The Outside Blog

Biking : Science

How to Prepare for a High-Altitude Race

We know the feeling (Outside's headquarters are at 7,000 feet). Doing any sort of activity at high elevation, even just a simple walk, leaves you feeling like all your past months of training didn’t even happen—and that you’ve been smoking a pack a day instead.

So what are you supposed to do if you live at sea level and want to travel for a race that is at altitude? Surprisingly, you don’t have to feel like you’re dying the whole time—if you flow the rules of high-altitude racing.

Your Body on Altitude

No matter how good of shape you are in, it doesn’t matter when you head up to the mountains, at least for the first few days while you are acclimating. That’s because your body is experiencing hypoxia, where your blood carries a lower level of oxygen than normal. The wheezing and shortness of breath you experience is your body trying to compensate for these lower oxygen levels.

“Your heart rate goes up to try to get more oxygen into your lungs—it is trying to increase the  pumping of your heart to deliver and transport more oxygen to your tissues,” says Robert S. Mazzeo with the Department of Integrative Physiology at the University of Colorado. Altitude also causes hormonal changes to occur—like the pumping of adrenaline to help with oxygen transportation and delivery. This all happens when anyone is exposed high altitude, but if your body doesn’t acclimate well, you can get acute mountain sickness, which unfortunately feels a lot like a bad race anyway—headache, nausea, and vomiting.

Arrive Early and Lower Your Intensity

So how do you complete a high-altitude race when you train at sea level? Since we don’t recommend blood doping, and a hyperbaric chamber will set you back a few thousand dollars, aim to get to the race location a week in advance and stay active—which accelerates the acclimation process. Don’t, however, workout at your full intensity and volume. Instead, reduce your intensity by 10 percent and volume by 10 to 20 percent, over your taper, too, says Lance C. Dalleck, an assistant professor of Exercise and Sport Science at Western State Colorado University and researcher for the High Altitude Performance Lab. Take the first day or two off, and if you aren’t experiencing symptoms of acute mountain sickness, start training, but slightly less.

But be sure to prepare mentally, as your race pace will be slower and dehydration sets in quicker. Rather than trying to maintain your typical pace, consciously slow yourself down to avoid blowing up.

Timing Is Key

If you can’t arrive a week in advance and get your body acclimated, schedule your arrival time as close as possible to race day, says Dalleck. Avoid racing between 24 to 72 hours at altitude and instead head up the night or morning before. “That is when you are suffering the most and are most prone to mountain sickness, when you are really starting to acclimate,” Dalleck says of the one-to-three day period. “Before 24 hours, you haven’t really started acclimating... If you race right away, you will beat all of that happening. Your performance on day one at altitude will be better than on day two, three, or four.”

You can also try to get to a somewhat higher altitude at home, if possible, since preexposure to altitude can start that acclimatization. Aim to spend four or more hours at 5,000 plus feet a few times in the month leading up to the race.

If you still end up feeling like crap the whole race, don’t sweat it. It’s not you—it’s genetics. “We see a lot of variability in athletes at altitude,” says Dalleck. “Some individuals don’t seem to be as impacted by the altitude.  Others at sea level might be world class athletes and at altitude, they are just anybody else.”

Read More

The Surprising Reason Gluten-Free Diets Actually Work

Gluten-free diets shouldn’t work. The science, as shown by recent research, isn’t on their side. But talk to the athletes who willingly deprive themselves of gluten (a protein found in wheat, rye and barley) and they’re likely to respond with miraculous tales: gone are their days of feeling bloated and fatigued. They’ve lost weight. They recover faster. And they’ve never felt better. Can they really all be deluding themselves?

As often is the case with nutrition, yes but also no. Gluten-free diets are indeed making people feel and perform better. But it likely has little to do with gluten. Instead, researchers from Australia believe they’ve found the true culprit in the form of fermentable sugar components, otherwise known as FODMAPs (fermentable oligo-di-monosaccharides and polyols, in case you were wondering). One of the most potent kinds, fructans, are poorly absorbed in the gut—and they just happen to be found in the same culprit foods that contain gluten: wheat, rye and barley.

