What hydration and nutrition are needed during long outings?

Long runs are a bit like a rite of passage, a stepping stone from casual runner to more experienced runner, preparing you for longer distances, from a half-marathon to a marathon or beyond, whether on the road or trail. A long run is one that lasts more than an hour, ideally an hour and a half or several hours. Like any prolonged physical effort, these runs can't be improvised, especially when it comes to hydration and nutrition. If you don't bring and consume the necessary fuel to power your engine (your body), you won't be able to complete your long run in good condition. A hydration or nutrition mistake on a short run won't have the same consequences as on a long one. The longer the run, the more the mistake will ultimately cost you. So, what are the key tips for properly hydrating and fueling yourself during a long run?

The right equipment to provide hydration and nutrition

First, you need to make sure you're properly equipped so you can carry the drinks, gels, bars, and other snacks necessary to stay hydrated and fueled regularly during your long run. A hydration or trail running backpack is one option. To have everything within easy and quick reach, another solution is to wear running or trail running shorts or tights with multiple pockets, such as the EDELI shorts with six pockets . 

Hydration is the keystone of any successful long outing.

Our bodies are composed of 60-70% fluids, and fluid intake must be regular because our bodies are constantly losing or consuming them every day. Especially during physical exercise like running, three-quarters of the energy we expend is transformed into heat. The body will try to cool itself down to stay within a safe core temperature range of approximately 37-38°C. This is the role of perspiration: to regulate our body temperature. And perspiring, of course, means consuming and losing fluids from our bodies. If we don't drink enough during prolonged exertion, we risk dehydration through perspiration, and if we become too dehydrated, we will inevitably experience a drop in performance and may potentially suffer from cramps.

An average hydration level that is both necessary and absorbable by the body during physical exercise is approximately 0.4 to 0.8 liters of fluid per hour of activity – a maximum of 1 L/h if tolerated. This value can fluctuate considerably depending on age, weight, intensity of the activity, and external conditions (temperature, relative humidity, sun, wind, etc.). Note: in some cases (smaller build, low intensity, and cold weather), 1 L/h will be far too much, and in other cases (larger build, high intensity, high heat), 0.5 L/h will be significantly insufficient. The classic indicators for proper dosage are urine color (fairly light but not transparent), no excessive thirst, and not losing more than 2 to 3% of body weight during the activity (less than 1.5-2 kg for 60 kg and less than 2-2.5 kg for 80 kg). These are general guidelines. The goal is, of course, to be within this range and ideally below the maximum weight loss.

Hydration should be regular and in small amounts every 10-15 minutes. It is also important to drink after your outing. Depending on the external conditions, the intensity, and the duration of your outing, you may have accumulated a water deficit that will need to be replenished afterward.

Be aware of dehydration symptoms such as cramps, headaches, dry mouth, or an abnormally high heart rate. If you experience one or more of these symptoms, it is wise to stop and rehydrate quickly.

When we lose fluids, especially through perspiration, we lose electrolytes, including sodium. It is therefore recommended to maintain a sodium intake of approximately 500 to 1000 mg/L, averaging around 700 mg of sodium per liter. Note that the concentration of sodium in perspiration can vary considerably from person to person: some lose little sodium (300-500 mg/L) and others much more (1000-1500 mg/L). White stains on clothing are a good indicator of relatively high sodium loss. Sodium and other electrolyte intake can be achieved through alternating between water and electrolyte drinks, or by consuming gels or salt bars just before or during a long run.

Finally, beware of the opposite extreme: drinking too much. This can cause digestive problems or vomiting. The real danger, although quite rare, is drinking a lot of water without sodium and having a blood sodium level that is too low. This is a particular risk during marathons, long trail runs, in hot weather, and with frequent aid stations.

Nutrition or long-term fuel

The other key aspect of a long run is nutrition in addition to hydration. For pre-run nutrition (between one and four hours before the run), avoid meals too high in fiber, fat, and protein to prevent digestive discomfort. Then, during the run, it's recommended to consume between 30 and 60 grams of carbohydrates per hour. For runs exceeding two or three hours, it's advisable to consume a quantity of carbohydrates closer to the upper end of this range, especially for long or very long runs. Carbohydrate intake can come from energy gels, energy bars, or even bananas. The key is to try different nutrition options during your long runs and see what works best for you in terms of digestion. Don't try new foods on the day of your race, whether it's a marathon or a long trail run.

Be careful to choose foods that are easy to chew and digest. During (very) long runs, simple functions like chewing and digesting can become increasingly difficult. Make things easier for yourself and select easy-to-chew bars. I even recommend pre-opening the wrappers of energy bars, for example, before your long run so you can easily take them out and eat them while running.

Finally, be careful to vary the sweet and savory flavors. Too much sweetness can quickly become cloying or make it difficult to consume another sweet gel.

To summarize, depending on the duration of the long outings:

< 1H30: drink 400-800 ml/h (potentially with electrolyte supplementation) and consume at least 20-30 g/h of carbohydrates

1h30 to 2h30: drink 400-800 ml/h alternating water and electrolyte drinks (including sodium) and carbohydrate intake of at least 40-60 g/h

> 3h: 400-800 ml/h alternating water and electrolyte drinks (including sodium) and carbohydrate intake of at least 60 g/h + gels or salt bars

Proper preparation beforehand, appropriate equipment, and tried-and-tested hydration and nutrition solutions are the recipe for successful long runs. And successful long runs are like small or large dress rehearsals that will allow you to fully enjoy your race on the big day.