How Should Swimmers Fuel for Training and Competition?

Key Takeaways

• Carbohydrate requirements for swimmers range from 3–5g per kilogram per day for lighter sessions to 6–10g per kilogram for high-volume or double-session training days.
• Swimmers can lose more than 1.5 litres of fluid per hour through sweat; keeping a drink bottle at the end of the lane and sipping between sets is the most practical way to maintain hydration across long sessions.
• Energy gels and chews are well-suited for poolside fuelling during sessions longer than 60 minutes and for topping up energy stores between heats on competition days.
• Post-session recovery nutrition combining carbohydrate and 20–25g of protein within 30–60 minutes supports glycogen resynthesis and muscle repair, particularly critical for swimmers completing two sessions per day.
• Open water swimmers competing in events lasting longer than 90 minutes should plan in-race carbohydrate intake of 30–60g per hour and prioritise electrolyte drinks over plain water at feeding stations.
• All Science in Sport energy, hydration, and recovery products are batch-tested through the Informed Sport programme, providing competitive swimmers with assurance against inadvertent banned-substance risk.

How Do Energy Demands Differ Between Swimming Events?

Swimming energy demands vary significantly by distance and format. Sprint events of 50–100 metres rely primarily on the phosphocreatine and glycolytic systems for rapid, short-duration energy; middle-distance events of 200–400 metres blend anaerobic and aerobic pathways; longer pool distances and open water events depend on sustained aerobic metabolism fuelled by carbohydrate and fat. High-volume squad sessions over multiple kilometres demand substantial carbohydrate availability throughout, meaning a one-size strategy will underserve either the sprinter or the distance swimmer. Carbohydrate is the primary fuel for moderate-to-high intensity swimming; glycogen depletion during long sets reduces swim speed, stroke coordination, and technical quality.

How Much Carbohydrate Do Swimmers Need?

Daily carbohydrate requirements for swimmers depend on training volume and intensity: 3–5g per kilogram of body weight for low-volume or technique-focused sessions, rising to 6–10g per kilogram on high-volume or double training days, consistent with Australian Institute of Sport (AIS) athlete nutrition guidelines. Understanding swimming nutrition from an energy and carbohydrate perspective helps swimmers match intake to effort across the week. For sessions exceeding 60–75 minutes, consuming carbohydrate during training sustains energy output and maintains stroke quality late in the effort. Energy gels and chews are practical poolside options, compact, fast-absorbing, and easy to take between sets without interrupting training. Carbohydrate periodisation, aligning higher intake with harder training days and lower intake with recovery days, supports adaptation across a training block without requiring rigidity in daily planning.

What Should Swimmers Eat Before Training or Competition?

The meal before a session or competition provides the glycogen foundation for performance. A carbohydrate-based meal eaten two to three hours before training, moderate in protein, low in fat and fibre, supports glycogen stores without causing digestive discomfort during the session. For early morning training where a full meal is not practical, a smaller carbohydrate snack eaten one hour before, such as white bread with a light filling, a piece of fruit, or a carbohydrate gel, is an effective alternative. On competition days, full glycogen stores and a settled stomach are the priority; between heats and finals, small carbohydrate snacks or energy gels maintain energy availability without digestive risk. For caffeine, the GO Caffeine Shot provides 150mg per 60ml serving, one serving per session maximum, and not recommended for those with caffeine sensitivity.

How Much Should Swimmers Drink During Training?

Swimmers frequently underestimate fluid losses because immersion in water masks sweat perception. Sweat rates of 0.4 to more than 1.5 litres per hour have been recorded in competitive swimmers depending on pool temperature, session intensity, and individual variation, according to sports science research published on swimmer hydration by the Australian Institute of Sport. Cumulative fluid losses can impair performance and increase perceived effort even in the absence of thirst. Drinking to thirst is a reasonable guide for recreational swimmers, but competitive athletes training multiple sessions per day benefit from a structured approach; keeping a drink bottle at the end of the lane and sipping between sets maintains hydration without interrupting training flow. Electrolyte replacement becomes important for sessions exceeding 60 minutes, particularly in heated indoor pools: sodium, the primary electrolyte lost in sweat, supports fluid retention and plasma volume. Electrolyte powders and hydro tablets can be added to a drink bottle to replace both fluid and sodium across the session.

What Should Swimmers Eat After Training?

Recovery nutrition in the first 30–60 minutes after a session is when glycogen resynthesis rate is highest and when muscle repair begins. A post-swim meal or snack should combine carbohydrate to replenish glycogen stores with 20–25g of protein for muscle repair; understanding optimal protein intake alongside carbohydrate in the first hour is consistent with AIS guidance for athletes under high training loads. This window is especially important for swimmers completing two sessions per day, where inadequate recovery nutrition between sessions compounds glycogen depletion over time. When whole food is not accessible immediately after training, a common situation at early-morning or evening squad sessions, a recovery supplement combining carbohydrate, protein, and electrolytes in one serving provides a convenient alternative. Science in Sport recovery products are formulated for this and batch-tested through the Informed Sport programme.