Originally developed to help irritable bowel syndrome (IBS) patients in the late 1990s, a diet low in FODMAPs has increasingly proven itself effective in managing symptoms of the disorder, if not widely known among the general population, says Susan Shepherd, an advanced accredited practicing dietician, senior lecturer at LaTrobe University, Melbourne, and one of the original proponents of the diet.

And this is where things get interesting. “The low-FODMAP diet has also been shown to be more effective than a gluten-free diet in improving gastrointestinal symptoms in people without celiac disease,” Shepherd said.

In other words, going low-FODMAP—which, in practice, also means essentially going gluten-free—can eliminate the worst symptoms people associate with gluten intolerance: abdominal pain, bloating, gas, diarrhea, and/or constipation.

This is huge for athletes who’ve previously benefited from “gluten free,” Shepherd said. For one, by adopting a low-FODMAP diet athletes can decrease any gastrointestinal symptoms on training and competition days, which affect nearly one in seven people and up to 80 percent of athletes. For two, it can help decrease fatigue and lethargy and improve concentration. FODMAPs cause tiredness and lethargy in up to 73 percent of people.

“Achieving one and two has the potential to have a very significant positive impact on sports performance,” Shepherd said.

That’s certainly a provocative stance, but it’s gaining credibility—and attention. Dr. Peter Gibson and Jessica Biesiekierski of Monash University, Melbourne, Australia, who are often credited with starting the whole gluten-free craze are now saying FODMAPs are the more likely cause of symptoms in those who have self-reported non-celiac gluten sensitivity (NCGS).

In 2011, it was their study that provided evidence for the 1980s-proposed existence of NCGS. Another pilot study from Dr. Alessio Fasano, founder of Massachusetts General Hospital’s Center for Celiac Research, corroborated their findings. Then, the word spread rapidly that “gluten free” could improve the health of others beyond those diagnosed with celiac, a notion further popularized by low-carb and “paleo diet” followers and the publication of a few diet books. Soon enough, food marketers took notice. Mintel, a global marketing research firm, reports that the U.S. market for “gluten free” foods had 44 percent growth between 2011 and 2013 with no signs of slowing down despite only 1 percent of the population having celiac disease.

But as journalist Ross Pomeroy recently reported, Dr. Gibson and Biesiekierski performed more research that appears to have overturned initial findings. In 2013, their double-blind crossover trial evaluated gluten versus other potential dietary triggers like FODMAPs in NCGS and IBS patients that all but obliterated the conclusions of the first study. In another study published just last month, they found that one in four people who claimed they had gluten sensitivity actually had symptoms that were more likely related to FODMAPS.

That doesn’t necessarily mean that NCGS doesn’t exist at all, but that many people have misattributed their symptoms to the syndrome. There’s a major difference between the food intolerance symptoms of FODMAPs (gas and bloating) and gluten sensitivity, according to Dr. Fasano. “Comparing a reaction to FODMAPS and gluten sensitivity is like comparing apples to oranges,” he said.

Food intolerances (think: lactose or FODMAP), he explains, is caused when the body lacks the proper digestive enzymes or when they are too abundant to be fully absorbed. In contrast, a food insensitivity (think: gluten) is an immune reaction to a component in food, typically proteins, which cause both symptoms in the gut and elsewhere in the body.

“With gluten sensitivity, we are at the same point where we were with celiac disease 20 years ago. That is, we have many more questions than answers and, as our colleagues from Australia state, much more research is needed,” he said.

But for athletes and others who’ve noticed an improvement while going “gluten free,” the Australian research clearly points to what’s affecting their guts on a broader scale: FODMAPs.

Monash University has produced an app to help with avoiding high-FODMAP foods. Shepherd is also behind a new certification logo “FODMAP Friendly," which is registered internationally, including in the U.S.

Read More

Are Apples A Health Risk?

