10,000 hours, plus or minus 10,000 hours

Saturday, May 1st, 2021

In The Sports Gene David Epstein tells a tale of two high jumpers.

Stefan Holm was inspired by the 1980 Moscow Olympics, which he watched on TV as a four-year-old in his native Sweden, to jump over the sofa. He broke his arm but was undeterred. When he was six, his father built a high-jump pit in their backyard out of pillows and an old mattress. He became obsessed with the sport. At 15, he won the Swedish youth championships.

But Holm was just 5’11″, not 6’7″, like his idol Patrik Sjöberg. To compensate, he developed a sprinting approach and started taking off from farther and farther away from the bar.

In 1998, he won the first of eleven consecutive Swedish national championships. He trained 12 sessions per week.

Without a running start, Holm’s standing vertical jump hovered around twenty-eight inches, which is perfectly pedestrian for an athlete. But his blazing fast approach allowed him to slam down on his Achilles tendon, which would then act like a rebounding spring to propel him over the bar. When scientists examined Holm, they determined that his left Achilles tendon had hardened so much from his workout regimen that a force of 1.8 tons was needed to stretch it a single centimeter, about four times the stiffness of an average man’s Achilles, making it an unusually powerful launching mechanism.

In 2005, a year after he won the Olympic title, Holm earned a qualification of the perfect human projectile: he cleared 7’10.5″, equaling the record for the highest high-jump differential between the bar and the jumper’s own height.

In 2007 he entered the World Championships in Osaka, Japan, as the favorite, and was facing a competitor he barely knew, Donald Thomas, from the Bahamas. Thomas had just begun high jumping, in the U.S. A friend at college had dared him to high-jump a 6’6″ bar, and he did. Then he cleared 6’8″. Then he cleared 7 feet. So they told the track coach:

Two days later, in a black tank top and white Nike sneakers and shorts so baggy they blanketed the bar as he passed over it, Thomas cleared 6’8.25″ on his first attempt, qualifying for the national championships. Then he cleared 7’0.25″ for a new Lindenwood University record. And then, on the seventh high jump attempt of his life, with rigid form akin to a man riding an invisible deck chair backward through the air, Thomas cleared 7’3.25″, a Lantz Indoor Fieldhouse record. That’s when Coach Lohr forced him to stop out of concern that he might hurt himself.

[...]

In his first full season, Thomas cleared 7’7.75″ to win the NCAA indoor high jump championship.

Thomas won the 2007 world championship.

The advice to “keep your eye on the ball” is literally impossible

Monday, March 8th, 2021

When David Epstein’s The Sports Gene: Inside the Science of Extraordinary Athletic Performance came out, I bought it in hardcover and enjoyed it immensely — but physical books don’t lend themselves to blogging. So, when I saw that the Kindle edition was on sale for $1.99, I “picked up” a copy and reread it.

The opening chapter explains how the Pepsi All-Star Softball Game was contested by Major League Baseball players — until one year, when they brought in a true softball pitcher from Team USA, Jennie Fitch:

As part of the pregame festivities, a raft of major league stars had tested their skill against Finch’s underhand rockets. Thrown from a mound forty-three feet away, and traveling at speeds in the upper-60-mph range, Finch’s pitches take about the same time to reach home plate as a 95-mph fastball does from the standard baseball mound, sixty feet and six inches away. A 95-mph pitch is fast, certainly, but routine for pro baseball players. Plus, the softball is larger, which should make for easier contact.

Nonetheless, with each windmill arc of her arm, Finch blew pitches by the bemused men.

For four decades, scientists have been constructing a picture of how elite athletes intercept speeding objects.

The intuitive explanation is that the Albert Pujolses and Roger Federers of the world simply have the genetic gift of quicker reflexes that provide them with more time to react to the ball. Except, that isn’t true.

[...]

A typical major league fastball travels around ten feet in just the 75 milliseconds that it takes for sensory cells in the retina simply to confirm that a baseball is in view and for information about the flight path and velocity of the ball to be relayed to the brain. The entire flight of the baseball from the pitcher’s hand to the plate takes just 400 milliseconds. And because it takes half that time merely to initiate muscular action, a major league batter has to know where he is swinging shortly after the ball has left the pitcher’s hand, well before it’s even halfway to the plate.

The window for actually making contact with the ball, when it is in reach of the bat, is 5 milliseconds, and because the angular position of the ball relative to the hitter’s eye changes so rapidly as it gets closer to the plate, the advice to “keep your eye on the ball” is literally impossible. Humans don’t have a visual system fast enough to track the ball all the way in.

