A triathlete doesn't swim, bike and run in the same session every time. Most of your preparation happens in separate sessions, each with its own hydration needs.
This guide doesn't compare brands against each other. We already did that in our comparison of the best electrolyte drinks for triathletes.
Here, we look at how to hydrate during your training weeks, session by session, long before the day you put all three disciplines together.
Why training is managed differently than racing
A sprint or Olympic triathlon lasts 1 to 2.5 hours on race day. Your typical training week is split into separate sessions instead.
- Swimming: 2 to 3 sessions
- Cycling: 2 to 3 sessions
- Running: 2 to 3 sessions
- Brick: sometimes one session of cycling followed by running
Each type of session has its own hydration constraints, which differ from those of the race itself.
Key Takeaway
According to the ACSM, aim for 30 to 60 g of carbohydrates per hour once a session goes past 60 minutes. Go up to 90 g per hour beyond 2.5 hours.
Sodium falls between 300 and 600 mg per hour for sessions longer than 2 hours. Your long training rides often land squarely in these zones.
Your typical training week, session by session
Cycling is the discipline where you drink during the effort from 60 minutes on. Swimming is managed before and after the session.
| Session Type | Typical Duration | Need during the session |
|---|---|---|
| Swimming | 45 to 75 min | None during, hydrate before and after |
| Cycling | 45 min to 3h+ | Carbs and sodium starting at 60 min |
| Running | 30 to 90 min | Same as a standalone run |
| Brick (bike + run) | 60 to 120 min | Full test of your fuelling plan |
Your swimming sessions require hydration before and after
In the pool, you don't drink during a lap session, which usually lasts 45 to 75 minutes. Hydration is managed before you get in the water and right after, especially if you have another activity later that day.
Half a sachet to one sachet of Maple MC2 in the hour before a long session gives you a base of carbohydrates and sodium. You also avoid digestive discomfort once you're in the water.
In open water in the summer, the often cooler water masks part of your sweat loss. You may then underestimate your needs when you get out of the water if another session follows.
Your cycling sessions remain your main time for drinking
Your bike rides give you the most chances to drink during the effort, thanks to bottles and a steady pace. A training ride lasts from 45 minutes to over 3 hours depending on the phase of your plan and your target race format.
One sachet of Maple MC2 gives you 28 g of carbohydrates and 273 mg of sodium. You test and adjust your intake on these training rides, week after week, long before race day.
Maple MC2 Maple
$2.79 per sachet, $2.50 in a box of 12 ($29.99)
For whom: the triathlete who trains regularly and wants a simple base of carbohydrates and sodium for cycling and running sessions.
- 414 mg of electrolytes per sachet, made up of 273 mg of sodium, 94 mg of potassium and 47 mg of calcium
- 28 g of carbohydrates and 110 kcal, made from Quebec maple syrup
- To consider: for your longest sessions, you need several sachets per hour to approach the high end of the recommended carbohydrate range
Your running sessions
Your run sessions in triathlon preparation follow the same logic as a standalone running plan.
- Easy runs of 30 to 50 minutes: water is usually enough.
- Long runs or quality sessions: carbohydrates and sodium become useful after 60 minutes.
The brick session puts your fuelling plan to the test
The brick, a bike ride followed directly by a run, is the session that most closely resembles a race. It's the best time to test your full drinking plan.
Your stomach reacts differently when you run after drinking on the bike. The two situations don't feel the same to your digestive system.
So never test a new product on a standalone run and assume it will carry over after a bike ride.
Are you a heavy sweater? A simple test to find out
As with standalone running, the most reliable test is a simple one.
- Weigh yourself before and after a bike ride or run of at least 60 minutes.
- Don't drink during the session, or write down exactly what you drink.
- Count each kilo lost as about 1 litre of sweat.
A loss of more than 1 to 1.5% of your body weight signals high sweat loss for that length of effort. In that case, aim for the high end of the recommended ranges during your longest sessions.
How to know if your fuelling plan is working
Three signs show that your approach is on track.