Your fruit isn’t so fresh. Take the apple. That one on your desk has likely been sitting in storage for months (tasty). So, to keep it looking fresh, it’s been treated with diphenylamine (DPA), a pesticide that doesn’t kill insects or fungal growths, but is designed to prevent fruit from developing brown or black patches.

This past March, the European Union issued what seemed, to many unaware of its proactive stance, like a very surprising statement. It would ban the importation of all apples containing the chemical, costing U.S apple growers $20 million in annual export sales. If Europe’s so worried, why aren’t we?

Introduced in 1962, DPA has been evaluated for safety several times, and subsequently deemed “unlikely to present a public health concern” by the World Health Organization. It does, however, have the potential to break down into carcinogenic nitrosamine after sitting on shelved apples for months post-harvest, according to a report by the Environmental Working Group. (Since the 1970s, the government has regulated products to prevent human exposure to nitrosamines.)

In a study by the pesticide’s manufacturers, researchers found three unknown chemicals on apples treated with DPA, but couldn’t determine whether any were nitrosamines. This unanswered question drove the European Commission to first ban DPA use on fruit grown within its own 28 member nations—and now to outlaw the import of any apples and pears containing more than 0.1 parts per million of DPA.

“Nobody has been able to identify any real risk from DPA, but Europe is trying to be on the prudent side,” says pesticide expert Carl Winter, a food toxicologist at the University of California–Davis. The Environmental Protection Agency, on the other hand, green-lights DPA residue of up to ten parts per million—a hundred times the new European standard.

But while Europe changed its stance, the Codex Committee on Pesticide Residues, and international regulatory group, hasn’t altered its regulations either, also setting them at ten parts per million. 

Both the EPA and Codex—depending on who you ask—have consistently set careful standards for the safety of chemicals. And what we end up eating often contains much lower concentrations than the standards allow. A 2011 study by Winter’s team found that our typical exposure to DPA is 208 times lower than the established acceptable level.

Of course, there’s a catch: the EPA can license a chemical that hasn’t met all the requirements—such as those for comprehensive disease-testing—on the condition that the manufacturer follows up on its data after approval. But two separate studies from the Natural Resources Defense Council (NRDC) and the Government Accountability Office found that the EPA uses this conditional registration process more often than necessary, and doesn’t always review the follow-up data, which means pesticides have been approved without confirming that they pose no real risk.

And there are factors that the EPA overlooks. It doesn’t require testing against many of the more subtle and sensitive diseases, like hormone disruption and learning disabilities (many of which have been linked to pesticide exposure). It doesn’t account for exposure to multiple pesticides at once (such as in air and water). And it often doesn’t change regulations to reflect new studies——until that ten-year review date comes up, says Jennifer Sass, a senior scientist at the NRDC.

To ever call pesticides safe is likely a misnomer. “Pesticides are literally designed to kill organisms,” Sass points out. “What the EPA regulates is safety when used according to the label, not safety against all human diseases and effects.”

Unfortunately for consumers, while there’s a handful of studies suggesting that pesticide exposure can increase the risk of birth defects, respiratory illnesses, and cancer, there are far fewer studies analyzing the effect of merely eating chemical-covered produce.

A 2011 British meta-analysis did find that organic produce has slightly more vitamins and antioxidants than chemical-covered versions (though some studies have shown otherwise), and a 2013 study in PLoS ONE revealed that fruit flies live longer when fed extracts from organic, rather than conventional, produce. But, explains Sass, exposure levels are too low, and people too diverse, for us to really test the health effects of eating organic fruit and vegetables alone.

Back to the big question: should the U.S. follow in the EU’s footsteps? Possibly. Many Americans—including the EWG—believe Europe’s decision should prompt the EPA to revisit the pesticide’s safety. But, as Winter explains, since all growers outside Europe follow the international standard of ten parts per million, doing so would have a huge impact on international trade.