[...]

So why are [All-Star batters] transmogrified into Little Leaguers when faced with 68-mph softballs? It’s because the only way to hit a ball traveling at high speed is to be able to see into the future, and when a baseball player faces a softball pitcher, he is stripped of his crystal ball.

Hurtling to the earth in a free fall is something you can get acclimated to

Sunday, March 7th, 2021

Top Dog: The Science of Winning and Losing opens with a study of first-time skydivers:

Analyzing the jumpers’ saliva samples, Deinzer wasn’t surprised to learn that they had a huge rush response to the first jump. But with each subsequent jump, the rush was reduced by about a quarter. By just the third jump, there was still a pronounced rush of stress, but (on average) it was now only half the first jump’s intensity. It was more akin to the stress you get from driving in slow traffic that’s making you late.

Apparently, hurtling to the earth in a free fall is something you can get acclimated to, rather quickly.

[...]

Stephen Lyng is a scholar who studies edgework, a term borrowed from Hunter S. Thompson’s description of anarchic human experiences. During the 1980s, Lyng was a jump-pilot at a local skydiving center. He contrasted what he learned there from skydivers with what he learned later by studying car racers, downhill skiers, combat soldiers, and business entrepreneurs. Lyng eventually concluded that the true “high” of skydiving, and other edgework, stems from the way skilled performance brings control to a situation most people would regard as uncontrollable.

All of the safety rituals used to minimize the danger (in situations of extreme risk) engender this sense of control, but edgeworkers’ fundamental skills are the ability to avoid being paralyzed by fear and the capacity to focus their attention on the actions necessary for survival. The feeling of self-determination they get from conquering the risks is the real payoff. It’s not pure thrill they seek, but the ability to control the environment within a thrilling context.

How does this compare to ballroom dancing — in the Nordrhein-Westfalen Regional Ballroom Dance Competition?

The pressure of ballroom dancing induced a stress rush just as strong as someone’s second parachute jump. Many of the ballroom dancers’ stress response was every bit as high as a first parachute jump.

Don’t forget — this was not the dancers’ first competition, or second. On average, the competitors had been in 131 competitions, and they had been going to dance contests for eight years. Yet even with all that experience competing, plus thousands of hours of practice, ballroom dancing was still enormously stressful.

[...]

According to what science tells us, dancing at that point in their lives should have required very little cognitive control. All the muscle memory should have been driven down into the cerebellum region of their brains, where it was automated. There should have been no worry over forgetting to vary the inside and outside of their feet to create style and line.

[...]

The cutthroat world of the ballroom remained terrifying no matter how long they’d been at it. The contestants did not habituate.

[...]

How is it that someone can immediately get used to skydiving but can never get used to ballroom dancing?

[...]

The real difference was the psychological environment. The expert dancers were in a competition, and the novice parachutists were not. To be more precise, it wasn’t the dancing that was stress-inducing. It was being judged. It was winning and losing.

[...]

Ten years of practice may make you an expert. But even then, it just gets you in the door. You’ll still have to dance against other experts — most of whom have put in their ten years, too.

[...]

The same fundamental skills that matter in edgework turn out to matter in any competitive situation: the ability to avoid being paralyzed by fear, and the capacity to focus attention.

(I bought the Kindle edition on sale for $1.99, and it’s still on sale.)

Glucosamine may reduce overall death rates as effectively as regular exercise

Tuesday, January 5th, 2021

Glucosamine may reduce overall death rates as effectively as regular exercise:

[Dana King, professor and chair of the Department of Family Medicine at West Virginia University] and his research partner, Jun Xiang — a WVU health data analyst — assessed data from 16,686 adults who completed the National Health and Nutrition Examination Survey from 1999 to 2010. All of the participants were at least 40 years old. King and Xiang merged these data with 2015 mortality figures.

After controlling for various factors — such as participants’ age, sex, smoking status and activity level — the researchers found that taking glucosamine/chondroitin every day for a year or longer was associated with a 39 percent reduction in all-cause mortality.

It was also linked to a 65 percent reduction in cardiovascular-related deaths. That’s a category that includes deaths from stroke, coronary artery disease and heart disease, the United States’ biggest killer.

“Once we took everything into account, the impact was pretty significant,” King said.

The results appear in the Journal of the American Board of Family Medicine.

