Hot, humid after-work runs can turn a planned medium-long run into a draining effort fast. If you are asking whether to fuel midweek runs longer than 90 minutes, the useful answer is yes: most marathon runners should practice taking in carbohydrates and fluids on any run that lasts around 90 minutes or more, not only the weekly long run.
The purpose is not simply to avoid a bad run. Midweek fueling helps you complete the intended session with steadier energy, recover better for the next workout, and train your stomach for marathon day. The exact amount depends on duration, intensity, heat, your pre-run meal, and what your gut can tolerate.
Quick Answer
For an easy-to-steady run lasting 90 to 120 minutes, start with 30 to 45 grams of carbohydrate per hour. In hot, humid conditions or during a harder progression, tempo, or marathon-pace session, 45 to 60 grams per hour is often more appropriate.
You do not need to force the usual marathon-race target of 60 to 90 grams per hour into every two-hour weekday run. But skipping fuel entirely is usually a mistake if you are marathon training, especially when the run starts after a full workday and your glycogen stores may not be topped up.
A simple starting plan for a two-hour run is:
- Eat a carbohydrate-focused snack or meal 1 to 3 hours before running.
- Take your first gel or chew serving 30 to 40 minutes into the run.
- Continue with 20 to 25 grams of carbohydrate every 25 to 35 minutes.
- Drink to thirst, using planned fluid access in hot weather.
- Include sodium when you sweat heavily, leave visible salt marks, or run in sustained heat.
Why This Happens
Your body stores carbohydrate as glycogen in muscles and the liver. That fuel supports running, especially when the pace rises, the weather is stressful, or fatigue changes your form and efficiency. A well-fueled athlete can store a meaningful amount of glycogen, but an after-work runner does not always begin with full stores.
Lunch may have been light. Meetings can delay snacks. Coffee may replace food. Then humidity raises cardiovascular strain because sweat does not evaporate efficiently. You may run at an easy pace but feel as though the effort is much harder. Your body can use carbohydrate at a higher rate than expected.
This is why the old rule of “only fuel long runs” is too blunt for marathon training. Duration matters, but context matters too. A 105-minute easy run on a cool morning after breakfast is different from a 105-minute humid evening run after a busy day with limited food and fluid.
Fueling during medium-long runs also trains the gut. Your intestines need practice absorbing carbohydrate while your body is moving and blood flow is directed toward working muscles and skin. If you only use gels on Sunday long runs, you have fewer chances to find a product, concentration, timing, and fluid amount that work.
Step-by-Step Method
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Classify the run before choosing a fuel target.
For a run under 75 minutes, water and normal pre-run eating are usually enough unless it is extremely hot or the session is very intense. For 75 to 90 minutes, consider a small carb serving if you are running hard, starting under-fueled, or managing heat. At 90 minutes or longer, plan to fuel rather than waiting to see whether you fade.
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Start with a conservative carbohydrate target.
Use 30 to 45 grams per hour for your first few fueled medium-long runs. One standard gel often provides 20 to 25 grams. That means a gel roughly every 30 minutes is a workable starting point. If the run includes marathon-pace blocks, hills, or oppressive humidity, move toward 45 to 60 grams per hour if your stomach handles it well.
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Eat before leaving work or before your commute home.
Have a familiar carbohydrate snack 60 to 120 minutes before the run: a banana and pretzels, toast with jam, a bagel, cereal, or a low-fiber bar. Keep fat and fiber modest if they commonly upset your stomach. This snack supports the run, but it does not replace mid-run fuel for a two-hour session.
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Take fuel before you feel empty.
Do not wait for heavy legs, irritability, dizziness, or a sudden pace collapse. Those are late signals. Take the first serving at 30 to 40 minutes, then continue on a schedule. Set a watch alert if you tend to forget while listening to a podcast or managing traffic crossings.
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Match hydration to the conditions.
Drink primarily to thirst, but make fluid available on hot routes. Many runners land somewhere around 400 to 800 milliliters per hour in warm conditions, yet sweat rates vary too much for one number to fit everyone. Carry a soft flask, use a loop past a bottle, or plan a fountain stop. A gel without enough fluid can sit badly in the stomach for some runners.
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Use sodium strategically, not automatically.
Sodium can help replace some sweat losses during long, hot runs, particularly for salty sweaters or runners finishing with crusted salt on clothing. Sports drink, electrolyte tablets, or gels containing sodium can all work. Avoid treating sodium as a cure for every cramp or fatigue issue; pacing, carbohydrate intake, heat acclimation, and fluids matter as well.
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Review the result after each run.
Note the weather, pre-run food, gel timing, fluid amount, stomach comfort, energy in the final 30 minutes, and next-day recovery. Change one variable at a time. That creates a personal fueling plan rather than a random collection of products.
Common Mistakes
Saving all fuel for the long run. This limits gut practice and makes race-day intake feel unfamiliar. Instead, use medium-long runs over 90 minutes to rehearse a simpler version of your marathon plan.
Trying 90 grams per hour immediately. High carbohydrate intake can work well, but it requires practice and often multiple transportable carbohydrate types. Instead, begin at 30 to 45 grams per hour and build only when your stomach, workload, and race goals justify it.
Taking the first gel after the energy crash. Once you are depleted, a gel is less likely to make the final miles feel smooth. Instead, fuel early and consistently.
Drinking huge volumes to compensate for sweat. Overdrinking can cause stomach sloshing and, in rare cases, dangerously dilute blood sodium. Instead, drink to thirst with a practical plan for access, and use bodyweight trends from training only as a general clue.
Testing a new gel during a key workout. Flavor, caffeine, sweeteners, and texture can all cause trouble. Instead, test one new product on an easy run with easy access to a restroom and water.
