How Many Carbs Per Hour? A Practical Guide for Runners & Cyclists

Finding your number comes down to four things:

1. Your baseline — what your gut can reliably handle right now, based on experience and sport
2. The workout — does it even need fuel? Shorter efforts generally don't
3. Intensity — harder sessions burn more glycogen, thus need more external fuel
4. Sex — female athletes adjust slightly

We'll walk through each and by the end of this article, you'll know how to find your target for any workout without guessing.

Before you think about how long or how hard you're going, you need to know what your gut can actually handle right now; that's your baseline — the hourly rate you can reliably absorb without your stomach turning on you.

This isn't about fitness level or body weight. It's about experience. How long have you been practicing fueling during exercise?

• If you're new to this — less than six months of consistent practice — start around 30g/h for running, 40g/h for cycling. Your gut hasn't adapted yet, and pushing harder will backfire.
• If you've been at it for six to eighteen months, you can handle more. Around 60g/h for running, 75g/h for cycling.
• If you're experienced with gut training — a year and a half or more — you can push toward 90g/h for running, and 100g/h on the bike.

Cycling is a stable, seated position. Running involves constant vertical impact that jostles your stomach with every step. Your gut tolerates more when it's not getting bounced around.

Your baseline is your anchor. Everything else adjusts from here.

Not every run or ride requires calories. Duration decides whether you fuel, and how much of your baseline you actually use.

• Under 45 minutes, skip it. Your glycogen stores have this covered. Water is fine. A carb mouth rinse might give you a small mental boost, but you're not going to bonk either way.
• Between 45 and 75 minutes — the "half dose" zone. Take in about half your baseline. You're training your gut to process fuel at effort. This is practice for the longer stuff.
• From 75 minutes to about two and a half hours — use your full baseline. This is where fueling becomes mandatory.
• Beyond two and a half hours — bump your baseline up about 20%. Your muscle glycogen is seriously depleted and you're increasingly dependent on what's coming in from outside.

How hard you're going changes how fast you burn through glycogen. A two-hour easy run and a two-hour threshold session are not the same fueling event.

• Recovery effort (Zone 1) — your body relies more on fat oxidation. Dial back to about 80% of your baseline.
• Endurance effort (Zone 2) — you're using your full baseline. This is the anchor.
• Tempo effort (Zone 3) — glycogen burn picks up. Bump your baseline up about 15%. A 60g/h baseline becomes roughly 70g/h.
• Threshold or VO2max effort (Zone 4–5) — you're burning through glycogen fast. Add 30% to your baseline. That same 60g/h becomes closer to 78g/h.

The key insight is that duration and intensity work together. A 90-minute Zone 2 long run calls for your full baseline. A 90-minute Zone 4 race calls for 30% more per hour. Same duration, different fueling needs.

The baselines and adjustments above are grounded in research that skews male. If you're a female athlete, there's a slight adjustment worth knowing.

Female athletes generally need about 10% less than the male-derived targets. This isn't about fitness or ability — it's biology. Lower absolute caloric burn, smaller gastric volume, and a natural advantage in fat oxidation all play a role. If the math says 60g/h, something like 54g/h is probably closer to your number.

One exception: during the luteal phase of your cycle (the two weeks after ovulation), bump your target back up by about 10g/h. Progesterone reduces your body's ability to access glycogen, so you need a bit more coming in from outside to compensate.

Below 60g/h, it doesn't really matter what you eat. Gels, chews, honey, maple syrup, real food — whatever sits well and gets carbs in your system works.

Above 80g/h, things change. Your gut has two pathways for absorbing carbohydrates — one for glucose, one for fructose. The glucose pathway maxes out around 60g/h. So if you're pushing higher than that, you need a blend of both to keep up.

Products designed for high intake usually use a glucose-to-fructose ratio around 1:0.8. Maurten, SiS Beta Fuel, and a few others are built this way. If you're going the DIY route at high volume, this is where it starts to matter.

If you're under 60g/h, don't overthink it. Use what works for you.

This is simpler than it sounds. Here's the process:

1. Start with your baseline based on experience and sport. Let's say you're an intermediate runner — that's 60g/h.
2. Check the duration. If you're doing a two-hour long run, that's 75+ minutes, so you're using your full baseline.
3. Adjust for intensity. If it's a Zone 2 effort, your baseline stays at 60g/h. If it's a tempo run at Zone 3, bump it 15% to around 70g/h.
4. If you're a female athlete, knock off about 10% — so that 60g/h becomes 54g/h at Zone 2, or 63g/h at tempo.

That's it. That's your number.

A few more examples:

• A beginner cyclist doing a 90-minute Zone 2 ride: 40g/h baseline × 1.0 (Zone 2) = 40g/h.
• An experienced runner doing a 3-hour Zone 2 long run: 90g/h × 1.2 (150+ min) × 1.0 (Zone 2) = 108g/h. Cap it at 90g/h since that's the running ceiling.
• An intermediate runner doing a 50-minute tempo workout: Half dose zone, so 60g/h × 0.5 = 30g/h, then bump 15% for Zone 3 = roughly 35g/h.

One more thing: build up gradually. If the math says 70g/h but your gut has only ever handled 40g/h, the math isn't wrong, but your gut isn't ready for that leap right now. Gut training takes 2–6 weeks of consistent practice. Don't jump just because a framework told you to — but you now know what you need to work towards.

This framework works. But it's also a lot to hold in your head when you're 90 minutes into a long run and your brain is running on fumes.

That's why I built PODIUM. You tell it your experience level, your sport, and what workout you're doing. It calculates your carb and sodium targets based on duration, intensity, and sex — all the variables we just walked through — and tells you when to fuel with tactical audio alerts.

No spreadsheets. No mid-run math. Just hit start and go.

The "30–60g per hour" advice isn't bad. It's just a starting point that most people never move past.

Your actual number is more specific than that — and now you know how to find it. Baseline first. Duration and intensity adjust. Sport and sex refine. Gut tolerance governs everything.

Figure out your number, practice it in training, and race day gets a lot simpler.