IRONMAN 70.3 Rio de Janeiro

Get to the swim start early, get your shoulders and hips warm, and practice a smooth, repeatable stroke before you line up. Seed based on your realistic 400–500m comfort so you’re not forced into constant passing early. In the first few minutes, settle quickly: keep your cadence controlled, sight early and often, and avoid sprinting off the start while the field compresses. If there’s any chop, prioritize balance and straight-line body position over trying to force power through waves.

You’ll swim 1902m in ocean water around 22.7°C, with wetsuit legality depending on the official race ruling set on race morning—confirm in the IRONMAN athlete guide. Expect a typical open-water start where congestion can slow your first strokes; your goal is to find clear water, then build into your effort rather than chasing every surge. With the easterly wind (4.9 m/s), the surface can chop unevenly, so stay calm on the breath and keep your stroke long enough to track through small wave patterns. Fueling during the swim isn’t the focus—save your carb/sodium/fluid plan for the bike and run—so think “smooth finish,” not “power sprint.”

Plan a fast, organized T1: know where your gear is laid out, get your wetsuit off efficiently (if worn), and get shoes secured before you fully settle your posture. Ride out of T1 immediately with a calm cadence for a few minutes—don’t spike power right away because you’ll be climbing and rolling soon. Once you’re moving freely, settle into your fueling routine early so you’re never “playing catch-up.” Expect traffic and positioning matters early; find a stable group or lane that matches your speed and passing comfort.

The bike is 90 km with ~491 m of rolling elevation, so pacing matters: hold steady power on the rises and avoid over-revving on every short kicker. The easterly wind (4.9 m/s) can create side-to-headwind moments, so keep your line smooth, don’t fight the bars, and use small adjustments to stay aerodynamic without rocking the bike. In moderate heat (air 18.3–25.1°C), you still need consistent fluid—don’t wait until you feel thirsty. Stick to your target fueling per hour: 90 g carbs, 1000 mg sodium, and 800 ml fluid per hour, using the early stretches of the course to hit the rhythm. As the course rolls, treat each aid station as part of the plan: drink first, then carbs, then keep moving—aim to never let intake fall apart when you’re working a climb.

In T2, focus on getting upright quickly and making your first steps feel controlled—not rushed. Transition strategy: start the run with shorter, lighter strides to re-engage your glutes and hamstrings, and let your legs settle for the first few minutes before you tighten form. Since the run is rolling (21.1 km, ~96 m gain), commit to pacing that matches effort, not just pace on the flatter segments. Have your first planned drink/food ready right after you’re settled so you don’t lose momentum.

The run is 21.1 km with ~96 m rolling elevation—expect subtle ups and downs rather than long brutal climbs, so your best pacing is “effort-based.” With moderate heat (18.3–25.1°C), hydration and sodium consistency become the limiter, especially as you pass through aid stations tired and tempted to skip. Your wind is still relevant: with an easterly wind, some portions can feel cooler and others can feel more exposed on open stretches—keep your breathing calm and don’t let the gusts change your posture. Keep your fueling consistent with your race targets—carbs, sodium, and fluid on a schedule—so you don’t fade during the middle of the run when rolling terrain is hardest to manage. If you’re monitoring effort, aim to keep effort stable on the rises and let pace float slightly rather than forcing it; in a rolling profile, that preserves your finish.