Mighty Mice in Space

Friday, September 18th, 2020

A research team led by Dr. Se-Jin Lee of the Jackson Laboratory in Connecticut sent 40 young female black mice to the International Space Station in December, to study muscle loss:

In a paper published in the Proceedings of the National Academy of Sciences, Lee said the 24 regular untreated mice lost considerable muscle and bone mass in weightlessness as expected — up to 18%. But the eight genetically engineered “mighty mice” launched with double the muscle maintained their bulk. Their muscles appeared to be comparable to similar “mighty mice” that stayed behind at NASA’s Kennedy Space Center.

The PNAS abstract explains:

Among the physiological consequences of extended spaceflight are loss of skeletal muscle and bone mass. One signaling pathway that plays an important role in maintaining muscle and bone homeostasis is that regulated by the secreted signaling proteins, myostatin (MSTN) and activin A.

Here, we used both genetic and pharmacological approaches to investigate the effect of targeting MSTN/activin A signaling in mice that were sent to the International Space Station.

Wild type mice lost significant muscle and bone mass during the 33 d spent in microgravity. Muscle weights of Mstn -/- mice, which are about twice those of wild type mice, were largely maintained during spaceflight.

Systemic inhibition of MSTN/activin A signaling using a soluble form of the activin type IIB receptor (ACVR2B), which can bind each of these ligands, led to dramatic increases in both muscle and bone mass, with effects being comparable in ground and flight mice.

It’s not just mice who have muscle-building myostatin-related mutations, but Belgian Blue cattle, Flex Wheeler, a German toddler, a Michigan toddler, and “bully” whippets.

Trans men should be allowed to play against biological men

Sunday, July 26th, 2020

World Rugby is considering banning trans women from playing women’s rugby because of significant safety concerns that have emerged following recent research:

The Guardian can reveal that in a 38-page draft document produced by its transgender working group, it is acknowledged that there is likely to be “at least a 20-30% greater risk” of injury when a female player is tackled by someone who has gone through male puberty. The document also says the latest science shows that trans women retain “significant” physical advantages over biological women even after they take medication to lower their testosterone.

As a result, World Rugby’s working group suggests that its current rules, which allow trans women to play women’s rugby if they lower their testosterone levels for at least 12 months in line with the International Olympic Committee’s guidelines, are “not fit for the purpose”.

[...]

It also recommends that trans men should be allowed to play against biological men, provided they have undergone a physical assessment and have signed a consent form.

[...]

As World Rugby’s working group notes, players who are assigned male at birth and whose puberty and development is influenced by androgens/testosterone “are stronger by 25%-50%, are 30% more powerful, 40% heavier, and about 15% faster than players who are assigned female at birth (who do not experience an androgen-influenced development).”

Heat is the poor man’s altitude

Sunday, July 12th, 2020

This is the time of year, Alex Hutchinson reminds us, when fitness journalists write articles about how the miserable heat that’s ruining your workouts is actually doing you a big favor:

You’re lucky to be dripping buckets of sweat and chafing up a storm, because heat is the “poor man’s altitude,” ramping up the physiological demands of your workout and triggering a series of adaptations that enhance your endurance.

[...]

Heat training works differently [from altitude training]. The most notable change, after just a few days, is a dramatic increase—of up to 20 percent—in the volume of plasma coursing through your veins. That’s the part of the blood that doesn’t include hemoglobin-rich red blood cells, so it’s not immediately obvious whether more plasma will enhance your endurance under moderate weather conditions.

[...]

If heat training causes your plasma volume to increase, that will lower your hematocrit.

Lundby’s hypothesis is based on the idea that your kidneys are constantly monitoring hematocrit, trying to keep it in a normal range. If your hematocrit has a sustained decrease, the kidney responds by producing EPO to trigger the production of more hemoglobin-rich red blood cells. Unlike the rapid increase in plasma volume, this is a slower process. Lundby and his colleagues figure it could take about five weeks.

[...]

The 11 cyclists in the heat group did those sessions in about 100 degrees and 65 percent humidity; the 12 cyclists in the control group did the same sessions at 60 degrees and 25 percent humidity, aiming for the same subjective effort level. During the heat sessions, the cyclists were limited to half a liter of water to ensure mild dehydration, which is thought to be one of the triggers for plasma volume expansion.

The key outcome measure: total hemoglobin mass increased 893 to 935 grams in the heat group, a significant 4.7 percent increase. In the control group, hemoglobin mass stayed essentially unchanged, edging up by just 0.5 percent.

