Training in UAE Heat 2026: Hydration, Electrolytes and Sweat Loss

For half the year, training in the UAE means training in heat that most sports science was never designed around. The usual advice, "drink plenty of water", is incomplete here. What you lose in sweat is water and salt, and how much of each varies a lot from one person to the next. The practical question is how to work out your own numbers instead of guessing.

This article mentions products we sell. We have tried to describe the evidence the same way we would if we did not.

What Happens When You Sweat in 40 Degrees

Sweat is how your body dumps heat. As it evaporates from your skin it cools you, and the hotter the room or the road, the more of it you produce. Sweat is mostly water, but it also carries sodium, plus smaller amounts of chloride, potassium and other minerals.

Two numbers decide what you need to replace:

• Sweat rate: how many litres you lose per hour.
• Sweat sodium: how salty that sweat is.

Both vary widely. A review of sweat-testing research lists exercise intensity, environmental conditions, heat acclimation, fitness, body size, sex, diet and hydration status as factors that shift them (Baker, 2017). That is why the American College of Sports Medicine recommends customised fluid plans rather than one figure for everyone (ACSM, 2007).

How Much People Actually Lose

The largest dataset comes from the Gatorade Sports Science Institute, which tested 1,303 athletes between 2000 and 2017 (Barnes, 2019). Average sweat rates ranged from about 0.8 litres an hour in baseball to about 1.5 litres an hour in American football, with endurance athletes close behind at about 1.3 litres an hour.

Sodium loss averaged between roughly 27 and 56 mmol an hour depending on the sport. That works out to about 620 to 1,290 mg of sodium an hour of training. The spread around those averages was wide, so some people lose a fraction of that and others lose far more.

These are averages from athletes, not a target. They show the scale: a long, hot session can cost well over a litre of fluid and a meaningful amount of salt.

When Dehydration Starts to Cost You

The ACSM position stand sets the goal of drinking during exercise as preventing a water deficit of more than 2% of body weight (ACSM, 2007). For a 75 kg person that is 1.5 kg.

A major review of the dehydration literature supports a threshold of about 2% for impaired endurance performance. For strength and power the picture is less clear: the impairment is marginal and no clear threshold has been shown (Cheuvront, 2014). In plain terms, a hot 10 km run suffers from dehydration more than a heavy set of squats does.

Why Plain Water Alone Can Dilute You

The opposite mistake is less known and more dangerous. If you drink much more water than you sweat out, the sodium in your blood becomes diluted. This is called exercise-associated hyponatraemia, and an international consensus statement identifies drinking in excess of losses as its main cause (Hew-Butler, 2015). Symptoms can look like dehydration: headache, nausea, confusion, bloating.

The risk is highest in long events where people drink at every opportunity "to stay ahead", and in slower participants who sweat less but keep drinking. The simple warning sign: if you weigh more after a session than before it, you drank too much.

How to Work Out Your Own Fluid Needs

Changes in body weight are the simplest and most accurate field method for measuring sweat rate (Baker, 2017). You need a bathroom scale and one honest session.

1. Weigh yourself before training, after using the toilet, in minimal clothing.
2. Note how much you drink during the session.
3. Towel off and weigh yourself again in the same minimal clothing. Sweat trapped in a soaked shirt makes the result look smaller than it is.
4. Sweat lost = weight before − weight after + fluid drunk. One kilogram is roughly one litre.
5. Divide by the session length in hours to get your sweat rate.

Do this a few times: indoors and outdoors, in July and in January. Your summer outdoor number is the one that matters most here.

Turning the number into a plan

• Aim to finish within 2% of your starting weight. You do not need to replace every drop during the session.
• Never finish heavier than you started. That means you drank more than you lost.
• Start hydrated. ACSM advises drinking normally with meals and, when needed, starting extra fluid several hours before training so you have time to pass the excess (ACSM, 2007).
• Replace the deficit afterwards over the next few hours, ideally with a meal. Salty food helps you hold on to the water you drink.

When Electrolytes Actually Matter

ACSM notes that drinks containing electrolytes and carbohydrate can offer benefits over water alone "under certain circumstances" (ACSM, 2007). Those circumstances are specific:

• Sessions longer than about an hour, especially outdoors.
• High sweat rates: you regularly lose more than 1 litre an hour on the scale test.
• Salty sweat: white salt marks on your cap or shirt after drying are a common sign.
• Back-to-back sessions or a full day outside, where you cannot rely on a meal in between.

For a 45-minute gym session in an air-conditioned room, water and a normal meal afterwards cover it. That is most people, most of the time.

What to check on an electrolyte label

Look for sodium per serving first. Many "hydration" products lead with potassium, magnesium and vitamins and carry little sodium, even though sodium is the main electrolyte lost in sweat. A drink with no sodium is a flavoured water, which is fine, but it will not replace salt. If you need carbohydrate as well for sessions past roughly 90 minutes, see our guide to cyclic dextrin for long sessions.

UAE Context

Three local factors change the picture.

• Humidity on the coast. In Dubai and Abu Dhabi summers, humid air slows the evaporation of sweat. You keep sweating, but less of it cools you, so losses climb while you still feel hot.
• The jump from indoor to outdoor. Many people train in air-conditioned gyms all summer, then play football or padel outside, or run at dawn. Your indoor sweat rate tells you little about an outdoor session.
• Heat acclimation. Your body adapts to heat over the first couple of weeks of regular exposure, and acclimation is one of the factors that changes sweat rate and saltiness (Baker, 2017). Someone back from a summer abroad is not acclimatised, so go easier for the first sessions.

Fasting changes the timing completely. If you train during Ramadan, our Ramadan electrolytes guide covers how to fit fluid and salt into the eating window.

The Hydration Drink We Stock

Applied Nutrition Amino Hydrate combines electrolytes and salts with BCAAs and citrulline, with zero sugar. It is halal certified and every batch is tested under Informed Sport. Check the label for the sodium per serving and compare it with your own sweat test.

Be clear about what it is. The electrolytes and the flavour are the useful part for long, hot sessions, because a drink you enjoy is a drink you actually take. If you already eat enough protein, the BCAAs add little for muscle. For an hour indoors, you do not need it.

What We Do Not Claim

We do not claim that any electrolyte drink improves performance on its own, prevents heat illness, or replaces common sense about when to train. Most gym sessions need water and a meal, nothing more. Electrolytes earn their place in long, hot, sweaty sessions. Heat exhaustion and heat stroke are medical emergencies: if you feel dizzy, confused or stop sweating in the heat, stop, get somewhere cool and get help. If you have high blood pressure, kidney or heart disease, or take medication that affects fluid or sodium, speak to your doctor before changing your salt or fluid intake.

Last updated October 2026 by the SupplMentor editorial team. This article is for general information and is not medical advice. If you have a medical condition or take medication, speak to a doctor before starting any new supplement.