Neptune Challenge takes place on Sat, Jun 26, 2027 in Copenhagen, Denmark. The main route is 1.5 km.
- Date
- Sat, Jun 26, 2027
- Start
- Copenhagen 🇩🇰
- Distance
- 1.5 km
- Level
- Open to all
Your 38-week plan to Neptune Challenge
The Base phase starts this week. Built around your fitness and adjusted every day as your form changes; attach the course and it prepares for the climbs too.
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Participants swim 1.5 km every hour for a chosen duration ranging from 6 to 42 hours at Amager Strandpark in Copenhagen.
What this race demands
The Neptune Challenge demands sustained aerobic endurance and exceptional recovery capacity to complete multiple repeated swimming intervals over an extended duration.
Intermittent endurance
Athletes must perform a 1.5 km swim every hour for a duration ranging between 6 and 42 hours, requiring consistent pacing and efficient energy expenditure during each effort.
Short recovery window
The hourly start interval leaves limited time between efforts for nutrition, physical recovery, and mental reset before returning to the water.
Extended time on feet
Operating across multi-hour durations places high cumulative stress on the muscular and nervous systems, demanding robust durability.
Given the minimum six-hour duration and repeating hourly efforts, athletes should consume 60 to 90 grams of carbohydrates per hour using liquid or easily digestible sources during rest periods to maintain glycogen stores.
Your road to race day
Race day at Neptune Challenge is 38 weeks away. This is how a coach divides that time. The first phase starts now.
01Base26 weeks · Oct 4, 2026 – Apr 3, 2027
Aerobic foundation: mostly steady endurance work that grows the aerobic engine and the durability the later phases stand on.
02Build6 weeks · Apr 4, 2027 – May 15, 2027
Progressive overload: training load climbs in waves, with harder weeks stacked on the base and planned recovery weeks that let the gains land.
03Peak3 weeks · May 16, 2027 – Jun 5, 2027
The hardest weeks of the plan: race-specific intensity at nearly full training load, sharpening exactly what this race asks for.
04Taper2 weeks · Jun 6, 2027 – Jun 19, 2027
Volume drops while intensity stays: short, sharp efforts keep the legs awake as fatigue drains away.
05Race week1 week · Jun 20, 2027 – Jun 26, 2027
Openers, rest and logistics. The work is done; the job now is arriving fresh.
Frequently asked questions
When is Neptune Challenge?
Neptune Challenge takes place on Sat, Jun 26, 2027 in Copenhagen, Denmark.
How long is Neptune Challenge?
The main route is 1.5 km.
What does Neptune Challenge demand?
The Neptune Challenge demands sustained aerobic endurance and exceptional recovery capacity to complete multiple repeated swimming intervals over an extended duration.
Who is Neptune Challenge for?
Neptune Challenge is open to all participants.
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