Only you can figure out what your stomach can tolerate

Sunday, June 14th, 2020

As Patrick Wilson points out in his new book The Athlete’s Gut: The Inside Science of Digestion, Nutrition, and Stomach Distress, the path to a happy gut is nuanced and context specific:

One study found that roughly 70 per cent of athletes experience at least one severe side stitch in a given year. Another study found that 40 per cent of marathoners get an uncomfortable urge to defecate during hard runs. “It’s fair to say,” Wilson writes, “that most athletes occasionally experience gut problems during training or competition.”

There are several reasons for this, but perhaps the most important is that your muscles demand oxygen-rich blood during exercise, which diverts blood away from the gut. The oxygen-starved digestive organs then struggle to deal with whatever partially digested food remains there.

For that reason, hard exercise is a more potent trigger than easy exercise. Activities with lots of jostling, such as running and horseback riding, increase your risk. Women report more gut problems than men, for reasons that aren’t understood. The bottom line: Most symptoms have more than one contributing factor, which means you’ll need to experiment with several possible countermeasures.

[...]

Is it the lactose that’s messing up your workout? For a few people, yes; for most people, no. Same goes for the gluten, the fructose, the fibre, the too-big or too-small meals, the underdrinking or overdrinking. Only you can figure out what your stomach can tolerate.

But once you figure it out, you can change it. Just like your muscles, your digestive tract adapts to the stresses you put on it. If you carb load, your intestine will develop more transporters to ferry those carbohydrates into your bloodstream more quickly. If you practise drinking on the run, your stomach will adapt to feel less full with a bellyful of liquid.

Heat is now hot

Saturday, June 13th, 2020

Heat is now hot, in the world of athletic training:

Maybe the sauna-loving Finns — who, in addition to topping the rankings in this year’s World Happiness Report, have racked up more than 100 Olympic track and field medals — have been onto something all along.

The origins of the current boom in heat research can be traced back to the 2008 Olympics. University of Oregon physiologist Chris Minson was helping marathoner Dathan Ritzenhein prepare for what was expected to be a sweltering summer in Beijing. Heat-acclimation protocols, which usually involve a week or two of sweaty workouts, are a well-established way of triggering adaptations — increased blood-plasma volume, lower core temperature, higher perspiration rate — that help you perform in the heat. “But I had this niggling fear,” Minson recalls. “What if the race wasn’t hot? What if it was cooler?”

No one knew for sure whether being well-adapted to heat might come with trade-offs, like performing worse in cool conditions. So Minson set up a study with 20 cyclists to find out. The results, published in 2010, sparked a frenzy among sports scientists. Ten days of training in 104-degree heat boosted the cyclists’ VO2 max by 5 percent and improved their one-hour time-trial performance by 6 percent — even when the testing room was kept at a brisk 55 degrees. Suddenly, hot rooms and nonbreathable track suits were being hyped as the poor man’s altitude training.

The initial thinking was that, whereas working out in thin air triggers the formation of oxygen-carrying red blood cells, a main benefit of heat training was an increased volume of blood plasma to ferry red blood cells to your muscles. Whether that plasma boost actually translates to improved athletic performance remains contentious. Carsten Lundby, an endurance expert at Copenhagen University Hospital in Denmark who has studied heat training, is skeptical that simply increasing plasma volume improves performance after just a week or two. However, the resulting dilution of your blood might trigger a natural EPO response to produce new red blood cells, just like altitude training — an idea he’s currently testing with a six-week protocol.

But plasma volume isn’t the only parameter that heat changes. According to Meylan, psychological resilience and altered perception of high temperatures are among the key benefits his players received from heat training. That, in part, is why Canada’s women’s soccer team will likely head to southern Spain or Portugal right before next summer’s World Cup, which will take place in France.

More generally, heat is a shock to the system, generating some of the same cellular responses that exercise and altitude do. For that reason, scientists are now studying its therapeutic benefits, as well as cross-adaptation, the idea that heat training might prepare you for a trip to high elevations, or help you maintain an edge when you return.

A practical example: Last year, three elite steeplechasers visited Minson’s lab three or four times a week to soak in a 105-degree hot tub for roughly 40 minutes, hoping the heat would help sustain the elevated red-blood-cell levels they’d developed during altitude training in Flagstaff, Arizona. Blood tests suggested the approach worked.

