Pacing for Ultra-Distance Cycling

You're 30 miles into a 200-mile ride. Your legs feel fresh, your breathing is easy, and the rider next to you is chatting about last weekend's sportive. You glance at your heart rate monitor: 65% of max. Something feels wrong - shouldn't this be harder?

No. You're probably about right.

The Short Version

For ultra-distance rides - anything over 100 miles - most successful riders settle into a surprisingly low intensity range:

• ~55–70% of FTP, depending on duration, terrain, and conditions
• ~60–72% of max heart rate in the early hours
• RPE 3-4 out of 10 - conversational pace

These aren't fixed rules. They're starting points, informed by research and coaching practice. Your ideal intensity depends on your fitness, the event, the weather, how well you slept, and a dozen other factors. But the underlying principle is consistent: if it feels too easy in the first few hours, you're in the right ballpark.

What the Research Suggests

The Ultraendurance Threshold

A study by Neumayr et al. (2004) tracked elite cyclists during the Race Across the Alps - a 525 km event through the Austrian mountains ^[1]. They found that heart rate response decreased roughly 10% every 10 hours, and concluded:

"The ultraendurance threshold lies at about 70% of HRmax in elite ultramarathon cyclists."

This isn't a hard ceiling, but it's a useful marker. Above roughly 70% of max heart rate, cardiovascular strain accumulates faster than most bodies can sustain over many hours. Heart rate naturally drifts upward at a fixed effort - cardiac drift - so starting below this threshold gives you headroom as the hours add up.

Fat Oxidation and Glycogen Sparing

Your body has two main fuel sources: fat (almost unlimited) and glycogen (limited to roughly 90-120 minutes of hard effort). The intensity you ride at determines which dominates.

Research by Achten and Jeukendrup found that peak fat oxidation occurs around 59-62% of VO2max ^[3] - a zone called Fatmax. This maps roughly to the lower end of endurance pace.

Above this intensity, carbohydrate use increases sharply. The difference is significant ^[4]:

Even with optimal fuelling - 60-90g of carbs per hour - you can't fully replace glycogen during exercise. You can only slow the drain. At lower intensities, your body draws more energy from fat, and your glycogen stores last longer.

Your Gut Needs Blood Too

Your stomach needs blood flow to digest food. During exercise, blood is diverted to working muscles.

At intensities above roughly 70% VO2max, gut blood flow drops by 60-70% ^[6]. This triggers a vicious cycle:

1. You can't absorb the food you're eating
2. Undigested food causes nausea, bloating, and GI distress
3. Without fuel absorption, energy drops
4. You slow down anyway - but now you're depleted AND nauseous

Research shows 30-90% of endurance athletes experience GI problems during events ^[6]. Riding at a moderate intensity keeps gut blood flow adequate for digestion. You eat, you absorb, you keep riding.

A Word of Honesty

The percentages in this article - 55% FTP, 65% max HR - are useful as starting points, not as precision targets. Ultra performance is affected by far more than intensity:

• Sleep deprivation - particularly in multi-day events, fatigue accumulates in ways no power meter can measure
• Nutrition tolerance - what your stomach can handle at hour 16 is very different from hour 2
• Weather - headwinds, rain, and heat change everything about sustainable effort
• Mental fatigue - decision-making deteriorates, motivation fluctuates, and perceived effort rises independent of physical load
• Terrain - a flat 200 miles and a mountainous 200 miles are fundamentally different events

The research we've cited comes from controlled studies and elite athletes. Your experience on a wet night in the Pennines may not match the lab data. That's OK - use the numbers as a framework, not a prescription. Listen to your body as much as your devices.

Phase-Based Pacing

Rather than targeting one fixed intensity for the entire ride, a phase-based approach better reflects how ultra events actually unfold:

Early Hours (0-4h): Bank Conservatism - ~60-70% FTP

Ride below what feels natural. Riders will pass you. Let them. Your body is fresh and your RPE will underestimate the true cost of effort. Eat and drink consistently - this is when your gut works best and your appetite is strongest.

Target: RPE 3. Full sentences. You should feel like you're holding back.

Middle Hours (4-8h): Find the Groove - ~55-65% FTP

Maintain a steady output. Your heart rate will drift up 5-10 bpm at the same power - that's normal cardiac drift, not a sign to push harder. RPE rises naturally to 4-5. You may start passing riders who went out harder.

Target: RPE 4-5. Shorter sentences but still conversational.

Late Hours (8-12h+): Manage the Decline - ~45-60% FTP

Power will drop 10-20% despite your best efforts. This is not failure - it's physiology. Heart rate may plateau or even drop as cardiac fatigue sets in. Focus on eating, staying warm, and maintaining forward motion. The riders who paced the first four hours correctly are still moving; many who didn't are not.

Target: RPE 5-7. Focus narrows to the next stop, the next feed, the next 10 miles.

Practical Body Cues

Numbers are useful, but your body gives signals that are often more reliable than a screen - especially as fatigue, sleep deprivation, and weather degrade the accuracy of heart rate and power data:

These cues matter more than any percentage. A heart rate monitor can't tell you that you haven't eaten enough, or that the headwind for the next 30 miles will change your sustainable pace.

Worked Example

To make the ranges concrete, here's what they look like for a typical club rider:

• Weight: 70 kg
• FTP: 265 W (3.8 W/kg)
• Max heart rate: 182 bpm

To put 150 watts in perspective - on a flat road with no wind, that's roughly 28-30 km/h (17-19 mph) for a 70 kg rider. On a typical audax with hills and wind, your average speed might be 24-26 km/h (15-16 mph). That feels slow. It's supposed to.

