What It Takes to Everest in 7 Hours
And why you can’t do it.
A couple of months ago, a Virginian took the official Everesting record, bringing the record time on this unofficial, solo race under the 7 hour barrier for the first time. Since its birth as a discipline in the 1980s and popularization by the Hell’s 500 in the 2010s, Everesting has never had a bigger moment than the long, lockdown summer.
Every time a rider grabbed the men’s title, it seemed impossible that the time could be bested. Over the summer, the record slipped down to just under 8 hours by Phil Gaimon, to 7:40 by Keegan Swenson, 7:29 by Lachlan Morton, 7:27 by Alberto Contador, then fell off a cliff with Ronan McLaughlin’s 7:04 before it finally settled at the 6:59 put up by Sean Gardner. Some of these advancements have been helped by improved route selection, others by equipment tweaks, and still others by luck of the weather but, regardless, it takes an incredible engine and amount of work to get anywhere near these times.
What did it take for Sean Gardner to sneak under the 7 hour barrier? Great planning, great climbing, and a whole lot of food. I’m going to look a bit at what Sean did, but also focus on the physiologic challenge in general to show just what type of incredible effort this took.
The Route
When perusing the everlasting records, one thing is immediately clear, your climb has to be over a 10% grade to get close. Only one of the top 13 riders has a route <10% in grade, and most are 11 or above. Sean Gardner’s ride up and down (and up and down and up and down and up and down…) Tanners Ridge Road in Virginia was along a 15.5% stretch of blacktop. Truly nastily steep. The second placed rider, a barely 5 minute slower Ronan McLaughlin, climbed a 14.2% segment in Donegal, Ireland for his incredible time.
Such a steep route reduces total distance covered, from 170km for Keegan Swenson’s 7:40, 11% climb to just 116 for Sean Gardner’s. This trims a lot of fat off the route. But that’s not the only important part.
Other than being generally car free and shaded to help get you through a long day, the route needs to be pretty straight so you can rip it on the descent. Descents don’t last long in a good everesting attempt (Alberto Contador’s were less than 60 seconds), but they do happen often (Contador went down 77 times). The less you have to hit the brakes on the way down, the faster you can head uphill again.
The Bike
Some riders have made special tweaks to their bikes, like Phil Gaimon’s famous chopped drops and absent rear brake, but most have climbed completely normal bicycles up to the top of these climbs. They’re top level, ultralight bikes with carbon wheels and weights in the high 5 or low 6 kilogram range, but they’re still regular bikes that you and I could buy off the shelf. Nothing too special here.
The only important bit, according to Sean, were the disc brakes. To descend as fast as possible, he ramped up to maximum speed, zipped down the whole descent, and slammed on the brakes at the bottom 52 times. According to what he told VeloNews, he’s not certain rim brakes could have handled the strain. As it was, the fierce braking warped his discs and necessitated replacement afterward.
The Body
This is where things get serious. Mathematically, it takes 6500 kilojoules of energy to raise a 65 kilogram man and his 6 kilogram bike as high as Mount Everest. That’s actually not too bad. A 175 pound 35 year old needs about that much energy to stay alive each day. It’s approximately the basal metabolic rate of the average human. Unfortunately, the math doesn’t work quite as cleanly as that. While riding up and down for 7 hours, Gardner is also surviving, so you can add those 6500 kilojoules of riding to the 3000ish kilojoules of surviving he’s doing. There’s one more problem too, efficiency.
Humans are only about 20–25% efficient when riding a bike. It’s not a great number. The rest of that energy goes to heat production, posture maintenance, thinking, breathing, etc. An elite cyclist like Gardner is probably near the top end of that efficiency range. To make my math easier lets give him a 25% efficiency rating. That means the 6500 Kj it takes to mathematically move someone from bottom to top actually becomes 26,000 Kj flowing through his body as a rough an estimate.
Up ’til now, we’ve been working with mathematics to estimate Sean’s effort. Fortunately, thanks to Hunter Allen’s article about the attempt on Velonews, we can put some real numbers behind this effort. Hunter’s analysis showed that Sean averaged 308 watts per climb on the 52 efforts, each took just over 7 minutes, and each descent took about one minute, giving lap times of just over 8 minutes total. For the whole 6hr, 59min effort, Sean averaged 273 watts. Math time!
