What accessories for hydration during a marathon?

Preparing for a marathon, the legendary 42.195-kilometer race, is no longer simply a matter of racking up training kilometers or choosing a pair of carbon-plated shoes. A major paradigm shift is underway in the world of running, driven by environmental imperatives and unprecedented regulatory changes. The days when runners could rely on a massive distribution of plastic water bottles every five kilometers are over. This transformation requires each participant to completely rethink their hydration strategy and the accessories needed to maintain performance throughout the race.

Analysis of current trends and legislative frameworks shows that water management has become the central focus of race strategy. Even mild dehydration, corresponding to a loss of just 2% of body weight, can drastically impair physical performance, 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 now ban disposable containers.

The regulatory context: The end of the disposable era in mass participation sport

The French legislative framework, 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 gatherings has been in effect. This measure is the culmination of a gradual reduction in the permitted plastic content in containers, aiming for near-total elimination by the end of 2026.

The Paris Marathon, one of the world's largest, serves as a testing ground for these new practices. Starting in 2024, plastic bottles began disappearing from aid stations, temporarily replaced by cardboard, before a complete transition to devices with no disposable containers planned for 2026. Runners are now encouraged to keep, recharge and reuse their own accessories. This evolution transforms the marathon, traditionally assisted, into a semi-autonomous event where mastery of carrying equipment becomes as crucial as top speed.

Logistical impacts for the marathon runner

This transition requires athletes to equip themselves with reusable containers that can be quickly refilled at fountains or water ramps installed by the organizers. The collapsible eco-cup, once reserved for trail runners, is becoming a standard accessory on the road. Similarly, carrying personal supplies via soft flasks or hydration belts helps avoid the often chaotic crowds at aid stations, thus offering smoother and less stressful pace management.

Physiology of exercise and hydration needs: understanding the mechanisms of thirst

Hydration during a marathon isn't just about comfort; it addresses complex biological needs. During endurance exercise, 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 depletion of essential minerals, the electrolytes, including sodium, potassium, and magnesium.

The amount of water needed varies depending on the runner's profile, pace, weight, perspiration rate, and weather conditions. Standard recommendations suggest consuming 100 to 200 ml every 15 to 20 minutes. Drinking too much water can be dangerous, however, as it dilutes sodium in the blood, potentially leading to hyponatremia, a potentially serious condition. It is therefore imperative to combine water with mineral and carbohydrate intake via sports drinks, gels or energy compotes.

Dehydration indicators and their management

Signs of dehydration often include decreased mental clarity, cramps, headaches, and an abnormally high heart rate for the same running pace. To avoid these inconveniences, the use of graduated or transparent containers, such as silicone water bottles, allows you to precisely track your consumption in real time. The goal is to compensate for losses without overloading the stomach, which requires ergonomic equipment that allows drinking in small, frequent sips rather than large, spaced-out gulps.

Setting	Impact of optimal hydration	Risk of dehydration
Thermoregulation	Effective, maintains pace	Overheating, decreased performance
Heart rate	Stable	Compensatory increase (cardiac drift)
Digestion	Facilitated by a regular intake	Slowing of the stomach, gastric problems
Recovery	Faster after exertion	Prolonged muscle pain

Types of hydration accessories: choosing your carrying system

The market offers a variety of solutions for carrying water and energy gels, each adapted to specific needs depending on the target time and the runner's experience.

The hydration belt: lightweight and affordable

The belt is often preferred for its minimalism. It allows you to carry one or two flasks of 250ml to 500ml as well as the necessary nutrition. For an urban marathon, it offers the advantage of not hindering chest breathing, unlike some bags that are too tight. Modern designs, such as "Flipbelt" type compression belts, hold accessories against the body, thus eliminating the unpleasant sloshing of water.

The hydration vest or pack: towards total autonomy

The vest has become the standard for marathon runners seeking autonomy of more than 1 hour 30 minutes of running without refueling. With a volume of 2 to 5 liters, it allows you to carry two 500ml flasks on the front and, if needed, a water bladder on the back. The ergonomics of the vests are designed to distribute the weight across the shoulders and back, minimizing muscle fatigue. This is the ideal solution for those who prefer to have their hands free and access their gels and accessories without stopping. However, repeated rubbing can cause burns over time.

Carrying by hand: for short distances or as a supplement.

This consists of a small, flexible water bottle attached to the hand by a strap. Very popular in the United States, this solution is ideal for runners who want to have water readily available without wearing a belt or bag. However, over the marathon distance, asymmetrical weight distribution can generate tension in the shoulder and arm.

Focus on the Mulebar range: the combination of silicone and lasting performance

In this context of ecological transition, the Mulebar brand has distinguished itself 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 taste neutrality and increased resistance to repeated washing.

The 60ml silicone vial: the nutrition revolution

One of the biggest logistical challenges for marathon runners is managing energy gels. Disposable wrappers are often difficult to open when fatigued, stick to fingers, and too often end up on the ground. The 60ml Mulebar flask offers a practical solution to these problems.

