Preparing for a marathon, the legendary 42.195-kilometer race, is no longer limited to accumulating training mileage or choosing a pair of carbon-plated shoes. A major paradigm shift is taking place in the running world, driven by unprecedented environmental imperatives and regulatory changes. The era when runners could rely on the mass distribution of plastic water bottles every five kilometers is over. This transformation requires each participant to completely rethink their hydration self-sufficiency and the accessories needed to maintain performance throughout the effort.
An analysis of current trends and legislative frameworks shows that water management has become the central pillar of race strategy. Even mild dehydration, corresponding to a loss of just 2% of body weight, can drastically impair physical abilities, increasing heart rate and reducing muscle efficiency. In this context, the choice of hydration accessories is no longer a matter of comfort, but a logistical necessity imposed by race organizers, who are now banning disposable containers.
The regulatory context: The end of the disposable era in mass-participation sports
French legislation, particularly through the implementing decrees of the law on combating waste and promoting the circular economy, has set strict deadlines for sporting events. Since January 1, 2025, the ban on single-use plastic cups at mass events has been in force. This measure is the culmination of a gradual reduction in the permitted plastic content of containers, with the aim of almost completely eliminating it by the end of 2026.
The Paris Marathon, one of the largest in the world, is serving as a testing ground for these new practices. From 2024 onward, plastic bottles began disappearing from aid stations, temporarily replaced by cardboard, before a complete transition to systems with no disposable containers whatsoever planned for 2026. Runners are now encouraged to keep, refill, and reuse their own accessories. This development is transforming the marathon, traditionally supported, into a semi-self-sufficient event in which mastery of carrying equipment has become as crucial as top speed.
Logistical impacts for marathon runners
This transition requires athletes to equip themselves with reusable containers that can be refilled quickly at fountains or water stations set up by organizers. The foldable eco cup, once reserved for trail runners, is becoming a standard accessory on the road. Likewise, carrying personal supplies in soft flasks or hydration belts helps avoid the often chaotic crowds at aid stations, allowing for smoother, less stressful pace management.
Exercise physiology and hydration needs: understanding the mechanisms of thirst
Hydration during a marathon is not only about comfort, but also about complex biological needs. During endurance exercise, the muscles produce intense heat. To maintain a stable body temperature, the body uses sweating as its primary cooling mechanism. This water loss is accompanied by the loss of essential minerals, or electrolytes, including sodium, potassium, and magnesium.
The amount of water needed varies according to the runner's profile, pace, weight, sweat rate, and weather conditions. Standard recommendations suggest consuming 100 to 200 ml every 15 to 20 minutes. However, drinking excessively large amounts of water can be dangerous, as it dilutes the sodium in the blood, potentially causing hyponatremia, a potentially serious condition. It is therefore essential to combine water with mineral and carbohydrate intake through sports drinks, gels, or energy compotes.
Dehydration indicators and how to manage them
Signs of dehydration often include reduced alertness, cramps, headaches, and an abnormally elevated heart rate at the same running pace. To avoid these inconveniences, using graduated or transparent containers, such as silicone bottles, allows you to monitor your intake precisely in real time. The goal is to compensate for losses without overloading the stomach, which requires ergonomic equipment that allows you to drink small, frequent sips rather than large amounts at spaced intervals.
| Parameter | Impact of optimal hydration | Risk of dehydration |
| Thermoregulation | Effective, maintaining the pace | Overheating, reduced performance |
| Heart rate | Stable | Compensatory increase (cardiac drift) |
| Digestion | Facilitated by a regular intake | Slowing down, gastrointestinal issues |
| Recovery | Faster recovery after exercise | Prolonged muscle soreness |
Types of hydration accessories: choosing your carrying system
The market offers a variety of solutions for carrying water and energy gels, each suited to specific needs depending on the target time and the runner's experience.
The hydration belt: lightweight and accessible
The belt is often preferred for its minimalism. It can carry one or two 250ml to 500ml soft flasks as well as the necessary nutrition. For an urban marathon, it offers the advantage of not restricting chest breathing, unlike some overly tight backpacks. Modern models, such as "Flipbelt"-style compression belts, hold accessories close to the body, thereby eliminating the unpleasant sloshing of water.
