Night Running and Headtorch Strategy for Trail Ultras

Runners spend a disproportionate amount of preparation time on the parts of an ultra they can see coming - the climbs, the distance, the heat. The night section gets a headtorch bought two weeks before the race and not much else, which is a mismatch, because for anyone racing past ten or twelve hours, the night is often where the race is actually decided.

Why it's harder than the fitness numbers suggest

Night running degrades performance through several mechanisms that have nothing to do with how fit you are.

Depth perception and footing accuracy drop. A headtorch beam flattens terrain in a way daylight doesn't - roots, rocks, and camber are genuinely harder to read, and the technical sections that felt manageable on a daytime recon run demand real concentration at night.

The circadian low hits regardless of training. Core body temperature and alertness both bottom out in the 2-4am window for almost everyone, trained ultra runner or not. This isn't fatigue in the training sense - it's a biological low point that arrives on schedule whether you've paced well or not.

Navigation errors cluster at night. A missed course marking that would be obvious in daylight is easy to miss in a narrow beam of light, especially when tunnel vision sets in from hours of staring at the small circle your headtorch illuminates.

Temperature management gets harder. A 10°C or greater overnight drop is common in mountain terrain, and runners who were managing heat carefully all afternoon frequently forget to layer up as the temperature falls, because the change is gradual enough to miss while focused on moving - the cold-weather guide covers layering and the early signs of hypothermia worth knowing before a cold night section.

Headtorch setup

Lumens and beam type by terrain:

More lumens isn't automatically better. A very bright narrow spot beam on technical terrain lights up the trail thirty metres ahead while leaving your actual footing in shadow, which is the opposite of what you need when the thing that matters is the next three steps.

Carry a genuine backup light, not just spare batteries. Lights fail - a dropped headtorch, a broken clip, water ingress. Most 50 mile and 100K+ races with mandatory night sections require this for exactly that reason, and it's worth carrying even when it isn't required.

Use a red light mode at aid stations and around other runners. It preserves your own night vision for longer and doesn't wreck everyone else's.

Consider a dual-light setup on technical terrain: headtorch plus a low waist or handheld light. A head-mounted light alone casts shadows that move exactly with your gaze, which means the shadow of a rock is always falling on the same side you're looking - hiding the thing you most need to see. A second, lower light source throws shadows from a different angle and makes technical footing dramatically easier to read. This is the single highest-value gear change most runners have never tried.

Training for it

Run at least one long training run at night, on terrain as close to your race terrain as you can find, before race night. This is the only way to genuinely test your gear, your pace expectations, and how your own alertness holds up - and it should happen during your build, not the week before the race.

Test your full lighting setup on that run, not a five-minute driveway check. Battery life under real cold, real duration, and real technical demand is different from what the packaging promises.

Practise changing a headtorch battery or swapping to your backup light in the dark, ideally while moving on rough ground. It's a fine-motor task that's much harder than it sounds when you're tired and your hands are cold.

Adjust your pace expectations honestly. Night running on technical terrain typically costs 10-20% versus the same section by day, purely from reduced visual information. Build that into your splits rather than being surprised when your night pace doesn't match your recon-run pace.

What actually goes wrong at night

Nutrition compliance drops. Eating requires a small executive decision every time, and decision-making is exactly what's degraded at 3am. Set alarms or fixed intervals rather than relying on remembering to eat - the same discipline the fueling guides describe for daytime racing matters more, not less, after dark.

Mild hallucinations are a real and reasonably common phenomenon in ultras that run through a full night, especially 100 milers - shapes in peripheral vision, a sense of someone running just behind you, misread objects on the trail. They're not dangerous in themselves and tend to resolve with caffeine, a short rest, or simply daylight, but they're worth knowing about in advance so they don't feel alarming when they happen.

Micro-sleep is the more serious version of the same fatigue. Momentary lapses in attention on technical terrain, at speed or on exposed ground, are a genuine safety issue. If you notice your attention repeatedly drifting, that's the signal to slow down, take caffeine if you're using it, or - on a race that allows it - take a short deliberate rest rather than pushing through and risking a fall.

Race strategy for the night hours

Expect the low point. Almost everyone who runs through a full night hits a rough patch somewhere in the small hours, independent of fitness or pacing. Runners who know this in advance treat it as a normal, temporary phase of the race. Runners who don't often mistake it for a sign that something has gone wrong, and make bad decisions - quitting at an aid station, changing a fueling plan that was actually working - based on a feeling that would have passed in forty minutes.

Time caffeine deliberately if you use it, rather than reflexively at every aid station. Roughly 100-200mg timed for the hour or two before your expected low point does more than the same amount spread thin across the whole night.

Run with someone through the hardest hours if you can. Conversation is one of the more effective tools against both the circadian low and the attention lapses that lead to falls - and it's a large part of why pacers are allowed in the overnight sections of many 100-mile races.

I had an athlete a few seasons ago whose first hundred-mile attempt ended at an aid station around 3am - not injured, not out of fuel, just convinced by the low point that she couldn't continue, and nobody around her had told her that feeling was normal and temporary. Her second attempt the following year, on a harder course, she hit the same low at almost the same hour, recognised it immediately because we'd talked through exactly what it would feel like, sat down for four minutes, ate something, and finished with two hours to spare. Nothing about her fitness changed between the two races. What changed was that the low point stopped being a surprise.

The mistakes

1. Buying a headtorch two weeks before the race and never testing it on a real night run. Battery life, comfort, and beam pattern all reveal problems only under real use.
2. Using a single narrow-beam light on technical terrain. It lights the distance while hiding the ground under your feet.
3. No backup light, or only spare batteries for the same unit. If the headtorch itself fails, batteries don't help.
4. Not adjusting pace expectations for night sections, then panicking when splits slow down for reasons that have nothing to do with fitness.
5. Treating the 2-4am low as a crisis rather than the near-universal, temporary phase it usually is.
6. Forgetting to layer up as temperature drops, because the change is gradual enough to miss while focused on moving.

If your goal race has a significant overnight section, the pacing guide covers the daytime half of the strategy - together they cover the full race. Working through night-specific pacing and gear for a specific course is exactly the kind of detail 1:1 coaching bends around your actual event.