Night-Section Pacing in Trail Racing: The Lonely Battle Under a Headlamp, the Dual Challenge of Pacing and Psychology

Introduction

Races over 100K almost always include a night section. For many runners, the night section is the toughest part of the race: visibility is limited to the beam of your headlamp, body temperature keeps dropping, your circadian rhythm pushes you to sleep, and aid stations feel desolate. Understanding the characteristics of the night section and planning a corresponding strategy is key to your finish rate.

The Physiological Challenges of the Night Section

Night Pacing: How Much Slower Than Daylight?

Night pacing is typically 15-25% slower than daylight, for the following reasons:

1. Limited visibility: Headlamp beam covers 5-15m, making it hard to see terrain ahead
2. Conservative descents: Technical downhills are high-risk at night and require reduced speed
3. Mental fatigue: Combined effect of accumulated fatigue + low mood
4. Temperature management: Wearing too much causes overheating; wearing too little causes chills

Calculating estimated night-section time: daylight pace for that section × 1.2-1.25.

Headlamp Setup: Dual-System with Primary and Backup

For races over 100K, it is recommended to have:

• Primary headlamp: 300-500 lumens, wide beam, 6-8 hour battery life
• Backup headlamp: 100-200 lumens, lightweight, 4-6 hour battery life
• Spare batteries: Prepare 1.5× the estimated night-section time
• Waist light: Red light so runners behind you can see you

Headlamp usage tips:

• Use low lumens on climbs to save battery
• Use high lumens on technical descents to see the trail clearly
• Briefly turn off the light before passing reflective markers to let your eyes adapt
• Drafting behind other runners can save battery

Temperature Management

The temperature challenges at night come from three sources:

1. Dropping ambient temperature: Mountain nights can be 10-15°C colder than daytime
2. Reduced heat production from slower pace: Running slower or walking produces insufficient heat
3. Continuous sweat evaporation: Sweat accumulated during the day evaporates and carries away body heat

Insulation strategy:

• Put on an insulating layer 30 minutes before sunset (don’t wait until you feel cold)
• Add a windbreaker in windy areas
• Head insulation: wear a buff or thin cap
• Hand insulation: thin gloves
• If you stop to rest for more than 5 minutes, wrap yourself in an emergency blanket

Adjusting Your Refueling Strategy

Make three adjustments to your refueling during the night section:

1. Hot food first: Eat hot food at every aid station (soup, congee, instant noodles)
2. Hot drinks for hydration: Carry hot cocoa, ginger tea, or miso soup in a thermos
3. More sweets: Blood sugar drops easily at night, so eat easily absorbed sugars (dried fruit, chocolate)

The Mental Battle: Sunrise Is Your Anchor

The greatest psychological weapon for the night section is “waiting for sunrise.” Set psychological anchors:

• 20:00-22:00: “Entering the night section, slow the pace, eat hot food”
• 22:00-02:00: “Once the first wave of sleepiness passes, things will get better”
• 02:00-05:00: “This is the lowest point; hold on until sunrise and you’ve won”
• 05:00-06:00: “Dawn is near, just 30 more minutes”
• After sunrise: “I made it through the night; every remaining kilometer is a gift”

Micro-Sleep Techniques

If you are severely sleepy during the night section, you can use “micro-sleep”:

• Find an aid station or a safe spot
• Set an alarm for 10-15 minutes
• Close your eyes and rest (you don’t need to actually fall asleep)
• After waking, drink a hot beverage + 100mg of caffeine
• Before departing, briskly walk for 2-3 minutes to wake up your body

Practical Advice

• Train for night running: Do at least 2-3 night training runs before the race to get familiar with your headlamp and adapt to visual limitations
• Avoid running alone at night: If possible, run with other runners to boost morale and safety
• Prepare a surprise: Hide a favorite chocolate bar or a note from family in your drop bag, and take it out when fatigue hits during the night
• Phone contact: If race rules allow, preset a 1-minute call with family at 03:00 AM

Conclusion

The night section is not the “difficulty” of an ultra-trail race—it is the “essence” of it. Whether you can finish a 100K+ race depends largely on how you get through that one night. The next time you plan a 100K, break out the night section and plan it separately: headlamp, insulation, refueling, psychological anchors—none of these can be skipped. Remember: sunrise will always come, and you only need to hold on until then.

Related Reading

• Ultra-Marathon Night Running Techniques: Headlamp Brightness, Night Heart Rate, and Night Refueling Rhythm
• Ultra-Marathon Night Running Strategies: Headlamp Selection and Mental Preparation for Night Running
• Night Training for Trail Running: Headlamp Selection and Safety Rules for Night Trails
• The Illusion of Night Pacing: Why It Feels Faster but Is Actually Slower