• Capacity and use: It can hold the equivalent of two standard gel tubes. Its compact size allows it to be slipped into a shorts pocket or belt loop.

• Mechanism: Equipped with a drip-free valve, it allows you to consume the gel in several sips with 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, thus reducing plastic waste by more than 90%.

The 150ml soft flask: the strategic intermediate format

For runners needing a higher carbohydrate intake or wishing to carry a homemade mix, the 150ml flask is an ideal compromise.

• Optimization: It can hold up to 8 portions of gel, which covers all the needs of a full marathon.

• Comfort: Its flexibility allows it to be emptied gradually without creating a draft. It can be easily stored in the front pockets of a hydration vest or on the side of a belt.

The 500ml soft water bottle: the foundation of hydration autonomy

The 500ml soft flask is the central element of the modern hydration system.

• Innovation: The Mulebar version is distinguished by a wide opening which facilitates filling, especially when adding performance powders such as electrolytes or isotonic drinks.

• Ergonomics: It features a high-performance valve that prevents leaks, even under pressure in a full bag. Its transparency allows for immediate visual monitoring of the remaining liquid level.

• Versatility: Suitable for trail running as well as road running, it flattens completely when empty to avoid taking up unnecessary volume.

The 20cl collapsible eco-cup: the all-purpose regulatory solution

Having become mandatory on almost all official races to eliminate disposable cups, the Mulebar eco-cup is an ecological 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 from aid stations without generating waste. Its weight of only 8g makes it 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.

Food-grade silicone is an inert material that does not react with acidic drinks or energy powders, guaranteeing the purity of the contents, which is essential during exertion lasting several hours.

Supply 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 repeatedly during long training runs to accustom the digestive system. The famous Gut Training.

The intake of energy gels

It is recommended to plan three types of gels to cover the 42 km: long-lasting energy gels for kilometers 5, 15 and 25, an antioxidant gel for the mid-race to combat oxidative stress, and caffeine-based "boost" gels for the last 10 kilometers. The use of Mulebar vials allows these doses to be prepared in advance and consumed without having to deal with soiled packaging. For more details on choosing your contributions, you can consult our guide on the energy gels for the marathon.

Isotonic sports drink

For efforts lasting longer 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 for ultra-fast absorption without putting a strain on the stomach. It provides the carbohydrates needed to maintain glycogen levels and the minerals to compensate for sweat losses. Mulebar offers powdered energy drinks specifically formulated to be diluted in our 500ml flasks.

Salt and electrolyte management

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, especially if you tend to have white salt stains on your clothes after exercise. To delve deeper into this topic, check out our article on the natural electrolytes.

Maintenance and hygiene: making your accessories last

Investing in quality accessories requires minimal maintenance to ensure food safety and equipment longevity.

Daily cleaning and storage

After each use, it is essential to rinse flasks and bottles with clean water, especially if they have contained sugary drinks. Sugar creates a favorable environment for mold growth. Silicone has the advantage of being dishwasher safe, which ensures effective thermal disinfection.

Tips for perfect drying

The number one enemy of flexible containers is residual moisture during storage.

• Drying support: It is recommended to use a bottle drying rack or to hang the flasks upside down with the cap open.

• Freezer tip: To avoid bacterial growth between outings, some runners store their clean, empty water bladders and flasks directly in the freezer.

Valve maintenance

Bite valves (the kind you pinch with your teeth) can get clogged. They are usually removable. Occasionally soaking them 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 challenge against the clock; it's also a commitment to more sustainable sports practices. The end of disposable water bottles marks the beginning of a new era where logistical ingenuity reigns supreme. By choosing high-performance, durable, and ergonomic accessories, every runner ensures optimal energy management while respecting new environmental constraints.

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) already tested in training. With the new environmental standards, owning your own 500 ml soft flask and one eco-cup is now mandatory on many races to access water points.

How to carry water without a backpack?

There are several alternatives to avoid using a backpack:

• The hydration belt: It allows you to carry up to 1 liter distributed in two flasks.
• Technical running shorts: Some models have integrated "waistband" pockets made of stretch mesh that can hold a 250ml flask and gels.
• The hand-held bottle holder: A minimalist solution for runners who can't stand anything around their waist.

How much liquid do I need?

The average requirement is 500ml to 800ml per hour of exertion. For a 4-hour marathon, this represents approximately 2 to 3 liters. Since carrying 3kg of water is counterproductive, the ideal strategy is to start with 1 liter (two 500ml flasks) and refill them at aid stations using the water ramps provided by the organizers.

Can you put hot drinks in silicone flasks?

Yes, one of the major advantages of silicone is its thermal resistance. Unlike TPU, which can release substances or deform, silicone can hold hot drinks (tea, infusions) for winter workouts, or be placed in the freezer to keep water cold 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 the AGEC law in France now require a transition towards reusable materials to preserve urban and natural spaces.