We can now estimate the effect of blood doping

Wednesday, May 13th, 2020

We can now estimate the effect of blood doping, Alex Hutchinson notes, following the introduction of the Athlete Biological Passport in 2012:

The design of the study was straightforward. Iljukov and his colleagues looked at the top eight times from the Russian National Championships between 2008 and 2017 in the women’s 800, 1,500, 3,000 steeplechase, 5,000, and 10,000-meters. Anti-doping authorities started collecting longitudinal data to assemble biological passports in 2009, and began formally using the technique and applying sanctions sometime around 2011. Figuring that the deterrent effect of the ABP program started after the first bans were handed out, the researchers divided the results into two categories: 2008 to 2012, and 2013 to 2017.

There are a few different ways you can slice and dice the data, and the researchers also looked at other metrics like the number of athletes caught doping in these events and the number of Russian women hitting the Olympic qualifying standard. But the simplest outcome is the average of those top-eight times before and after the ABP. Here’s what that looks like for each of the five events analyzed:

doping-test-blood_h_0

For four of the five events, there’s a significant slowdown, ranging between 1.9 percent in the 800 and 3.4 percent in the 5,000. The only exception is the steeplechase, which was still a relatively new event for women in 2008, when it made its first appearance at the Olympics. The steeplechase also involves hurdling over barriers, which introduces an additional performance variable beyond pure endurance capacity.

One way of interpreting these findings, Iljukov says, is to conclude that for elite athletes, “a significant amount of blood transfusion could improve running times by 1 to 4 percent, depending on the distance, but on average 2 to 3 percent.” The paper compares this estimate with early studies of blood doping in elite athletes, including some old Soviet studies that don’t show up in the usual PubMed searches, which support the idea of a 1 to 4 percent range of improvement from a transfusion of 750 to 1,200 milliliters of blood.

These days, the ABP program makes it difficult to get away with adding that much blood to your system. Instead, would-be cheaters are limited to microdosing with small amounts of blood. Iljukov guesses that this might still give a one-second edge to an elite 800-meter runner—far from fair, but much better than the previous situation. Of course, this deterrent only works if the athletes in question are being regularly tested to generate sufficient data for a biological passport.

Serious endurance training makes sitting sort of OK

Monday, May 11th, 2020

There are a bunch of different theories about what makes prolonged sitting so bad, Alex Hutchinson notes, but one of them relates to the associated reduction in blood flow in your legs:

Your blood vessels sense the frictional drag of blood rushing past the vessel walls, and respond by producing molecules such as nitric oxide that help keep the vessels supple and responsive. If you spend too much time sitting, this signal is reduced, and you end up with blood vessels that are stiffer and less capable of dilating and contracting in response to changes in blood flow. Over time, that leaves you more likely to develop atherosclerosis, a hardening and narrowing of the arteries, and ultimately heart disease.

You can test how responsive your blood vessels are with a technique called flow-mediated dilation. Basically, you temporarily restrict blood flow with an inflatable cuff like the ones doctors use to measure your blood pressure, then release the cuff and see how much the vessels dilate in response. If you take this measurement before and after a three-hour bout of sitting, you find that the amount of dilation is dramatically reduced after sitting—a bad sign for the health of your arteries.

That’s the protocol used in the new study, which compared 10 male cyclists from the university’s racing team with matched controls who didn’t do any regular endurance training. The graph below shows the percentage increase in blood flow through the lower leg’s popliteal artery when the cuff is released. On the left, you can see that even before sitting, the trained cyclists (black) have a somewhat bigger response than the control group (white), which is expected since endurance training enhances baseline levels of nitric oxide. But the starkest difference, on the right, emerges after three hours of sitting.

sitting-arteries-health_h

The bout of sitting almost wipes out the flow-mediated dilation response in the control group, but it barely changes in the cyclists. Hooray! I can leave my desk in the sitting position for another hour!

Being able to quick draw is probably the number-one skill in this sport

Sunday, March 15th, 2020

John Jackson is credited with founding the sport of archery dodgeball in 2011:

Also known as combat archery and archery tag, it’s grown to more than 1,300 locations throughout the U.S.

Rules differ state to state, but essentially when a referee blows a whistle, teams rush to a central dividing line, grab as many arrows as possible and attempt to hit their opponents while simultaneously dodging incoming fire. Unlike dodgeball, players can shield themselves behind inflatable obstacles. If players are hit, they’re eliminated and move to their team’s sideline. If they catch an arrow, the shooter is out and a sidelined teammate can return.

