Energy vs hydration: what your body actually needs

Energy and hydration are two different jobs. A gel's job is carbohydrate: 100 calories your muscles can use within minutes, plus a modest dose of sodium. Water's job is to keep blood volume, sweating and temperature control working. Fading or cramping late in a session often traces back to one of the two, and the fix depends on which. This guide separates them, puts numbers on each, and shows when a gel plus plain water is enough and when to add an electrolyte drink or capsules.

Energy vs hydration at a glance

	Energy	Hydration
Job	Carbohydrate for working muscles	Fluid and electrolyte balance
Key nutrient	Carbohydrate (maltodextrin and fructose in our gels)	Water, plus the sodium lost in sweat
When it matters most	Efforts beyond about an hour, and higher intensity	Every session; more so in heat, humidity and beyond an hour
What delivers it	Energy gels	Water, with an electrolyte drink or capsules when losses run high
What running short feels like	Fading pace, flat legs, fatigue	Heart rate climbing at the same pace, headache, effort feeling harder than it should, cramps

Why they are separate jobs

During exercise your muscles run largely on carbohydrate stored as glycogen. As those stores fall, fatigue sets in, and the only way to slow that is to put carbohydrate back in while you move. Many endurance athletes aim for 30–60 g of carbohydrate an hour; a gel every 30 minutes lands you mid-range, every 20 minutes takes you to the top of it.

At the same time you are sweating out fluid and electrolytes, mainly sodium. Lose too much and your heart has to work harder to push blood to the muscles, the effort feels harder than the pace justifies, and headaches and cramps follow. One product does not fix both. Carbohydrate needs water to be absorbed, and water on its own carries no energy. So the practical answer for nearly every endurance session is the same: gels for energy, water for hydration, and extra electrolytes only when sweat losses outrun what the gels supply.

What a gel gives you, and what it does not

All three of our gels carry 100 calories, a two-source carbohydrate blend and some sodium. The sodium helps, but it is a top-up, not a substitute for drinking.

Gel	Carbohydrate	Sodium	Hydration note
Original Energy Gel	21–23 g	60–125 mg	Take with a few sips of water
Liquid Energy Gel	24 g	75 mg	Contains some water, but not enough to count as a drink
Roctane Energy Gel	19–21 g	125–180 mg	Up to 3× the sodium of Original; Lemonade has the most of any flavour

Do the arithmetic for one hour. Two to three Original gels supply roughly 120–375 mg of sodium; two to three Roctane gels, roughly 250–540 mg. A heavy sweater can lose more than 1,000 mg of sodium in an hour, and more again when it is hot or humid. For a cool 90-minute run, the sodium in your gels may be enough; test it in training. For a four-hour ride in May it is not, and that gap is what electrolytes are for. A sensible starting point is 300–800 mg of sodium per hour, adjusted from there.

Always chase a gel with water. A few sips help the carbohydrate leave the stomach and reach the blood faster. This applies to Liquid Energy Gel too: it is drinkable, but you still need to keep drinking alongside it.

How much water per hour

The working range is 450–900 ml (16–30 oz) per hour of activity. Where you sit in that range depends on body size, how hard you are sweating and the weather, so treat it as a bracket to test in training rather than a number to hit on race day. Sip every 10–15 minutes instead of draining a bottle on the hour: small, frequent doses are easier on the stomach and keep delivery steady. In one study, athletes who drank to a schedule performed better than those who drank only when thirsty.

Two checks tell you whether you have the amount right. A sloshing stomach means you are drinking more than you can absorb, so back off. A heart rate that climbs at steady pace, a headache, or a calf that starts to twitch late in a long session points the other way.

When	How much	Why
1–2 hours before	200–350 ml (7–12 oz)	Start topped up without a full bladder on the start line
Marathon morning	About 1/10 of your body weight in pounds, as ounces, 4 hours before the gun (roughly 450 ml for a 70 kg runner)	Leaves time to pass any excess
During	450–900 ml (16–30 oz) per hour	Sip every 10–15 min; use aid stations so you carry less
The 2–3 days before a marathon	2–4 litres a day	Hydration starts well before race morning
After	Fluids with carbohydrate, protein and electrolytes, ideally within 30 minutes	Especially after hot sessions

When to add electrolytes

For short, cool sessions, plain water plus the sodium in your gels may be enough. Add an electrolyte drink or capsules when one of these is true:

• It is hot or humid. Heat and humidity raise both fluid and sodium losses. A humid coastal start in Mumbai or Chennai pushes sweat losses up even when the thermometer looks mild, and the dry heat of a Delhi or Hyderabad summer evaporates sweat before you notice how much you are losing.
• You will be out for more than an hour. Sodium losses add up over a long ride or trail run, and gels alone will not keep pace with someone losing 1,000 mg an hour.
• You cramp late in long efforts. Cramps have several causes, fatigue included, but dehydration and electrolyte imbalance are two of the usual suspects.

Heat tip: cold drinks, or a slushie, before and during a hot session help keep core temperature lower for longer. If your goal race is a hot one, 1–2 weeks of daily sessions of around 90 minutes in the heat builds most of the adaptation; the detail is in training and racing in the heat.

A simple plan by session

Session	Energy	Water	Electrolytes
Under 60 minutes	Optional: one gel 5 minutes before the start	Start well hydrated; drink as needed	Not needed in mild weather
60–90 minutes	One gel every 20–30 minutes once past the hour	450–900 ml per hour	Gel sodium may be enough if it is cool; test it
90 minutes to 2 hours	One gel every 20–30 minutes	450–900 ml per hour, sipped every 10–15 min	Add electrolytes, aiming for 300–800 mg sodium per hour
Over 2 hours	One gel every 20–30 minutes; Roctane if you want the extra sodium	Top of the range if sweating hard	Add an electrolyte drink or capsules
Hot or humid, any length	Keep fuelling as planned	Top of the range; cold fluids help	Add electrolytes

Rehearse the plan on long training days, gels, water and electrolytes together, so you know what your stomach accepts in race conditions. Train your gut covers how.

FAQ

Do I need both energy and hydration?

It depends on duration and conditions. Any session needs fluid. Once you are past about an hour you also need carbohydrate, so a gel every 20–30 minutes comes in. Past an hour, and especially in heat and humidity, add electrolytes on top of both.

Can I skip water if I use Liquid Energy Gel?

No. Liquid Energy Gel contains some water, which makes it easier to take, but nowhere near the 450–900 ml an hour you need. Keep drinking alongside it.

Is a cramp a sign I need salt?

Not necessarily. Cramps are linked to dehydration and electrolyte imbalance but also to muscle fatigue, poor pacing and under-conditioning. When one hits, slow down, stretch the muscle gently and sip fluid with electrolytes; drinking starts to affect blood plasma within about 15 minutes. If cramps keep landing in the same spot, look at training load and strength work. More in muscle cramps and electrolytes.

Do Roctane gels replace an electrolyte drink?

Not on their own. At 125–180 mg per packet, Roctane carries up to 3× the sodium of Original, which is useful on warm days and long efforts, but it is still well short of what a heavy sweater loses each hour. Pair it with water, and add an electrolyte drink or capsules for anything long and hot.

Next steps

• Work out your own carbohydrate and fluid targets with the fuel calculator.
• Practise the plan on long training days: train your gut.
• Weighing gels against a bottle of sports drink? Read gels vs sports drinks.

These statements have not been evaluated by a regulatory authority. This product is not intended to diagnose, treat, cure or prevent any disease.