Compare that to a "normal" ride:

The ultra target is noticeably lower than a typical club ride. That gap catches people out - you know you can ride at 200 watts, so 160 feels like wasting time. But at 200 watts, glycogen burns faster, your gut receives less blood, and fatigue accumulates in ways that will hit you at mile 150.

Real-World Race Data

These ranges align with published data from elite ultra events ^{[2] [1]}:

Even the 24-hour world record holder - one of the fittest endurance cyclists alive - averaged around 55-60% of FTP. And his power still dropped 37% over the course of the ride. These are elite athletes with optimal support crews; the rest of us should expect to ride at or below these intensities.

What the Coaches Say

Chris Carmichael (CTS): Recommends an Intensity Factor of 0.60-0.65 for ultra-distance events. He notes this intensity "would normally be considered a recovery ride to easy endurance ride intensity for a 1-2 hour ride."

Stephen Seiler (Polarized Training): His research found elite endurance athletes spend ~80% of training time below the first ventilatory threshold - roughly 60-72% of max HR ^[5]. This is the intensity where aerobic adaptations happen and where ultra races are sustained.

Phil Maffetone (MAF Method): The MAF formula (180 minus your age) approximates the aerobic threshold ^[7]. For a 40-year-old with a max HR of 180, that gives a ceiling of 140 bpm. For ultra racing, staying well below this ceiling - particularly in the opening hours - is the recommendation.

Dr. Andrew Coggan (Power Zones): Zone 2 (Endurance) is defined as 56-75% of FTP. The lower half of this zone is where ultra-distance rides typically land.

The RPE Test

No heart rate monitor or power meter? The talk test is genuinely useful:

• RPE 3/10: Full conversation. Breathing is steady. You could do this for hours. This is your early-hours target.
• RPE 4/10: Slightly more effort. Shorter sentences but still chatting. Fine for the middle hours.
• RPE 5/10: You can speak but prefer not to. Breathing is noticeable. Too hard for the opening hours of an ultra.

RPE drifts upward naturally - the same 160 watts that feels like RPE 3 in hour one will feel like RPE 5 by hour eight. Starting at what feels "too easy" is the only way to have something left when things get genuinely hard.

What Happens When You Ignore This

The consequences of starting too hard on an ultra ride are well-documented:

• Glycogen depletion (the bonk): Exhaustion, cognitive impairment, inability to maintain pace. The brain runs almost exclusively on glucose - when stores are depleted, decision-making and coordination deteriorate.
• GI shutdown: Nausea, vomiting, inability to eat ^[6]. Once this starts mid-ride, recovery is extremely difficult.
• Muscle damage: Elevated creatine kinase (CK) levels, risk of rhabdomyolysis in extreme cases ^[2]. Higher intensity accelerates this.
• Immune suppression: Depleted glycogen impairs immune cell function.

The cruel irony: going too hard doesn't make you faster over 200 miles. It makes you slower - or it makes you stop.

Planning Your Ultra with PitStopper

Pacing is half the challenge. The other half is knowing where to eat, drink, and rest. Upload your GPX route to PitStopper and search for:

• Cafes and shops - plan fuelling stops every 2-3 hours
• Water points - critical in warm weather
• Toilets - GI issues are common; know where facilities are
• Accommodation - for multi-day events, plan overnight stops

Export your route with POI waypoints to your GPS so you know where every stop is before you start.

Tip: Use PitStopper's clock time feature to check whether shops and cafes will be open when you arrive. A 4am start means your first cafe stop might not open until 8am - plan your pocket food accordingly.

The Bottom Line

Ultra-distance cycling isn't about how hard you can ride. It's about how long you can sustain an effort that feels manageable - while eating, drinking, navigating, and staying mentally together for 12, 18, or 24+ hours.

The science points to a broad sustainable range:

• 55-70% of FTP depending on duration and phase of the ride ^{[3] [4]}
• 60-72% of max HR as a ceiling, with lower in the opening hours ^[1]
• RPE 3-4 in the early hours, accepting natural drift upward

But the most reliable guide isn't a number - it's whether you can eat, breathe comfortably, and think clearly. If all three are true, your pace is probably sustainable. If any one starts to fail, back off before the cascade starts.

The riders who finish 200-mile events strong aren't the ones with the highest FTP. They're the ones who had the discipline to ride well below it - and the awareness to adjust when conditions demanded it.

References

1. Neumayr, G. et al. (2004). "Effect of ultramarathon cycling on heart rate in elite cyclists." British Journal of Sports Medicine, 38(1). PMC1724738
2. Knechtle, B. et al. (2021). "Racing and Training Physiology of an Elite Ultra-Endurance Cyclist." International Journal of Sports Physiology and Performance, 16(5). PubMed 33547258
3. Achten, J. & Jeukendrup, A. (2003). "Maximal fat oxidation during exercise in trained men." International Journal of Sports Medicine. PubMed 14598198
4. Vollestad, N.K. & Blom, P.C.S. (1985). "Effect of varying exercise intensity on glycogen depletion in human muscle fibres." Acta Physiologica Scandinavica. PubMed 4083044
5. Seiler, S. (2010). "What is best practice for training intensity and duration distribution?" International Journal of Sports Physiology and Performance. PubMed 20861519
6. De Oliveira, E.P. et al. (2014). "Gastrointestinal Complaints During Exercise." Sports Medicine. Springer
7. Maffetone, P. & Laursen, P.B. (2020). "The 180 Formula: Heart-rate monitoring for healthy exercise." AIMS Public Health. PMC7142223