Checklist or Decision Table
| Run situation | Carbohydrate plan | Fluid and electrolyte approach |
|---|---|---|
| Easy run under 75 minutes | Usually none during the run | Drink to thirst; carry water only in significant heat |
| Easy run, 75 to 90 minutes | Optional 15 to 25 g if under-fueled or hot | Drink to thirst; plan water if conditions are humid |
| Easy or steady run, 90 to 120 minutes | Start at 30 to 45 g per hour | Carry or access fluids; consider sodium for heavy sweating |
| Two-hour run with marathon pace or hills | Aim for 45 to 60 g per hour if practiced | Use regular fluid opportunities and electrolytes when heat losses are high |
| Marathon-specific long run | Progress toward your intended race plan | Practice the exact bottle, cup, flask, and sodium routine you expect to use |
When This Advice Does Not Apply
A planned fueling strategy is not always necessary for every run. If your session is short, gentle, and follows a normal meal, carrying gels may add hassle without much benefit. Similarly, a runner with diabetes, a diagnosed gastrointestinal condition, kidney or heart disease, or a history of exercise-associated medical problems should get individualized advice from a qualified clinician or sports dietitian.
Stop the session and seek medical help for chest pain, confusion, fainting, severe headache, persistent vomiting, or signs of heat illness. Slow down, cool off, and rehydrate after a run if you develop unusual symptoms. Persistent stomach pain, repeated severe cramping, or ongoing fatigue also deserves professional assessment rather than more gels or electrolyte tablets.
Realistic Example
A first-time marathoner runs 10 miles after work on Wednesdays. The route takes about 1 hour 50 minutes, and summer humidity makes the final three miles feel far harder than the pace suggests. Previously, the runner ate a small lunch, drank coffee in the afternoon, carried only water, and began fading around 75 minutes.
A better plan is a banana and plain bagel about 90 minutes before leaving, then one 25-gram gel at 35 minutes, another at 65 minutes, and a third at 95 minutes. The runner carries 500 milliliters of water and loops past a fountain once. On especially hot days, an electrolyte drink replaces part of the water. This delivers roughly 40 grams of carbohydrate per hour without turning a weekday run into a complicated race simulation.
After several weeks, the runner can assess whether 40 grams per hour keeps energy stable. If marathon-pace segments still produce a late fade and the stomach remains comfortable, increasing toward 50 to 60 grams per hour is a reasonable next test.
Final Takeaway
Fueling midweek runs longer than 90 minutes is usually worthwhile for marathon runners, particularly in hot, humid conditions and after a workday. Start with 30 to 45 grams of carbohydrate per hour, take the first serving early, and make fluids available rather than relying on willpower.
Use these runs to practice, not to prove toughness. The best plan is the lowest effective intake that keeps your energy, stomach, and recovery on track, then gradually moves closer to race-day needs when appropriate.
FAQs
Should I take gels on a 90-minute easy run during marathon training?
Yes, taking gels on a 90-minute easy run can be useful, especially if you are training for a marathon. At exactly 90 minutes, you may not need a large amount of fuel for physiological survival, but one gel around 35 to 45 minutes gives you gut practice and can prevent a late-run energy dip. It is particularly sensible for evening runs, hot weather, or days when your meals were light. If you are well-fed, running easily, and finishing near 90 minutes, one 20- to 25-gram serving is enough.
How many carbs per hour should I eat on a two-hour weekday run?
Start with 30 to 45 grams of carbohydrate per hour for a two-hour weekday run. This usually means one 20- to 25-gram gel every 30 minutes after an initial serving around 30 to 40 minutes. Use the lower end for an easy run after adequate food in cool weather. Use 45 to 60 grams per hour when the run includes marathon pace, hills, heat, humidity, or a lower-carbohydrate day of eating. Do not jump to 90 grams per hour unless you have gradually trained your gut to tolerate it.
Do hot and humid runs require more gels than cool-weather runs?
Often, hot and humid runs justify more deliberate fueling, but they do not automatically require dramatically more gels. Heat raises effort and can increase carbohydrate use at the same pace, while humidity makes cooling through sweat less efficient. Begin by keeping your normal carbohydrate schedule consistent, then prioritize fluid access and adjust pace for conditions. If you repeatedly fade despite appropriate pacing and hydration, increase intake modestly by 10 to 15 grams per hour. Test the change on ordinary training days, not during a key race.
Should I drink water with every running gel in humid weather?
Yes, drinking some water with most standard gels is a practical habit, particularly in humid weather. Many gels are concentrated and may cause stomach discomfort if swallowed without fluid, although the exact need depends on the product instructions. Take a few mouthfuls rather than forcing a full bottle at every gel. If you use sports drink for carbohydrate, account for its carbohydrate content before adding multiple gels. The goal is a stomach-friendly total intake, not separate targets that accidentally become excessive.
Can I use sports drink instead of gels for a medium-long run?
Yes, sports drink can replace some or all gels if it provides enough carbohydrate and you can carry or reliably access it. Check the label carefully: many bottles contain far less carbohydrate than runners assume. To reach 40 grams per hour, you may need a substantial volume, which can be difficult in heat. A useful compromise is water or electrolyte drink for hydration plus gels or chews for predictable carbohydrate. Practice the concentration you plan to use because overly strong drink mixes are a common cause of stomach distress.
What should I do if gels upset my stomach on evening runs?
First, reduce the dose and improve the timing rather than abandoning fueling completely. Try a smaller serving every 20 to 25 minutes, take it with water, and avoid waiting until you are already overheated or depleted. Review your pre-run meal as well; high-fat, high-fiber, or very large meals close to running often cause the problem. Test a different format such as chews, drink mix, or lower-sweetness gels on easy runs. If gastrointestinal symptoms are persistent or severe, seek advice from a sports dietitian or clinician.