IRONMAN Switzerland Thun

Arrive early, get a few minutes in the water to settle your breathing, then do 3–4 short accelerations (10–20 seconds hard, easy back) to find your stroke rhythm. Choose your start position based on your planned swim effort so you’re not sprinting in the first congestion. In the first few minutes, focus on smooth cadence and controlled breathing—avoid getting dragged; your goal is to stabilize into a repeatable pace before mid-swim.

You’re swimming 3,866 m in freshwater where temperature varies, so your early effort should be slightly conservative until your body warms up and settles. Expect the pack to sort out over the first portion—find clean water, then lock in your stroke and aim for consistent intervals rather than reacting to every surge. If wind influences surface conditions, it can create irregular chop or directional drift, so keep your line and sighting habits disciplined to avoid zig-zagging. Fueling during the swim is typically minimal, so conserve your energy and be ready to transition quickly and calmly into the bike.

Plan a smooth swim-to-bike flow: exit efficiently, hydrate if needed, then focus on getting shoes and bike on without overthinking—transition time is about staying calm and ready. After mounting, pedal easy for the first segment and let your breathing come down before you start pushing. In the first 10–20 minutes, keep power/effort controlled while the route finds its rhythm over climbs; you’ll be climbing for a long time on a course with 1,712 m of gain.

The bike is 178.8 km with a hilly, climbing profile (1,712 m gain), so ride like the hills are spaced throughout the day rather than “surprises.” With light wind (2.2 m/s from the N) you’ll still feel effects on exposed sections—stay patient into headwind segments and don’t spike power just to ‘win’ the wind. In moderate heat, prioritize steady intake: target 90 g carbs per hour, 750 mg sodium per hour, and about 650 ml fluid per hour, starting early and keeping it consistent rather than trying to catch up later. Use the climbs to fuel (not just chase power); take your planned bottles/gels during accessible portions so you don’t disrupt cadence. On downhills or turns, stay stable and don’t slam the brakes unnecessarily—preserve legs for the next climb and keep nutrition on schedule.

In T2, aim for a quick changeover without rushing—rack your focus on getting your shoes on cleanly and standing tall as your feet hit. Immediately after mounting the run, expect your legs to feel different: the quads will be “reloaded” by the bike climbs, and the first few minutes can feel flat or stiff. Start the run controlled—slightly easier than you think—so your breathing matches the pace before you commit.

The run is 42.2 km with the elevation profile listed as unknown, so assume undulations and pace accordingly rather than anchoring to flat-course expectations. With moderate heat and a light N wind, you may not feel extreme conditions early, but dehydration and heat stress can build—use the fueling and fluid plan you established on the bike so you don’t fade late. Aim to carry your nutrition rhythm forward: keep taking carbs and fluids on schedule and keep sodium coming through the day to manage cramping risk. Since terrain details aren’t specified, stay responsive to how your effort feels on each section: if the ground turns slightly uphill, reduce pace a touch and keep form tall; if it flattens, you can stabilize back into goal rhythm without dramatic surges. Watch your breathing and stride length—late-race pacing on an unknown profile is mostly about staying smooth and not overstriding when tired.