How sleep science can help you perform your best on summit day.

Sleep is often the first thing people compromise in the midst of busy lives yet it’s easily one of nature’s most critical processes. If we were to take sleep as seriously as we probably should, a full eight hours each night would take priority and we would schedule our days around slumber. But with jobs and kids and happy hours and movies and concerts and stress and screens, we unfarily sacrifice sleep on a daily basis.

The importance of a good night’s sleep is amplified when you are hiking in the Colorado high country. Lightning storms can be expected every afternoon from May until early October. Many mountain trails travel above treeline, making them vulnerable to the full brunt of violent afternoon thunderstorms. You can mitigate storm danger by getting an early start, but often that means hitting the trail by 4:00 a.m. or earlier—plus a few hours of drive time to reach the trailhead. Many summit days begin in a mental fog and end with a wearisome drive home.

“Sleep loss is cumulative,” says Dr. David McCarty, MD and the Medical Director of the Colorado Sleep Institute. “You don’t make up for a week of bad sleep in a single night.” While this may seem obvious to anyone who loses sleep on a regular basis, the science behind why has only come to light in the past decade.

The glymphatic system, a means of purging metabolic waste from the brain via the central nervous system, was uncovered by sleep scientists in 2012 using advanced brain imaging.  McCarty explains the complexities of the glymphatic system with an easy-to-understand example: fumes in the attic. “It’s a linear system,” explains McCarty. “When you’re awake, you’re building fumes, and when you sleep you’re clearing them out. It takes a full eight hours of sleep each night to clear out the fumes.” The more sleep deprived a person is, the more neurotoxins accumulate, to the point where a single good night’s sleep won’t repair the damage of multiple nights of little sleep.

The upshot for mountain hikers? To achieve your best summit day, focus on good sleep for three to five days before your attempt. The catch? Not everyone sleeps the same.

Night Owls and Morning Larks

When it comes to sleep, there are two kinds of people: night owls and morning larks. And when it comes to hiking, morning larks—those who cheerfully bound out the door on a 5:00 a.m. run—have an advantage over night owls—people who only come to life in the afternoon. But here’s the injustice.

Night owls are not owls by choice,” says Matthew Walker, PhD, in his book Why We Sleep: Unlocking the Power of Sleep and Dreams. “They are bound to a delayed schedule by unavoidable DNA hardwiring.”

But that doesn’t mean night owls are doomed to spend their mountain time in a cerebral haze. It just means they have to work harder to feel good during early morning starts.

Play to Your Circadian Strengths

Night owls can shift their sleep patterns to a degree, with the goal being to minimize the cumulative effects of sleep loss and perform better in the pre-dawn hours. But McCarty says the human body can only effectively adjust sleep time by about 30 minutes earlier per night. This explains why a person who normally goes to bed at midnight will toss and turn for hours when they try to drift off by 9:00 p.m.

Instead, try to go to sleep 30 minutes earlier each night over the course of three to five days before your big endeavor. Taking a 0.5-milligram dose of over-the-counter melatonin five hours before sleep will help the body ease into its natural sleep rhythm without bringing on sudden drowsiness. Minimizing exposure to lights like computer screens and TVs earlier in the evening will help as well. Practice this religiously, and by the time summit day arrives, the night owl should be well rested and less mentally fatigued by closing the gap between their normal wake time and their early morning alarm.

Trailhead Camping or Early Start?

Sleep affects more than mountain safety; it also impacts your drive to the trailhead. Night owls should sleep at trailheads the night before their big hike, as they likely will be mentally intact for an after-drive work and can benefit from a sleep cycle closer to their natural rhythms. Morning larks can often sleep at home, especially if they are strong hikers who can start on trail at 7:00 to 8:00 a.m. It’s worth noting that morning larks can suffer a “breakthrough drowsy episode”—a normal and natural bit of fatigue in the course of a day—between 2:00 to 4:00 p.m., which is often when the drive home begins. They might catnap after a hike to ramp up energy for the drive. If a night owl and morning lark hike together, the morning lark can drive to the trailhead and the night owl can take the drive home.

The Perfect Altitude

One of the problems with sleeping at trailheads is that altitude adjustment can contribute to a poor night’s sleep. Thus, a night owl who is trying to gain an advantage by sleeping at a trailhead may actually end up more impaired than if he had left from home. From an unscientific standpoint, I’ve found that Front Rangers who live at 5,000 – 6,000 feet will get the best trailhead sleep at 8,500-9,000 feet (McCarty supports this observation).

“Sleep quality varies by magnitude at elevation,” he explains, “and at 10,000 feet, many people will experience high altitude periodic breathing.” Anyone who has shared a tent with a grunting, snoring tent-mate knows the symptoms all too well: shallow, non-rhythmic breathing, with pauses that can last up to 20 seconds between breaths. This phenomenon is more likely to occur in men than women. High altitude periodic breathing doesn’t mean your body isn’t acclimating, but lower oxygen levels can result in poor sleep, leading to sub-par performance the following morning. It’s best to sleep lower than 9,000 if you only have a single night out.

If needed, McCarty suggests over-the-counter sleep medications (taken at a half-dose) or the high-altitude drug Diamox (prescription) to ward off high altitude periodic breathing, especially if you absolutely have to sleep at an elevation over 10,000 feet (such as on a hut trip).

In the Wild

As a night owl who has spent years exploring the best sleep strategy for a weekend-day summit, I find sleeping at a trailhead / or camp no higher than 8,500 feet gave me my best shot at both sleeping well and crushing it the next day. Using McCarty’s three-to-five-day sleep strategy, I have felt even better and stronger than just sleeping at the trailhead—a few days of intentional preparation made a noticeable difference.

Elevation Outdoors contributing editor James Dziezynski’s guidebooks Best Summit Hikes in Colorado and Best Summit Hikes: Denver to Vail are available on Amazon and at independent Colorado outdoor retail and book stores.