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⏵ Course guide · Arizona ultra

Adrenaline Night Runs Course Guide

The Adrenaline Night Runs is one of Aravaipa’s Insomniac night races, a looped desert 50K (with 25K, 15K, 10K, and 6K options) run entirely after dark by headlamp on the rolling single-track of McDowell Mountain Regional Park. There is no big mountain to climb here. The challenge is the night, the loops, and keeping yourself fed and awake into the small hours. I’ll walk you through the course first, then give you a pacing and fueling plan built for an after-dark ultra. There are free calculators along the way to dial in your own numbers.

⏵ At a glance

Adrenaline Night Runs quick facts

Date
Saturday, May 23, 2026 (an evening start)
Location
McDowell Mountain Regional Park, Fountain Hills, Arizona (start/finish at the Four Peaks Staging Area)
Distances
50K, 25K, 15K, 10K, and 6K, all on desert single-track
Elevation gain
Rolling desert, roughly 800 ft of climbing per long loop, so the 50K stacks up over repeated loops (no big mountain)
Start times
50K 7:00 PM, 25K 7:15 PM, 15K 7:30 PM, 10K 7:45 PM, 6K 8:00 PM
Cutoff
50K must leave on the final long loop by 1:00 AM and the final short loop by 3:15 AM, with a 5:00 AM overall cutoff (about 10 hours)
Qualifier
No Western States, UTMB, or Hardrock qualifier status listed by the race

These facts come from the official Aravaipa race page and UltraSignup. Check the current date, start times, cutoffs, and aid stations in the race-day details before you commit. Race logistics change year to year.

The course: where Adrenaline is won and lost

This is a looped race, not a point-to-point. The 50K is built from a long loop and a short loop on the rolling Sonoran single-track of McDowell Mountain, touring the Escondido and Cinch trails plus the scenic ridge, with everything funneling back to the Four Peaks start/finish along the Shallmo Trail. You pass through the start/finish between loops, which is both a gift and a trap.

The loops: fast desert single-track, run blind in the dark

On paper this is a friendly course. Rolling desert trail, roughly 800 feet of gain per long loop, plenty of fast smooth running with a few rockier, more challenging sections mixed in. In daylight a lot of it would feel cruisable. The catch is you never see it in daylight. Everything happens inside your headlamp beam, so the smooth stuff is harder to open up on and the technical bits sneak up on you. Run within the light you can actually see, especially early when you feel fresh and want to send it.

Because it loops, the second time around you sort of know what is coming, and that helps. Use the first lap to learn the rough spots and the places you can run relaxed, then run the repeats smarter. Watch for cactus, loose rock, and the occasional desert critter crossing the trail. None of it is dangerous if you are paying attention, but your attention is the thing that fades at 2:00 AM.

The start/finish trap: the loops giveth, the chair taketh away

You roll through the Four Peaks aid station every loop, and that is genuinely great. You can stash a drop bag, restock, swap a light, grab real food. It also means a warm chair and people you know are right there every lap, and that chair has ended more 50Ks than any climb on this course. The loop cutoffs are real: you have to leave on your final long loop by 1:00 AM and your final short loop by 3:15 AM. Dawdle a few minutes too long each lap and those deadlines arrive faster than you think.

Have a plan for every start/finish stop before you get there. Know what you are grabbing, do it, and get back out. Treat the aid station like a pit stop, not a hangout, and the 5:00 AM overall cutoff stays comfortably out ahead of you.

The night itself: the real opponent

The thing that actually makes Adrenaline hard is that it asks your body to run an ultra during the hours it expects to be asleep. After a 7:00 PM start, the back half lands somewhere in the 1:00 to 4:00 AM window, which is exactly when your energy, your mood, and your willingness to keep eating all bottom out. The desert also cools off after midnight, so what felt warm at the start can get genuinely chilly late.

Plan for the low. It is coming, and knowing that takes most of its power away. Keep eating on a clock, keep your light bright, throw on a layer before you are cold rather than after, and remember the sun does not have to come up for you to finish. Most people who DNF here are not broken, they are just tired and cold and let the chair win.

Pacing strategy for a looped night 50K

With no big climb and lots of runnable desert, Adrenaline is more about even, repeatable effort than grinding up a mountain. The trick is pacing your loops so the last one looks like the first, and not burning your buffer to the cutoffs early.

Pace by even effort, lap to lap

Run the first loop a notch easier than feels right. The course rewards a steady, even effort more than a hot start, because the time you bank by hammering early gets paid back with interest when your legs and your head go flat after midnight. A good Adrenaline runner is one whose last loop is barely slower than the first. Use a grade-adjusted pace to set an honest target for the rollers so you are not accidentally surging every little rise, which is exactly how you fry yourself on a deceptively runnable course.

Build a finish prediction and work back into the loop cutoffs

Do not guess your night-50K finish off a fresh daytime road time. Running in the dark on tired legs is slower than the same effort in daylight, and you want to know your realistic window before you start so you can work back into the 1:00 AM and 3:15 AM loop cutoffs. A finish prediction that accounts for the terrain tells you roughly when you need to be rolling through the start/finish on each lap, so you actually know how much buffer you have instead of finding out the hard way at the cutoff table.

