Hydration Plan for Long Endurance Sessions
Past the one-hour mark, water alone stops covering it. Here is how to plan fluid, sodium and carbohydrate before, during and after a long session, and where a hydration mix fits.
For a session over an hour, start hydrated, drink on a schedule while you work, and replace what you lost afterwards. Past 60 minutes, sodium and carbohydrate matter alongside fluid. The exact amounts depend on your sweat, so the hydration plan below shows you how to measure yours and build from there.
Over an hour changes the plan.
A 45-minute session is easy to cover. Drink to thirst, have water on hand, move on. A two-hour run, a long ride or a double practice is different. You lose more fluid, you lose more sodium, and the fuel in your system runs down.
The American College of Sports Medicine (ACSM) position stand on exercise and fluid replacement says the goal of drinking during exercise is to avoid losing more than about 2% of body weight to water. It also recommends adding carbohydrate and electrolytes to fluids for events longer than an hour. And because sweat rates and sweat sodium vary so much between people, it recommends customized plans.
How to read that: it is a guideline built on averages. It doesn't tell you your number. You find that in training.
Start the session hydrated.
You can't catch up on the move. Start from a good place.
- Drink in the hours before. The ACSM stand suggests about 5 to 7 mL per kg of body weight at least four hours before exercise. For a 70 kg athlete (about 154 lb), that is 350 to 490 mL.
- Check your urine. Pale straw colour is a reasonable sign. Dark means drink more.
- Eat normally. Food brings sodium and fluid with it. A salty breakfast is not a mistake before a long session.
- Top up close to the start. A small drink in the last 15 to 30 minutes is fine. Don't force down a litre at the start line.
Fluid, sodium and carbohydrate on a schedule.
Don't wait for a feeling. Set a plan, and use your own sweat rate to size it.
Find your sweat rate
Weigh yourself before and after a typical long session, in minimal clothing. Note what you drank. Then work it out:
72.0 kg on the scale.
71.0 kg. You drank 0.5 L and didn't use the bathroom.
1 kg is about 1 L, plus the 0.5 L you drank: 1.5 L in 90 minutes, or about 1 L an hour.
Drink enough to stay close to your starting weight, without gaining weight during the session. Losing more than 2% (1.4 kg for a 70 kg athlete) is the line the ACSM warns about.
Repeat in cool weather and in heat. Your number will change.
Add sodium
The same ACSM stand recommends including sodium, 0.5 to 0.7 g per litre of fluid, in what you drink during exercise lasting longer than an hour. It says this may help palatability and fluid retention, and may help in people who drink a lot of fluid. That is a general range. Heavy, salty sweaters may need more. Light sweaters may need less.
Add carbohydrate
For events longer than an hour, the ACSM stand points to carbohydrate in the range of 30 to 60 g an hour. It can come from a drink, a gel, chews or real food. Practise it. Your gut gets better at handling it with repetition.
Fluid, sodium and carbohydrate are three separate jobs. A drink can cover one, two or all three. Read the label so you know which jobs yours is doing.
Replace what the session took.
The ACSM goal after exercise is to replace the fluid and electrolyte deficit. Your post-session weigh-in tells you how big it is.
- Weigh in. Every kilogram lost is about a litre of sweat.
- Drink more than you lost. Some of what you drink leaves as urine, so the ACSM stand suggests about 1.5 L per kg lost when the next session is soon.
- Add sodium and food. Sodium helps you hold on to the fluid you drink. A meal does the job, or a drink with electrolytes alongside it.
- Add protein and carbohydrate. Recovery isn't only about fluid. See our guide to recovering between two sessions in one day.
You don't need to chug it all at once. Spread it over a few hours.
Where Hydration Mix fits.
If you use Hydration Mix, it goes in the bottle you are already planning, in the "during" and "after" parts of this plan. Here is how to use any electrolyte mix well:
Your pack's directions tell you the serving size and how much water to mix with it. Follow them. Then check the label for sodium and carbohydrate so you know what each bottle covers.
A bottle of mixed Hydration Mix counts toward your hourly fluid target. It doesn't add to it.
If the label shows little carbohydrate, add gels, chews or food to reach your hourly target.
Hydration MAX
Hydration MAX is the higher-sodium option in our range, for when a session calls for more. Its label sets limits, and they apply every time:
- One serving a day.
- Not for those under 14.
- Not to be taken with other magnesium or potassium supplements the same day.
Read the full label and follow it before you use it.
Most of our products are NSF Certified for Sport, which means tested by a third party for banned substances and purity. Check the page of the product you choose for its own status, and read what NSF Certified for Sport means.
Build your hydration plan for long endurance sessions.
Race day is not the day to try a new mix, a new gel or a new bottle schedule. Use your long sessions as rehearsals.
- Run the sweat test in one hard session and one easy one.
- Set a drinking reminder, every 15 to 20 minutes.
- Note stomach comfort, cramping and how you feel in the last 30 minutes.
- Adjust one thing at a time.
For daily fluid habits outside training, see how much water athletes should drink every day.
Hydration for long sessions: FAQ.
How much water does one serving of Hydration Mix make?
Follow the directions printed on your pack for the serving size and the amount of water to mix it with. That amount sets the sodium and carbohydrate concentration of your drink, so don't change it by guesswork.
How much should I drink per hour?
It depends on your sweat rate. The weigh-in test above gives you your number. Aim to stay within about 2% of your starting weight, as the ACSM stand advises, and don't gain weight during the session.
Do I need electrolytes for a 60 minute session?
Often not. The ACSM recommends adding sodium for exercise beyond an hour. In heat, or if you sweat heavily or see salt marks on your kit, you may want it sooner.
Can I drink too much water?
Yes. The 2015 international consensus statement on exercise-associated hyponatremia describes a serious form of low blood sodium caused by sustained overdrinking. That is why the plan is built on your measured sweat loss, not on drinking as much as possible. If you feel unwell during or after a long session, seek medical help.
What does NSF Certified for Sport mean?
It means a third party, NSF, has tested a product for banned substances and purity. Many leagues require it. Most of our products carry it, so check the page of the product you are choosing.
Plan it, test it, repeat it.
Start hydrated. Drink to a schedule built on your sweat rate. Add sodium past the hour mark. Replace the deficit afterwards. Then adjust in training, one change at a time.
See how much Hydration Mix per workoutReferences & further reading
Sawka et al., 2007. American College of Sports Medicine position stand: Exercise and fluid replacement. A position statement based on a review of the literature. It gives general guidance built on averages for fluids, sodium and carbohydrate, and covers no BioSteel product.
Hew-Butler et al., 2015. Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015 (Clinical Journal of Sport Medicine). An expert consensus statement, not a single trial. It describes the condition and its link to overdrinking, and says nothing about any BioSteel product.
Disclaimer: This article is for general education and is not medical advice. Talk to a qualified professional about your own needs.