Regardless of the U.S.’s actions, do keep eating those apples. “The health benefits of consuming fruits and vegetables far outweigh any potential risks from these chemicals,” says Ruth MacDonald, a registered dietitian who chairs the Food Science and Human Nutrition department at Iowa State University. If you have the financial means and the drive to buy organic, go for it—but don’t stop eating apples just because they have pesticides on them.

Read More

Putting Your Fitness Tech Data to Work

Every day, as hundreds of thousands of athletes around the world fire up their Strava apps, Nike+ FuelBands, Fitbit Flexes, and other wearable-tech devices, they produce a mind-boggling amount of data.

In 2013, Strava users recorded 53.3 million runs and rides totaling 905,408,836 miles. In the Fuel-Band’s first year on the market, Nike claims that users generated enough kinetic energy to light up more than 6,700 homes. Even bike-sharing services are amassing data. B-cycle, which runs programs in 31 cities, reports that, in 2013, its 3,813 bikes clocked 1,532,836 miles over 719,641 trips. And the International Mountain Bike Association’s (IMBA) crowdsourced trail-finder site,, contains 21,328 miles of GPS-mapped trails, with hundreds of miles of new routes being added each month.

Now that vast amount of back-end data is being used to effect real-world change. It’s already driving policy innovation: Oregon’s department of transportation has purchased Strava usage stats to improve its cycling infrastructure, right down to considering how often street cleaners should sweep bike routes in cities like Corvallis. In Arizona, IMBA tapped trail-use data to work with the Forest Service to allow bikes on several formerly illegal but well-known singletrack routes around Sedona. And the Outdoor Alliance’s exhaustive visitation stats helped federal land managers expand the 2012 Colorado Roadless Ruling from an initial 500,000 acres to 1.2 million.

But perhaps the greatest impact is happening in the health and fitness world, as researchers leverage all those bits that chronicle our routes, distances, times, and heart rates to fine-tune formulas for peak performance. Jawbone, the maker of the Up activity tracker, has found that among its thousands of users worldwide, jet lag from a coast-to-coast trip usually upsets sleep patterns for at least five days. Basis, maker of a wristwatch-style fitness and sleep tracker, is working with the University of California at San Francisco and others on sleep studies, including one that mined user info to prove that one of the most effective predictors of quality sleep is a consistent bedtime.

{%{"quote":"A vast amount of back-end data is being used to effect real-world change. And it’s already driving policy innovation."}%}

Companies are also using the data on daily habits to make concrete training prescriptions. Jawbone has found that Monday is the most popular day for workouts. (Perhaps unsurprisingly, Sunday is the least.) Strava users seem to go hardest and fastest on Wednesday, Friday, and Saturday. The takeaway? Don’t plan your high-intensity interval rides for a Thursday when, for whatever reason, the data tells us you won’t be as into it.

Colorado Springs–based Carmichael Training System regularly draws on data points culled from its work with thousands of cyclists, runners, and triathletes to guide its coaching strategies. Among the nuggets learned from years of GPS, heart-rate, and power-meter data files: Contrary to popular assumptions, mountain biking is as effective at building competition-level fitness as road riding. Those who follow its training programs closely experience fewer injuries than those who don’t. And athletes can put up maximum power numbers for as many as three consecutive days with no loss of output—despite their own perceptions that they’re losing strength.

Ten years ago, this type of data was the exclusive domain of elite athletes and a smattering of bioscience labs. “But no one looked at the data to learn from it,” says Gear Fisher, founder of TrainingPeaks, a Boulder, Colorado, online coaching platform. (TrainingPeaks’ integrative training plans are also published on Outside Online.) “They used the technology to chart real-time performance, and then they forgot about it.”

That’s why this summer, Fisher’s company is rolling out an update of its WKO+ software, which Fisher believes is one of the most accurate exercise-modeling programs ever. “We’ll be able to predict performance based on as little as one workout,” he says. The data comes from numbers collected through, which is used by thousands of coaches to manage tens of thousands of runners, triathletes, and cyclists.

