Running, by the numbers

Data and running and charts about racing...
... these are a few of my favorite things!
(Sung as though this were The Sound of Music)

Key findings:

• Either we're racing more, or there are more of us: Road racing finishers increased by 170% between 1991 and 2011 at a time when the U.S. population grew by only 20%.
• Despite early sell-out (or maybe because of it?) the number of marathons in the U.S. more than doubled between 2000 and 2011.
• There were more than 50,000 ultra-marathon finishers in 2011, but that still pales in comparison to the more than 500,000 marathon finishers.

Thanks to the Running Moron for the link, and RunningShoes.com for the infographic.

Running will kill you (or not) - and a stats lesson

One death in the ultra-running community, and suddenly there's a flurry of news headlines touting research that "running is bad for you." Recent publications from the Mayo Clinic Proceedings and American Journal of Cardiology show that endurance athletes have higher rates of atrial fibrillation (irregular heartbeat) than non-runners and moderate exercisers.

But there is plenty of well-documented, conflicting evidence that running is linked to longer life expectancy. And isn't obesity killing us? (Or maybe high BMI isn't so bad if you exercise, too.)

Is your head spinning yet?

Image source

What's a runner to believe?

Allow me to switch hats to my "day job" for a moment, wherein I get paid to play with data and write articles about correlation...

My advice:
Believe none of the headlines.
Not the good stuff or the bad stuff.
And here's why...

First:
Each of the headline-grabber articles shows correlation, not causality.

Correlation is a purely statistical relationship. For example: ice cream consumption and bicycle accidents rise and fall at about the same time of year.

Image source

Causality is the reason why those things vary together. Clearly, from our example, ice cream doesn't cause more bike accidents; long, hot summer days are to blame for both.

The best analysis will try to show both correlation and causality. Unfortunately, in the messy realm of real-world statistics, that's often easier said than done.

To be fair, the 2008 study did attempt to identify exercise as the cause for lower disability and higher life expectancy among runners by controlling for factors including age, sex, body mass index, smoking, and disability level. But maybe the investigators failed to capture some key explanatory variable like the "running buddy effect?" After all, research does show a positive correlation between social networks and health.

And in the new studies that show higher rates of heart malfunction among endurance athletes, maybe the analysis fails to account for those with extremely low body weight? Research shows that both "underweight" (low BMI) and obesity are correlated with higher mortality than "normal" weight. Or maybe ultra-runners are more likely to eat a certain type of food, or are more likely to go through bouts of dehydration...?

The point is that no study can control for all factors.

In fact, the American Journal of Cardiology article even admits to this weakness:

"Recent studies have shown that the prevalence of AF [atrial fibrillation] is higher in individuals who are involved in intense short-term training and long-term sports participation compared to general population of the same age although clear evidence about the causal relation between these conditions is lacking." (emphasis added)

To look at the importance of understanding both correlation and causality, let's take a step back and consider alcohol.

We've all heard that moderate alcohol consumption is "good for our health," right?

Well... it's not that simple.

The alcohol/health correlation is based on the U-shaped "mortality risk" curve shown below. In this case, much like with golf scores, a lower number is better because it means less likelihood of dying at any given point in time.

Those who drink 0 drinks per day (left side of chart) have a higher mortality risk (i.e. are more likely to kick the bucket) than those who drink, say, 20 grams (slightly more than 1 drink) per day. After that first drink, risk of death starts going up. (By the far right hand side of the chart we're drinking ourselves into instant liver failure.)

Image source

The data clearly show that moderate alcohol consumption is correlated with lower "mortality risk."

So pour me a beer, right?

Not so fast.
We've forgotten about that little problem of causality.

When we stop to think about the "reasons" - the causal factors - that make those abstainers avoid alcohol, a few causes stand out:

• People who are non-drinkers might abstain because they have another health problem (think of prescription labels that warn about adverse drug interactions with alcohol).
• Non-drinkers may have been problem drinkers in the past (thus the damage may already be done).
• And last, but not least, people who are moderate drinkers probably are drinking with friends (again with that pesky "friend" benefit).