“At a distance, you can catch or dodge an arrow, but at close range you’re getting hit,” Mr. Reckner says. “The speed and force is comparable to a dodgeball thrown by an adult who is pretty good at dodgeball.”

The arrows are foam tipped:

Games consist of seven rounds, each of which may have different rules. For example, each team may have a target resembling a domino, with foam circles as dots. If a player shoots a foam circle out of the opposing target, an eliminated player on the shooter’s team can return to play. The round ends when one team has all players eliminated.

“It’s easy to think the most accurate shot wins, but really the game is more about being quick on your feet, being fast with the bow and having solid cardio conditioning,” Mr. Reckner says. The Cincy Aimbots have won a round in as little as 30 seconds, but Mr. Reckner says some last over five minutes. “Getting gassed in the middle of a round makes you an easy target,” he says.

Mr. Reckner started watching YouTube videos of Danish archer Lars Andersen:

To build speed, he lines up five arrows on the ground and attempts to pick up, load and fire all five within 10 seconds. “Being able to quick draw is probably the number-one skill in this sport,” he says. He repeats the drill 10 to 20 times. To build muscle memory, he loads an arrow on the bowstring and draws it back 25 to 50 times as quickly as possible.

Mr. Reckner says being able to hold an extra arrow is very useful—you become vulnerable when you attempt to grab an arrow from the gym floor. To build grip strength, he practices shooting while holding an extra arrow or two in his left hand. He also keeps three grip trainers of varying resistances in his living room. While watching TV, he’ll do three sets of 10 reps with each grip trainer. “I don’t have the biggest hands, so a strong grip helps me hold a bow and extra arrows,” he says.

He rides his Peloton bike four to five days a week, simulating hill climbs to build leg strength. “There is a lot of squatting during the matches, to either hide behind a low barrier or to pick up an arrow from the arena floor,” he says. He isn’t as committed to his strength routine and says he only uses his home gym one to two days a week, performing dead lifts, squats, bench presses and overhead presses.

Trekkers with the biggest lungs, the biggest spleens, and the biggest reduction in heart rate during a breath-hold were the least likely to develop symptoms of acute mountain sickness

Sunday, March 8th, 2020

Ever since reading James Nestor’s 2014 book Deep, Alex Hutchinson has been fascinated by the scarcely believable feats of freedivers:

Plunging 335 feet below the surface of the ocean and making it back on a single breath, or simply holding your breath for 11 minutes and 35 seconds, clearly requires a very special set of skills and traits.

But until a recent conference talk, I’d never considered whether those same characteristics might be useful in other settings where oxygen is scarce — such as the thin air of high-altitude trekking and mountaineering.

[...]

Schagatay’s initial research interest was in what she calls “professional” freedivers, as opposed to recreational or competitive freedivers.

[...]

These diving populations, Schagatay and others have found, share three distinctive characteristics with successful competitive freedivers, who take part in contests around the world sanctioned by AIDA, the international freediving authority:

Big lungs: In one study of 14 world championship freedivers, vital capacity — the maximal amount of air you can expel from your lungs — was correlated with their competition scores. The three best divers in the group had an average vital capacity of 7.9 liters, while the three worst averaged just 6.7 liters. And it’s not just genetic: Schagatay found that an 11-week program of stretching increased lung volume by nearly half a liter.

Lots of red blood cells: Divers do tend to have higher levels of hemoglobin, the component of red blood cells that carries oxygen. That’s probably a direct result of their diving. Even if you just do a series of 15 breath holds, you’ll have a surge of natural EPO an hour later, which triggers red blood cell formation.

But there’s a more direct and immediate way of boosting your red blood cell count: squeezing your spleen, which can store about 300 milliliters of concentrated red blood cells. Seals, who are among the animal kingdom’s most impressive divers, actually store about half their red blood cells in their spleens, so they don’t waste energy pumping all that extra blood around when it’s not needed. When you hold your breath (or even just do a hard workout), your spleen contracts and sends extra oxygen-rich blood into circulation. Not surprisingly, spleen size is correlated with freediving performance.

A robust “mammalian diving response”: When you hold your breath, your heart rate drops by about 10 percent, on average. Submerge your face in water, and it will drop by about 20 percent. Your peripheral blood vessels will also constrict, shunting precious oxygen to the brain and heart. Together, these oxygen-conserving reflexes are known as the mammalian diving response — and once again, the strength of this response is correlated with competitive diving performance.