Looking at all those past performances, the company will predict results for new customers. “You’ll be able to see what you’re capable of at your current level of fitness,” says Fisher, “and soon you’ll also see what you need to do to reach a specific goal, like a 13-hour finish at Ironman Florida.” That’s right—not just any Ironman, but that particular Ironman. “You may not want to do what’s required to get there,” Fisher concedes. “But we can tell you if you can.”

Looking ahead, Strava cofounder Michael Horvath sees a day when user data can help race directors design courses that challenge—but don’t destroy—participants. “We’d be able to tell how much climbing is too much from completion rates and where people quit a race,” says Horvath. He even sees it helping gear manufacturers. “Users can track the number of miles they’ve put on their running shoes before they swap in a new pair,” he says, “and from the aggregate data, we’d know how many miles runners can get from that specific model.”

The rub, of course, is that people have to actually wear the devices and upload their results. In addition, the sample size, while enormous in scientific terms, is nonetheless self-selecting: active users of wearable tech. “The best you can say about the data is that it can be used to draw useful conclusions about the people who are using each app, like Strava,” says Yuri Feito, an assistant professor of exercise science at Kennesaw State University in Maryland. Still, says Feito, “Statistically, the level of information involved with Strava dwarfs anything that a research lab could pull together on a survey of cyclists. That shouldn’t be ignored.”

Increased likelihood of achieving a fitness goal when logging training and following a plan: 100 percent.
Fitness-program success rate among participants who shared their workouts 
via social media: 
85 percent.
Extra weight lost in a month when logging an additional three days of food-diary entries: a third of a pound.
Most common cross-training exercise for runners: swimming.
Most popular activity among females in Los Angeles: hiking.
Improvement in performance when working out with a coach: 10 to 20 percent.
Average length of bike rides in 2013: 20.5 miles.
Average length of runs in 2013: 4.7 miles.
Additional sleep per night enjoyed by climbers versus other Jawbone users: 8 minutes.
Most active week in 2013 for cycling and running: August 25 to 31.

Stats from the Data Revolution:

  • Increased likelihood of achieving a fitness goal when logging training and following a plan: 100 percent. (TrainingPeaks)
  • Fitness-program success rate among participants who shared their workouts 
via social media: 
85 percent. (411Fit)
  • Extra weight lost in a month when logging an additional three days of food-diary entries: a third of a pound. (411Fit)
  • Most common cross-training exercise for runners: swimming. (Jawbone)
  • Most popular activity among females in Los Angeles: hiking. (Jawbone) 
  • Improvement in performance when working out with a coach: 10 to 20 percent. (TrainingPeaks)
  • Average length of bike rides in 2013: 20.5 miles. (Strava)
  • Average length of runs in 2013: 4.7 miles. (Strava)
  • Additional sleep per night enjoyed by climbers versus other Jawbone users: 8 minutes. (Jawbone)
  • Most active week in 2013 for cycling and running: August 25 to 31. (Strava)

Read More

Free Newsletters

Dispatch This week's featured articles, reviews, and videos. Sent twice weekly.
News From the Field The most important breaking news from around the Web. Sent daily.
Outside GOOur hottest adventure-travel tips and trips. Sent occasionally.
Outside Partners Outside-approved deals and special offers from select partners. Sent occasionally.

to Outside
Save Over

Magazine Cover

iPad Outside+ App Access Now Included!







Previous Posts




Blog Roll

Current Issue Outside Magazine

Subscribe and get a great deal! Two free Buyer's Guides plus a free GoLite Sport Bottle. Monthly delivery of Outside—your ultimate resource for today's active lifestyle. All that and big savings!

Free Newsletters

Dispatch This week's featured articles, reviews, and videos. Sent twice weekly.
News From the Field The most important breaking news from around the Web. Sent daily.
Gear of the Day The latest products, reviews, and editors' picks. Coming soon.
Outside Partners Outside-approved deals and special offers from select partners. Sent occasionally.

Ask a Question

Our gear experts await your outdoor-gear-related questions. Go ahead, ask them anything.

* We might edit your question for length or clarity. If it's not about gear, we'll just ignore it.