The hydration vest or backpack: total autonomy
The vest has become the go-to choice for marathon runners seeking more than 1.5 hours of autonomy without access to aid stations. With a capacity of 2 to 5 liters, it can carry two 500ml soft flasks at the front and, if needed, a hydration bladder at the back. The vests are ergonomically designed to distribute weight across the shoulders and back, minimizing muscle fatigue. This is the ideal solution for those who prefer to keep their hands free and access their gels and accessories without stopping. However, repeated rubbing can cause chafing over time.
Hand carrying: for short distances or as a supplement
This consists of a small soft flask secured to the hand with a strap. Very popular in the United States, this solution is appealing to runners who want to have water constantly available without wearing a belt or backpack. However, over marathon distance, the asymmetrical weight can create tension in the shoulder and arm.
Focus on the Mulebar range: the combination of silicone and sustainable performance
In this context of ecological transition, the Mulebar brand has stood out by developing a range of food-grade silicone accessories designed to last and meet the demands of high-level competition. Unlike traditional plastic (TPU), silicone offers absolute neutrality of taste and greater resistance to repeated washing.
The 60ml silicone flask: the nutrition revolution
One of the marathon runner's biggest logistical challenges is managing energy gels. Disposable packaging is often difficult to open when fatigued, sticks to the fingers, and too often ends up on the ground. The Mulebar 60ml flask offers a practical solution to these issues.
-
Capacity and use: It can hold the equivalent of two standard gel tubes. Its compact design allows it to slip into a shorts pocket or waistband.
-
Mechanism: Equipped with a drip-proof valve, it allows you to consume your gel in several installments and in small squeezes. The cap can be operated with one hand, which is crucial for maintaining your pace.
-
Care: Fully washable, it is the perfect accessory for those who buy their gel in eco-refills, reducing plastic waste by more than 90%.
The 150ml soft flask: the strategic intermediate size
For runners who need a higher carbohydrate intake or want to carry a homemade mixture, the 150ml flask is an ideal compromise.
-
Optimization: It can hold up to 8 gel servings, covering the nutritional needs of an entire marathon.
-
Comfort: Its flexibility allows it to be emptied gradually without creating an airlock. It fits easily into the front pockets of a hydration vest or on the side of a belt.
The 500ml soft flask: the foundation of hydration autonomy
The 500ml soft flask is the central component of a modern hydration system.
-
Innovation: The Mulebar version stands out with a wide opening that makes filling easier, particularly when adding sports drink powders such as electrolytes or isotonic drinks.
-
Ergonomics: It features a high-performance valve that prevents leaks, even under pressure in a fully loaded pack. Its transparency allows an immediate visual check of the remaining liquid level.
-
Versatility: Suitable for both trail and road running, it collapses completely when empty, taking up no unnecessary space.
The 20cl collapsible eco-cup: the regulatory all-rounder
Now mandatory in almost all official races to eliminate disposable cups, the Mulebar eco-cup is an eco-friendly safety accessory.
-
Design: Its silicone structure allows it to be folded flat. It can be attached to a bag via a ring or slipped into a belt.
-
Use: It allows you to drink at refreshment fountains without generating waste. Weighing just 8 g, it is completely imperceptible during the race.
Comparative analysis: materials and durability
The choice between silicone and TPU (thermoplastic polyurethane) is a major selection criterion for athletes concerned about their health and the environment.
| Criterion | Silicone | TPU |
| Taste of the water | Neutral, no flavour transfer | May have a plastic taste |
| Heat resistance | Very high, dishwasher-safe | Limited, may deform in heat |
| Flexibility | Excellent, does not retain creases | Good, but may become brittle |
| Hygiene | Naturally antibacterial, easy to disinfect | Requires very thorough drying |
| Composition |
BPA- and phthalate-free |
Often BPA-free, but more chemical |
Food-grade silicone is an inert material that does not react with acidic drinks or energy powders, ensuring the purity of the contents, which is essential during an effort lasting several hours.