[...]

In a study published last year, they followed 18 trekkers to Everest Base Camp at 17,500 feet (5,360 meters). Sure enough, the trekkers with the biggest lungs, the biggest spleens, and the biggest reduction in heart rate during a breath-hold were the least likely to develop symptoms of acute mountain sickness.

The size of the spleen isn’t the only thing that matters — its benefits depend on a strong squeezing response to get all the red blood cells out. In a 2014 study of eight Everest summiters, they found that three repeated breath holds prior to the ascent caused spleen volume to squeeze, on average, from 213 milliliters to 184 milliliters. After the ascent, the same three breath holds caused the spleen to squeeze down to 132 milliliters. Prolonged exposure to altitude had strengthened the spleen’s diving response. In fact, there’s also evidence that simply arriving at moderate altitude will cause a sustained mild spleen contraction, as your body struggles to cope with the oxygen-poor air.

Getting there six days early helps

Wednesday, March 4th, 2020

There are no shortcuts to feeling good at altitude, Alex Hutchinson (Endure) finds, as he summarizes a recent study:

One of the most pressing questions for people slotting mountain adventures into precious vacation is how much time they need to allot to acclimatization. Will arriving a day or two early make an appreciable difference to their performance and health? This is also, as it turns out, a crucial question for military personnel being deployed on mountain missions where they need to quite literally hit the ground running. Optimizing that calculation is the motivation for a new study from researchers led by Robert Kenefick at the U.S. Army Research Institute of Environmental Medicine, in Natick, Massachusetts, published in the journal Medicine & Science in Sports & Exercise.

The question the new study asks is: if you’re headed to 14,000 feet (4,300 meters) and need to perform well right away, is it worth trying to get there (or partway there) two days early? Specifically, the researchers had 66 volunteers complete a series of tests, including a 5-mile time trial on a treadmill set at 3 percent grade, at the altitude research lab on the summit of Pikes Peak in Colorado. For the two days prior to the tests, the subjects were split into four groups who either camped in Pikes Peak National Forest at 8,200 feet, 9,800 feet, or 11,500 feet, or stayed at the research station at 14,000 feet. A previous study from the same group had found that spending six days at 7,200 feet did significantly improve performance after a rapid ascent to 14,000 feet, an approach known as staging. But who’s got six extra vacation days? The goal this time was to do it faster by going higher.

There was one other variable the researchers threw in. Exercising at altitude puts your oxygen-starved body in even greater stress, so adding some workouts during your acclimatization period might serve as an additional adaptive stimulus.

[...]

The result of all these machinations? A big fat nothing. All eight of the subgroups produced essentially identical results in the final testing at 14,000 feet.

[...]

But if we have to extract some general rules of thumb for mountain adventures from this body of research, I’d go with: getting there six days early helps; getting there two days early doesn’t; and, since we don’t yet know what happens between days two and six, you should err on the safe side and lobby for more vacation days.

Does owning a car hurt your health?

Thursday, February 20th, 2020

Does owning a car hurt your health? To really answer that, you’d need a randomized trial:

But who’s going to assign long-term car ownership on the basis of a coin flip?

The city of Beijing, it turns out. Because of mounting congestion, Beijing has limited the number of new car permits it issues to 240,000 a year since 2011. Those permits are issued in a monthly lottery with more than 50 losers for every winner – and that, as researchers from the University of California Berkeley, Renmin University in China and the Beijing Transport Institute recently reported in the British Medical Journal, provides an elegant natural experiment on the health effects of car ownership.

Led by Berkeley economist Michael Anderson, the researchers followed 180 permit winners and 757 losers for roughly five years, and looked for differences caused by the acquisition of a car.

“The randomization of the lottery is what gives us confidence,” Anderson explained in a statement. “We know that the winners should be comparable to the losers on all attributes other than car ownership.”

Not surprisingly, the winners took 2.9 fewer rides a week on Beijing’s dense public-transit network, representing a 45-per-cent drop in usage. They also spent 24.2 fewer minutes each day day walking or biking than the non-winners, a 54-per-cent drop.

You’d expect these behaviour changes to have health impacts. Over all, the winners gained an average of just more than two kilograms, a difference that was not statistically significant. But the effects were more obvious when looking only at winners aged 50 or older: They gained an average of 10.3 kilograms, a statistically significant and worrisome increase.