Once researchers controlled for those other factors (especially that doosie in the first bullet point - the underlying health conditions) the curve shifted. Mortality risk is higher for every gram of alcohol consumed per day.

Moderate alcohol consumption isn't the cause of better health, it's a symptom of it!

When we look at statistics, we must keep in mind both the correlation and the causal factors. The statistical relationship is important, but the reason for the relationship is more important.

Second:
(You thought I was done? Well, almost...)
Even if there was a proven link between exercise and longer (or shorter) life there will still be a sizeable minority of the population that bucks the trend.

Image source

Correlation predicts average results.
Some of us are a-typical.
Outliers.
Extreme cases.

And (unfortunately) we have no idea who is typical and who is unique until we test the theory in that great "experiment of one."

The moral of this story:
Talk to your doctor.
Listen to your body.
Read the literature, but do so with a critical eye.

(And if you don't believe me, try Amby Burfoot and George Sheehan's take on the conflicting headlines.)

New York runners' favorite routes

In my day job, I'm a data geek who drools over clever new visualization techniques. I should have a bumper sticker that says "I *heart* infographics" alongside my "13.1" and "I run like a girl, try to keep up."

Fortunately I'm not alone in my neurosis passion. And occasionally my two obsessions come together nicely. Case in point:

Have you ever wondered what happens to all of the data collected by Nike+ technology? Well... the clever folks and YesYesNo and Design Forces teamed up to create an on-map visualization of all of the runs Nike+ users did in Manhattan in a year.

Image source

The thicker the line, the more users were on that route. (Go figure, Central Park gets a lot of action.) To learn more about the project, click here, or watch the video:

What's your take on this type of personal data collection an analysis: amazing analytic tool or big brother?

Empire state of mind -- NYC Marathon stats

In my other life, I am a big, fat STATS GEEK. So, honor of the ING New York City Marathon, here are some eye-opening stats about the race (and some Jay-Z and Alicia Keys, just because):

Who's running:

Today the race is more than 350 times larger than it was the first year. In 1970, according to the organizers of the marathon, "127 runners paid the $1 entry fee to NYRR to participate in a 26.2-mile race... Fifty-five runners crossed the finish line." On Sunday officials expect 45,000 runners to toe the starting line. To put that in perspective, there will be one NYC Marathon runner for every resident of Olympia, WA (or Harrisburg, PA - for those in the eastern time zone).
Of those 45,000 runners:

• 62% men / 38% women (similar to nationwide stats which showed a 59/41 split for male/female marathon finishers in 2010)
• One third are between the ages of 40 and 49.
• The oldest male entrant is 87. The oldest female is 84.

Who's making it happen:

• More than 150 New York Road Runners staff work year-round on the marathon.
• There are more than 8,000 volunteers for the event.
• The week before the race, 100 people worked to clean up the post-snowstorm debris in Central Park that was blocking the race course.

Hydration and fuel:
According to Wolfram|Alpha "to help energize and hydrate the runners before the race begins" organizers will provide runners with:

• 42,000 Power Bars
• 90,000 bottles of water
• 45,000 cups of coffee

On the course, there will be:

• 62,370 gallons of water
• 32,040 gallons of Gatorade

And with all that hydration (plus race-day nerves), expect long bathroom lines:
On Sunday, more than 1,600 portable toilets will be available for the runners. That works out to about one port-o-potty for every 28 runners, but you know the lines will be longer than that!



Data Sources:
ING New York City Marathon website
Running Trip "NYC Marathon by the numbers"
Running USA Annual Marathon Report (2011)
The Weather Channel
Wolfram|Alpha

How much candy?

24.7 pounds = per capita consumption of candy in the U.S. in 2010.
According to Google, 1 pound = 453.59 grams.
According to my personal candy stash, a 58.7 gram Snickers bar* has 280 calories.

With some fancy math, we can figure out that it takes about 7.73 Snickers bars to make a pound, which adds up to 2,165 calories per pound of candy (give or take a calorie).

Multiply that by 24.7 pounds...
and you get more than 53,400 calories worth of candy consumed per year, per capita, in the U.S.