- End of session: you finish your long rides and brick sessions without a marked energy drop in the final minutes.
- Transition: your switch from bike to run happens without digestive discomfort.
- Recovery: you recover well between two sessions close together in the same week.
Other signals need fixing during preparation, before you discover them on race day.
- A consistent slump at the end of a brick
- Stomach cramps from the first strides after the bike
- Repeatedly dark urine after your longest sessions
Busy weeks or training camp, two sessions per day
Some weeks include two sessions on the same day, for example a morning swim and an evening ride. Your recovery between the two then becomes as important as your intake during each session.
Have an electrolyte sachet between your two sessions, with a light meal, to start the second one with a proper base. Avoid showing up to your evening session still partly dehydrated from the morning, a common trap during heavy weeks.
Equipment for carrying your drink during training
- On the bike: one or two bottle cages on the frame are enough for most training rides.
- On the run: a hydration belt becomes useful on long runs if you train far from a water source.
- At the pool: mix your sachet in a bottle and keep it near your bag, to drink before and after.
Solid nutrition around your sessions
Before a long ride or a brick, eat a meal rich in carbohydrates and low in fibre 2 to 3 hours before. It fills your reserves without weighing on your stomach once you're moving.
After the session, a meal combining carbohydrates and protein within the hour supports your muscle recovery between two disciplines. Have it in addition to your electrolyte sachet.
On rides longer than 2 hours, some triathletes add easy-to-digest solid foods, such as bars or dried fruit. They reach the high end of the recommended carbohydrate range this way without drinking an excessive amount of fluid.
Planning your week according to your schedule
A triathlon preparation week often combines two types of sessions.
- Weekdays: short swim or run sessions, in the morning or evening.
- Weekends: longer bike or brick sessions.
Prepare your intake the night before for morning sessions, especially those before work. You won't have to improvise when you're short on time.
If two demanding sessions fall close together, such as a long Saturday ride and a Sunday run, take care of your recovery in between. It matters as much as your intake during each session.
Base phase vs. specific phase in triathlon
- Base phase: your sessions stay shorter and easier, so a light intake is enough for most of them.
- Specific phase: as your race approaches, your rides and brick sessions get longer and closer to your target pace. Your energy expenditure goes up for the same duration.
Adjust your intake upward as the intensity of your sessions increases toward the end of your preparation.
How to structure your intake over a complete training week
A typical triathlon preparation week combines several sessions in different disciplines. Keep a consistent hydration routine all week long, including on your shorter sessions.
This keeps up the quality of each session. It also prevents fatigue from building up because of poor recovery between workouts.
Adjusting the concentration of your drink according to the temperature
- In hot weather: a more diluted drink often goes down easier and encourages you to drink more, which partly makes up for the lower concentration.
- In cool weather: a normal or slightly higher concentration works, because you naturally drink less.
Test both approaches during your training sessions and adjust your concentration with the season.
Treat each discipline separately
- Swimming is prepared before.
- Cycling is managed during.
- Running follows the logic of a classic running plan.
The brick remains the only time you confirm that these three approaches work together, in the order and conditions of a race.
Once you've tested this plan several times in training, you have no surprises to manage on race day.
Practicing your transitions during training
The brick also lets you practice your transitions. You move from bike to run quickly, without losing your drinking rhythm.
Store your sachet or flask in the same spot every time, so you don't have to think about it mid-transition. A smooth transition in training reduces your stress on race day and keeps you from forgetting to drink.
Common mistakes in triathlon preparation
- Testing your fuelling plan on race day without having validated it in a brick session
- Neglecting hydration around your swims because you don't drink during the session
- Switching products between training and the race, which increases the risk of digestive discomfort
- Keeping the same intake from the start to the end of preparation, without adjusting it as sessions get longer
Want to compare brands for your race format? Our comparison of the 7 best electrolyte drinks for triathletes covers each option.
To see how your needs change with your running training distance, check out our guide by distance.
Frequently asked questions