A watt is one joule per second, so we can multiply Sean’s average watts by total time to find the amount of kilojoules he used to climb. 273watts x 420min x 60s/min = 6,879,600 joules, or 6880 Kj of work. Almost right on the estimate from above. If we multiply that by 4 to account for his body’s inefficiencies and other work, that pops out to 27,518 Kj. Switching to the calories we’re more familiar with, it took Sean almost 6600 calories to pull off that effort, more than 900 per hour.
Endurance Performance is Mostly About Calories Used Per Hour
There’s a fair bit of argument about how many dietary calories a human can process in an hour, but most sources settle on a maximum of 500–600. That would put him about 400 calories per hour short of what is needed.
Fortunately, the body can also store quite a few, ready for mobilization at any time. The quick-access calories would be stored as glycogen, a complex carbohydrate chain that is stored in muscles and the liver. Unfortunately, once glycogen is in a muscle, it can’t get out. Glycogen storage in the biceps can never make it to the hamstrings, and vice-versa. The way to get more glycogen into the bloodstream so other muscles can use it is via the liver. Unfortunately (again) the liver can only store about 200 grams of glycogen, just 800 calories.
Large muscles can store up to 50 grams of glycogen, about 200 calories per muscle. I can’t make an exact estimate of how much work each muscle in Sean’s body did (well, I can, but it would take forever and be ridiculously complicated, so I won’t), but it’s safe to say that 200 calories isn’t enough to keep your Rectus Femoris (a quad muscle) working for 7 hours. Where did the energy come from then?
Mostly, fat.
Except at extremely high intensity, the body never stops burning fat. Even someone incredibly thin like Sean has thousands of fat calories available since fat is about 3,000 calories per pound. This is great news, since it means there’s plenty of energy available to get him through a painful 7 hours. Like most things we’ve seen so far though, there’s a twist. Fat can’t be accessed quickly.
Human metabolism is limited to about 1g of fat burn per minute, about 9 calories worth. Additionally problematic, this maximal rate can only be reached at VO2max levels at around 65%. Work harder than that and the rate of fatty acid oxidation goes down rapidly. According to Hunter Allen’s analysis, Sean’s FTP is about 360 watts, so the 308 watts he used in each climb is about 70% of his VO2max level. Perfect! On every 8 minute repetition, his body can produce up to 72 calories from fat, about 450 calories per hour. Perfect again! Unlike glycogen, these calories can be used everywhere, and total, the consumed calories plus the calories from fat get Sean to about 950 available calories per hour, just a bit more than he needed to do the climb.
If Sean weighed 3 kilograms more, he probably wouldn’t have been able to access enough calories to make it through the day. This effort came down to marginal differences in fueling, weight, and caloric access.
Could You Everest in 7 Hours? No.
If you weigh 65kg and have an FTP around 350, maybe, but very few people do. Sean pumped out 4.73 watts per kilogram for almost 7 hours and still just barely made it. This effort is near the limits of human performance and it’s unlikely that anyone will blow it out of the water. There are some marginal gains that others may be able to make: a lighter bike, an even steeper route, beneficial barometric conditions, etc. but there aren’t many physiological gains left. The caloric mobilization involved was massive and few could get anywhere near using that many calories in such a short time at such a low weight.
How Fast Could You Go?
Fortunately, there’s a chart for that. Well, there is now that I made it. This chart is solely based on nutritional requirements, not wattage. It assumes that you too can burn 950 calories per hour for an essentially unlimited amount of time and judges how long it would take you based on those energy demands. The heavier you are, the more energy it takes to do the climb, but heaviness does not equal energy availability. Sean’s body can mobilize and utilize calories just as fast as yours can (and probably faster) no matter the weight.
Here’s the chart:
Where do you end up? Or do you think you can do better than my graph predicts? It’s possible. Some people can grab 1,000 or even 1,100 calories per hour, letting them potentially ride at an average of 320 watts for the whole thing. That would put them at a sub 6 hour Everest. It may be physically possible, but it’s pretty darn unlikely. They’d have to climb at an average of 373 watts for a total of 312 minutes. Wow.
If someone does, they’re really at the limits of human performance, but I just don’t think it’s possible. Maybe Hugh Carthy or Tadej Pogacar will take a few hours this winter to prove me wrong but I‘m not holding my breath.
Luke is a cycling coach and physiologist from Richmond, VA who rides and races bikes all over the country (though not right now). He’s an expert on the body in motion and its response to exercise and loves to share his knowledge with others. Find him @LukeHollomon everywhere.