⏵ Free tools to pace this course

Fueling strategy for an after-dark ultra

Most runners are out on the Adrenaline 50K for somewhere around 5 to 10 hours, and the whole effort lands at night, when your appetite quietly disappears. That makes a steady, scheduled fueling plan just as important as your legs.

Carbs: eat on a clock, not on hunger

For a 5 to 10 hour effort, aim for around 60 to 90 grams of carbohydrate per hour, and only push the higher end if your gut is trained for it. The hard part at night is that you will not feel hungry, so do not wait to feel like eating, eat on a timer. The Four Peaks start/finish is fully stocked every loop with real food (think quesadillas, grilled cheese, PB and J, fruit), and the Escondido remote aid out on the long loop catches you each lap too, so you are never far from calories. Use that, but still carry what you need between aid and practice your exact race-night carb rate on a late long run so it feels normal, not like a 2:00 AM experiment.

Sodium, fluid, and the late-night chill

May nights in the Sonoran desert can still start warm and then cool off hard after midnight, so your fluid and sodium needs shift as the night goes on. Early, while it is warmer, keep drinking and keep sodium up (often around 400 to 700 milligrams per liter of fluid, more if you are a heavy or salty sweater). Later, as it cools, you may drink less, but keep nibbling salt and calories so you do not bonk while you are also getting cold. Weigh yourself before and after a hot long run to find your real sweat rate, then build the plan around your own number rather than a generic one.

⏵ Build your fueling plan

Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a night effort with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.

⏵ Train for it with Summit Line

Get a race-day plan built around YOUR fitness, this exact Adrenaline loop profile, and your projected splits. Summit Line reads your real training, builds a plan for an after-dark ultra, and rehearses your fueling so race night is something you execute, not guess at.

Start free →Explore the demo

Adrenaline Night Runs FAQ

How hard is the Adrenaline Night Runs 50K?

It is a runnable desert 50K, but the night is the hard part. The course is rolling Sonoran single-track at McDowell Mountain with no big mountain climb, roughly 800 feet of gain per long loop, so on paper it is one of the friendlier 50K profiles in Arizona. What makes it tough is that you run the whole thing in the dark by headlamp after a 7:00 PM start, on tired-feeling legs, on a looped course where the mental game and staying awake matter as much as fitness. The 5:00 AM overall cutoff gives a fit, well-paced runner room, but you have to keep moving through the small hours.

How much climbing is in the Adrenaline Night Runs 50K?

Not a lot by ultra standards, and that is the appeal. The terrain is rolling desert single-track with roughly 800 feet of climbing per long loop, so the 50K total adds up over the repeated loops rather than coming from one big climb. There are fast smooth sections plus a few more challenging rollers through the Escondido, Cinch, and Scenic Ridge trails. The exact total varies with the year and the loop layout, so confirm the current course map with the race.

What time does the Adrenaline Night Runs start and finish?

It is a night race. The 50K goes off at 7:00 PM, with the shorter distances starting in waves right after (25K at 7:15, 15K at 7:30, 10K at 7:45, and 6K at 8:00). The 50K overall cutoff is 5:00 AM, so the front of the race finishes well before dawn and the back of the pack runs deep into the night. A bright headlamp is required, and a backup light is a smart call.

What are the cutoff times for the Adrenaline Night Runs 50K?

The 50K has loop-based cutoffs, not just one finish limit. You must leave the start/finish on your final long loop by 1:00 AM and on your final short loop by 3:15 AM, with a hard 5:00 AM overall cutoff (about 10 hours from the 7:00 PM gun). Because you pass through the start/finish between loops, those checkpoints come up fast if you dawdle in the aid station. Confirm the exact loop cutoffs in the current race-day details before you start.

What is the course and terrain like at Adrenaline Night Runs?

It is a looped course on rolling Sonoran desert single-track in McDowell Mountain Regional Park, built from a long loop and a short loop that share the Shallmo Trail back to the start/finish. You tour the Escondido and Cinch trails plus the scenic ridge, with fast smooth runnable stretches and a few rockier, more challenging sections. There is a fully stocked aid station at the Four Peaks start/finish and a remote Escondido aid station out on the long loop that you pass every lap, plus water out at the Pemberton trailhead. Footing is generally good, but cactus, rocks, and the occasional critter are real at night, so watch the trail in your headlamp beam.

How should I prepare for running the Adrenaline 50K at night?

Train your body to run and fuel when it normally sleeps. Do a couple of late-evening or full-dark long runs in the weeks before so your stomach, your eyes, and your headlamp setup are all dialed before race night. Carry a bright primary light and a backup, bring layers for the temperature drop after midnight, and have a plan to keep eating on a schedule even when you are not hungry in the small hours. The looped format helps here: you can stash supplies at the start/finish and reset your head each lap, so break the race into loops instead of one long 31-mile slog.

This guide is independent and for planning only. The course details, dates, start times, cutoffs, and aid stations come from public sources and can change year to year, so confirm the current specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.