Divide that by an approximate 105 calories per mile run

...and you would need to run more than 509 miles (19 marathons!) to burn off the average American's annual candy consumption!

*Note: I used what I had available. Different candies might yield somewhat higher or lower results.

Data sources:
U.S. Census Bureau, Current Industrial Reports, Confectionery: 2010
Google Calculator
Runner's World "How Many Calories Are You Really Burning?"
Author's calculations

My running log is better than a diary

Having just written about running while traveling, I started to wonder "how many places have I really run?" And in trying to answer that question, I was drawn down an entirely different path...

Back in June of 2003 I started keeping an Excel spreadsheet of all of my key workouts. (Yes - I know how much of a dork I am!)

My log includes brief notes about where I was running at the time (sometimes very brief... "waterfront" "hills" "lake"... um, where?). I've been a runner for longer, but only really geeked out about it and started the spreadsheet in '03.

So tonight I started looking through my old training logs, and it was a better jog down memory lane than any diary I've ever tried to keep...

I can see my progression over the years, from an 11-minute-mile run/walker to my "slow" long runs being more in the 8-9 range. I can see that I have occasionally had down times - months where my pace slowed or training slacked off - but so far I have always rebounded from those times.

There was also a brief period where I was a triathlete. (But we won't speak of that now as I haven't been on a bike in 3 years...)

Most interestingly, I can see almost 10 years of my history... In the mid-2000s I apparently couldn't get enough of Sedona, AZ. (Really? Did I go there that often?) Before that, I'd fly across the country every 3-4 months to visit my family and while there I'd run in my old neighborhood. But eventually we all smartened up and decided that it was more fun to meet at an interesting destination somewhere in the middle. As a result, I've added runs in New York City and Napa to my list.

I've logged many miles alone. I've also had a few running buddies by my side over the years, some longer than others, but all important in their own way.

I've run in cities, parks, mountains, and on the beach. I've run in 15 states and four countries (besides the US).

On the darker side of the training logs, I can also see a divorce in the making... not because of running, but it's there in the details. Deciding to train for a marathon didn't seem like a big deal at the time, but in hindsight I realize that goal was the only thing keeping me together as my marriage was falling apart. Time pounding the pavement was time with no fighting, lying, or blaming. It put me in control of something when it felt like I had control over nothing...

Then there was the graduate school phase.

Oh, how working full time and going to school full time puts a crimp in miles logged each week! My grad school records are filled with lots of time on machines in the gym so I could study while running. My running (and waistline) suffered for it, but at least I didn't quit!

And then, a few years later, I can see a new phase in the logbook. I met a man who ran with a group called the San Diego Running Meetup (SDR for short). We went on a few dates. He showed up at a race I was running, unannounced. It was hot. I crashed, burned, and sweat like a pig. I was sure he'd look at my abysmal finish time and be convinced that I was lying about being "a runner." He gave me a hug (sweat and all) and took me out for breakfast.

Then he convinced me to join SDR.

Then he convinced me to do track workouts.

Then we did a 10k the day before our wedding.

The rest, as they say, is history.

My how far we have come

When I was born, the marathon was still a men-only event in the Olympics (and no, I'm not that old!) In the era of Title IX it is difficult to remember that less than a generation ago, women were not grated equal access to sports (not to mention certain educational or occupational opportunities). Improvements in gender equity since the 1960s have been rapid, but the effects of gender discrimination linger in subtle ways.

I recently stumbled across this reminder of how much our sport has changed in the past thirty years:

Not until 1984 in Los Angeles would the women's marathon become a sanctioned Olympic event. Joan Benoit Samuelson, the winner, had attended high school in Maine, where women's track teams were not granted varsity status during her freshman and sophomore years. She won the 1975 state championship in the mile -- the longest distance a woman was allowed to run -- but because she insisted on practicing with the boys to improve her times, she was denied the school's most valuable athlete award. "That's when I said to myself, 'I'll show that coach -- I'm going to win an Olympic medal some day,' " Samuelson says. Nine years later she did.
NY Times (1996)

When I read that, I pumped my fist in the air and yelled "Go Joan!" (My cat, who was napping on my desk, was not pleased...)

