Ultra-distance cycling (over ~6 h, 12/24-h time trials, multi-day and bikepacking)
Ride far below fresh thresholds and let the ceiling fall with the hours, eat by the clock because appetite fails in the back half, protect sleep in multi-day races, and cut stopped time before riding harder
The question it answers
A rider is preparing for a single effort longer than ~6 h, a 12-h or 24-h time trial, a multi-day race or a bikepacking event: how hard to ride as the hours pass, what to eat and drink when appetite fades, how to sleep and how to train. A 100-mile TT (~3.5-5 h for most amateurs) belongs to the 3-6 h rows of SYNTH-50 and SYNTH-02; this card starts where they stop. Durability physiology is SYNTH-32; the taper is SYNTH-34.
Default (what to prescribe first)
Intensity: far below fresh thresholds, falling with the hours. In 10 elite men racing 525 km with 12 600 m of climbing (27 h 25 min on average), heart rate averaged 0.68 of HRmax, 78% of the race was below 80% of HRmax and 3% above 90%, and the ratio fell from 0.86 at the start to 0.66 at the end; the authors describe a fall of about 10% every 10 hours (REF-797, B, HR only, no power).
In the lab, trained cyclists lost 5% of power at the first threshold after 139 ± 78 min, on an accelerating curve (REF-143, B, n=12).
Not from a study; the base's own practice: ride steady terrain below rested VT1 power from the start, keep climbs clearly short of threshold, lower both caps as the hours pass, and pace late hours by perceived effort and power, not by a heart-rate target set in the first hours.
Start slower than you feel you can. Optimal pacing beyond 4 h is not established (REF-010, B+, 2008 narrative review). Transfer from running: in 501 runners over 5 editions of a 24-h race, better performers started slower relative to their own 24-h average (r = −.58), while the last 2 h did not separate results (r = .03) (REF-778, B+, observational).
In four editions of a 24-h cycling race, rank grew more predictive as the race went on, but mid-field solo riders' standings stayed least settled (REF-857, B, ranks only): early position says little.
Cut stopped time before riding harder. Transfer from running: in 15 runners over a 106 km mountain ultra, faster finishers were the ones who stopped less (r = −.772) (REF-664, B).
Eat by the clock, not by appetite, and plan the back half. In 14 well-trained riders on a 1,230 km non-stop ride (42:47 h), carbohydrate averaged 57.1 g/h and fluid 392 ml/h, both fell significantly after km 618, and 12 of 14 ate less than they spent (REF-799, B). Not from a study; the base's own practice: start an ultra plan at 60-80 g/h and let rehearsal set the ceiling (SYNTH-02).
Multi-day: do not cut sleep to gain time. In 23 Race Across France riders, more sleep per 24 h went with a higher ranking, and less sleep with worse cognition and slower responses (REF-796, B, correlational).
Decision (who → what)
The middle column is house practice; the right column is what the entries show.
| Situation | What changes (practice) | Source and how sure |
|---|---|---|
| 6-12 h single effort, 12-h TT | Below-VT1 pacing from the start; 60-80 g/h, set by rehearsal; food as well as drinks | REF-143 B (lab, trained cyclists); SYNTH-02 ultra note (practice); single-stage ultra-running stand: 150-400 kcal/h, carbohydrate 30-50 g/h, protein 5-10 g/h (REF-528, A, running) |
| 24-h TT or non-stop ride of 1-2 days | As above, plus a written plan for the back half and for the night | Intake fell after km 618 (REF-799, B); in 8 men on a 24-h relay, weighed intake was 22.8 MJ (943 g carbohydrate) against ~42.9 MJ estimated expenditure, and intake did not track distance (REF-855, B, expenditure from HR); heart rate fell ~10% per 10 h (REF-797, B, elite men); sleep-loss harm grew ~0.4% per hour awake (REF-204, A-, lab, 89% men); caffeine late in the race, particularly when sleep loss threatens safety (REF-528, A, running) |
| Multi-day race with sleep stops | Planned sleep blocks; expect an energy deficit; recovery food at every stop | REF-796 B, correlational; a four-rider RAAM relay team spent 6,420 kcal a day and took in 4,918 (REF-798, C+, case study); the UCI puts extreme racing (>6-h races, stage events) at 10-25 g/kg/day carbohydrate (REF-748, A, elite riders) |
| Multi-day MTB marathon stage race | Prepare repeated hard days, not only long easy volume | 7 amateurs in an 8-day stage race averaged 79.2% of lab HRmax, with 36% of race time in the two highest lactate-anchored HR zones (REF-859, B, HR only) |
| Self-supported bikepacking | Same pacing and sleep logic; food logistics decide intake | No entry studies self-supported riding; the UCI statement names translation to self-supported amateurs as an open question (REF-748) |
| Rider with a history of gut trouble | Longer gut rehearsal, more solid-food variety | In 221 endurance athletes, GI symptoms tracked a history of GI distress (r = 0.37 and 0.51); in a 100/150-km cycling race mean intake was 53 g/h and 4% had serious symptoms (REF-787, B+, self-report) |
| Hot event | Heat acclimation beforehand; pace by RPE; expect to burn less of what you drink | At 32 °C vs 19 °C, exogenous glucose oxidation fell 14-15% and a TT after 2 h was 15% slower (REF-461, B, n=10 trained men); >2% body-mass loss usually costs performance in warm-hot conditions (REF-062, B+); protocol SYNTH-04 |
| Cold nights | Clothing and food, not a drinking target | Hypohydration did not impair submaximal aerobic performance in the cold (REF-062); cold habituation develops over several exposures but is weaker and slower than heat adaptation, with little performance data (REF-562, B+) |
How to progress / periodise
Not from a study; the base's own practice for every number in this section unless a refId is attached:
Sleep strategy (multi-day events)
When NOT to use it / red flags
What the evidence does and does not show
Evidence gaps
How this entry was checked and changed
(cycling-specific evidence is observational field studies, B and two C+, n=1-67; sleep-loss and ultra-running nutrition rest on A-/A reviews from other settings; the training build, pacing caps and sleep plan rest on no ultra-cycling trial)