 21–29°C; typical forecasts call for highs around 24–26°C in the early afternoon, with low humidity. Translation: manageable running conditions, far from the tropical furnace the name "Rio" conjures up. That's not a free pass to ignore hydration, but you don't need a full hot-race protocol either. If you hit the run course between late morning and early afternoon, you'll be running in the hottest hours of the day: plan accordingly, especially if your projected finish time is over 6 hours.

Pacing over 3 laps

The classic trap on flat lap courses: going out too hot on lap one, carried by the adrenaline of T2 and the crowd. On a flat course there's no climb to slow you down automatically: you have to rein yourself in.

A concrete plan:

• Lap 1: controlled pace, 5-10 seconds per km slower than target. Use the lap to read the course: where the aid stations are, where the wind shifts, where the split points are.
• Lap 2: goal pace, steady.
• Lap 3: if you've managed it well, this is where you spend what's left.

To give you a ballpark, our rough estimates (not official data) put the run split between 2:30 for a relaxed finisher and 1:30 for a top age-grouper, with 2:05 and 1:45 for the intermediate goals.

Counting laps: a system, not your memory

After an ocean swim and 90 km on the bike, your memory isn't reliable. Pick a system before race day:

• Rubber bands on your wrist to move at each pass, or
• A manual lap on your watch at a fixed point on the loop, or
• A simple reference: "the third lap starts at 14 km total."

And study the map for the exact point where the course splits between "new lap" and "finish." There are signs on race day, but knowing it beforehand takes one thing off your mind.

Aid stations and cutoff

The available sources give no details on the number or contents of the run aid stations: that information is not available in this guide. Check the official athlete guide when it's released and don't plan your hydration on assumptions. The overall race cutoff is 8h30 per the local rules: if your splits are near the limit, work out what time you need to be out of T2 to finish with as little walking as possible.

What to do between now and race day

1. Train bike-run bricks with a controlled start: the first 2 km of the run at a held-back pace need to become automatic. 2. Test your lap-counting system in a long training run on a loop course. 3. Do at least one key run at the time of day you'll be running on race day, to get used to early-afternoon temperatures. 4. Set a "plan B" pace to adopt if the bike went over your planned watts: deciding it beforehand means you won't be improvising on lap 1.