I highly recommend reading the entire Times article. The piece is now 15 years old, written for the Atlanta Olympics, but is a timeless history of the challenges women have faced just to be able to be runners. If they had not pushed the boundaries of gender, would we be runners today?

One of the most common excuses for excluding women running was that our bodies "couldn't handle it," and that were not as ______ as men (insert "strong," "fast," "smart," "tough," or any number of other adjectives here).

But are women really weaker or slower than men?

Or did they just get a late start?

Today's marathon world record, still held by Paula Radcliffe from the 2003 London Marathon, represents a pace that is equivalent to the fastest man on earth in the early 1960s. And while men's marathon times have remained (from a statistical perspective) roughly stable over the last century, dropping from 2:55 in 1909 to 2:03:59 in 2006, women's times have seen rapid improvement.

Today the differential in men's and women's paces can be measured in seconds per mile, not minutes.

In 1980 only 10 percent of marathon runners were female. In 2009 the proportion reached 41 percent (data from Running USA). The share of women running in shorter races has risen even faster. In the half-marathon distance, women became the majority of runners in 2005.

And, perhaps most interestingly, women who enter ultra-marathons have a substantially higher likelihood of completing the race than male entrants do.

So it is entirely possible that women can be just as fast as men, but got a late start in this game. Granted, there are runners who make a strong argument to the contrary by suggesting that over the last couple of decades the disparity in paces between men and women has remained roughly constant both in the marathon and in other distances.

This is one case where only time will tell.

And I'll keep this in mind next time I'm at the track doing a speed workout.


Chart data source: http://www.marathonguide.com/history/records/ data compiled by author

Born to Run (and to be anything but a couch potato)

I am about halfway through Born to Run. Having published the latest obesity stats in another blog, this passage struck me:

"Every action flick depicts the destruction of civilization as some kind of crash-boom-bang, a nuclear war or hurtling comet or a self-aware-cyborg uprising, but the true cataclysm may already be creeping right up under our eyes: because of rampant obesity, one in three children born in the United States is at risk of diabetes--meaning, we could be the first generation of Americans to outlive our own children. Maybe the ancient Hindus were better crystal-ball-gazers than Hollywood when they predicted the world would end not with a bang, but with a big old yawn. Shiva the Destroyer would snuff us out by doing... nothing. Lazing out. Withdrawing his hot-blooded force from our bodies. Letting us become slugs."
Christoper McDougall, Born to Run

Today, Colorado has the nation’s lowest rate of adult obesity, at 18.6 percent. In California, with its reputation for athletic-minded surfers and beach bums, one quarter of the adult population is obese. That's right - not just overweight. Obese. In California.

U.S. Centers for Disease Control and Prevention
http://www.cdc.gov/vitalsigns/AdultObesity/StateInfo.html

The rapid change over the past two decades is alarming, to say the least. In 1990 ten states had obesity rates below 10 percent. Today none do. In 1990 no states had obesity rates above 15 percent. Today none have rates below 15 percent.

How has this happened so quickly?

According to the Centers for Disease Control and Prevention, "Many communities are built in ways that make it difficult or unsafe to be physically active."

While I agree that wide, sidewalk-less roads play a role in the obesity epidemic, I also think there is a broader social movement at play... Or rather not moving and not playing?

According to Nielsen, Americans are watching more TV than ever - now up to an average of 34 HOURS PER WEEK per person. People are watching television like it's a full-time job.

Somewhere along the way we've lost our collective interest in getting outside to play, and have turned into a nation of couch potatoes.

I'm hoping that by the end of Born to Run, McDougall will present some suggestions for overcoming our national sloth. Michelle Obama's "Let's Move" campaign is a start in the right direction, but I have to wonder if more people will exercise or will just sit and watch her dance in the Dougie video?


Note:
According to the CDC, obesity is “defined as a Body Mass Index (BMI) of 30 or greater. BMI is calculated from a person's weight and height and provides a reasonable indicator of body fatness and weight categories that may lead to health problems. Obesity is a major risk factor for cardiovascular disease, certain types of cancer, and type 2 diabetes.”