Fuelling strategy: the link between hydration and nutrition
Hydration cannot be separated from solid or semi-liquid nutrition. A marathon is won as much in the kitchen as on the track. The strategy must be tested several times during long training runs to accustom the digestive system. The famous Gut Training.
Energy gel intake
It is recommended to plan for three types of gels to cover the 42 km: long-lasting energy gels for kilometres 5, 15 and 25, an antioxidant gel halfway through the race to combat oxidative stress, and caffeine-based “boost” gels for the final 10 kilometres. Using Mulebar flasks makes it possible to prepare these doses in advance and consume them without having to deal with soiled packaging. For more details on choosing your intake, you can consult our guide to energy gels for the marathon.
The isotonic sports drink
For efforts lasting more than an hour, water alone can lead to a drop in performance. An isotonic drink, whose osmolality is close to that of blood plasma, allows ultra-fast absorption without weighing on the stomach. It provides the carbohydrates needed to maintain glycogen levels and the minerals needed to replace those lost through sweating. Mulebar offers powdered energy drinks specifically formulated to be diluted in our 500ml soft flasks.
Managing salt and electrolytes
In hot weather, sodium loss can reach 1 gram per hour. If this salt is not replaced, the risk of cramps and exhaustion increases. Using electrolyte tablets or enriched powders is a winning strategy, particularly if you tend to have white salt marks on your clothes after exercise. To learn more about this topic, discover our article on natural electrolytes.
Maintenance and hygiene: making your accessories last
Investing in quality accessories requires minimal maintenance to ensure food safety and extend the equipment’s lifespan.
Daily cleaning and storage
After each use, it is essential to rinse the soft flasks and bottles with clean water, especially if they contained sugary drinks. Sugar creates favorable conditions for mold growth. Silicone has the advantage of being dishwasher-safe, ensuring effective thermal disinfection.
Tips for perfect drying
The number-one enemy of soft containers is residual moisture during storage.
-
Drying rack: We recommend using a bottle drying rack or hanging the soft flasks upside down with the cap open.
-
Freezer tip: To prevent bacterial growth between outings, some runners store their clean, empty hydration bladders and soft flasks directly in the freezer.
Valve maintenance
The “bite-valve” valves (which you pinch with your teeth) can become clogged. They are generally removable. Occasional soaking in a mixture of warm water and baking soda helps remove deposits and any lingering energy drink odors.
The modern marathon is no longer just a race against the clock; it is also a commitment to more sustainable sports practices. The end of disposable water bottles marks the beginning of a new era in which logistical efficiency takes priority. By choosing high-performance, durable, and ergonomic accessories, every runner can manage their energy optimally while complying with the new environmental requirements.
Answers to frequently asked questions
What is the essential accessory for a first marathon?
Besides a good pair of shoes, the essential accessory is a hydration-carrying system (belt or vest) that has already been tested during training. With the new environmental standards, having your own 500 ml soft flask and an eco-cup is now mandatory at many races to access the water stations.
How can you carry water without a backpack?
There are several alternatives to avoid using a backpack:
- Hydration belt: It allows you to carry up to 1 liter divided between two flasks.
- Technical running shorts: Some models have integrated “belt” pockets made of stretchy mesh that can hold a 250 ml flask and gels.
- Handheld bottle holder: A minimalist solution for runners who cannot stand carrying anything around their waist.
How much liquid do I need?
The average need is 500 ml to 800 ml per hour of exertion. For a 4-hour marathon, that represents approximately 2 to 3 liters. Since carrying 3 kg of water is counterproductive, the ideal strategy is to start with 1 liter (two 500 ml flasks) and refill them at the aid stations using the water ramps provided by the organizers.
Can hot drinks be put in silicone flasks?
Yes, one of silicone’s major advantages is its thermal resistance. Unlike TPU, which can release substances or deform, silicone can hold hot drinks (tea, herbal tea) for winter training sessions, or be placed in the freezer to keep water cool for longer in summer.
Why are plastic bottles banned at marathons?
The ban aims to reduce the carbon footprint and massive plastic pollution generated by sporting events. A marathon with 50,000 participants can generate more than 250,000 disposable bottles and cups in just a few hours. Regulations such as France’s AGEC law now require a transition to reusable products to preserve urban and natural spaces.