How Do You Fuel for Open Water Swimming?

Open water swimming adds nutritional challenges that pool events do not: distances ranging from 1km to 10km or more, nutrition accessed mid-race from feeds or carried on the body, and combined demands from cold water, currents, and sustained aerobic effort. For events lasting more than 60–90 minutes, a starting target of 30–60g of carbohydrate per hour maintains energy output; energy gels are well-suited to open water, compact, fast-absorbing, and practical to carry. For very long events where higher carbohydrate delivery rates are needed, BETA Fuel by Science in Sport provides 80g of carbohydrate per serving via a 1:0.8 maltodextrin-to-fructose dual-source formulation, enabling absorption rates that single-source carbohydrate products cannot achieve. At feeding stations, prioritise electrolyte drinks over plain water to replace sweat-lost sodium alongside fluid. Practising the full race-day nutrition strategy, product type, timing, and quantity, during training reduces the risk of gastrointestinal issues on competition day.

The Australian Institute of Sport publishes swimmer-specific guidance, Sports Dietitians Australia offers accredited practitioner support, and Sports Medicine Australia covers injury or health concerns.

How Do You Build a Swimming Nutrition Plan?

An effective swimming nutrition plan matches carbohydrate intake to training load, builds consistent hydration habits into every session, and prioritises the recovery window, particularly for double-session training days. Starting with the area that currently has the least consistency, whether that is pre-session fuelling, intra-session hydration, or post-session recovery, and building one element at a time makes the plan easier to evaluate and sustain. Science in Sport products across the energy, hydration, and recovery ranges are formulated for competitive athletes, produced to Informed Sport certification standards, and designed to integrate with both training and competition schedules. The Science in Sport blog offers further event-specific and session-specific guidance, and the Science in Sport customer team is available for product and programme questions.

Start Fuelling Your Swimming with Science in Sport

Science in Sport offers evidence-based products formulated for endurance and competitive athletes, produced to Informed Sport certification standards, and designed to support training, competition, and recovery. Find the right product combination for your swimming programme.

• Browse energy gels, chews, bars and powders
• Explore hydration products
• Shop the recovery range
• Read the fuelling guides
• Contact the team

Frequently Asked Questions

1. What should swimmers eat before training?

A carbohydrate-based meal two to three hours before training supports glycogen stores without digestive discomfort during the session. For early morning training, a smaller snack, such as fruit, toast, or a carbohydrate gel, eaten 30–60 minutes before is an effective alternative. High-fat and high-fibre foods close to a session should be avoided, as they slow digestion and increase the risk of gastrointestinal discomfort in the water.

2. Do swimmers need to drink during training?

Yes. Swimmers lose fluid through sweat even when fully immersed, and water immersion reduces thirst perception, making it easier to accumulate a fluid deficit without noticing. Sweat rates of 0.4 to more than 1.5 litres per hour have been recorded depending on pool temperature and session intensity. Keeping a drink bottle at the end of the lane and sipping between sets is the most practical strategy for maintaining hydration throughout a long session.

3. How do you fuel during a swim competition day?

Arrive with full glycogen stores supported by carbohydrate-rich meals the day before and on the morning of competition. Building a fuelling strategy ahead of the event ensures carbohydrate intake is planned across heats and finals rather than improvised on the day. Water and electrolyte products throughout the day support performance across multiple events and help replace fluid and sodium lost through sweat between races.

4. Are energy gels suitable for swimmers?

Yes, for sessions exceeding 60–75 minutes and for competition days with multiple events. Energy gels are compact, easy to take poolside or between heats, and deliver fast-acting carbohydrates without requiring preparation. Science in Sport energy gels are batch-tested through the Informed Sport programme. Each gel should be followed with water to support absorption.

5. What are the best electrolyte products for swimmers?

For sessions lasting more than 60 minutes, or in heated indoor pools where sweat rates are higher, electrolyte replacement helps maintain plasma volume and supports fluid retention. Hydro tablets dissolve in water for a convenient poolside drink, while electrolyte powders provide a flavoured alternative and may contribute a small amount of carbohydrate alongside sodium replacement. Both product types are certified through the Informed Sport programme.

6. How should swimmers recover after a session?

Begin within 30–60 minutes of finishing, combining carbohydrate to replenish glycogen with 20–25g of protein for muscle repair, consistent with AIS guidance for competitive athletes. When whole food is not immediately available, the Science in Sport recovery range provides carbohydrate, protein, and electrolytes in one serving, batch-tested through Informed Sport to remove banned-substance risk.