I like when quantitative knowledge helps us spot patterns and achieve insights that we might have in any other case missed. Typically, although, the numbers merely assist us articulate a phenomenon we already knew existed. That’s definitely true in terms of speaking in regards to the influence heat temperatures play on runners’ performances on the infamously sizzling Western States 100, which takes place yearly in California in the summertime.
There’s an present physique of analysis confirming hotter temperatures are linked to slower ending instances in endurance operating. Many of those research deal with the marathon distance, equivalent to these from 2019, 2012, and 2012). Ultrarunners are additionally affected by the warmth, in fact, which is why we incorporate warmth acclimation into our race preparation, undertake methods for dealing with the psychological pressure of racing within the warmth, and make the most of cooling methods to mitigate its physiological results.
When Joe Uhan described the Western States 100 as a “killing machine” that chews up and spits out ultrarunners, he recognized the warmth as a major contributor to that carnage.
This month’s version of “Working the Numbers” is right here to inform you an identical factor, however with some charts. We additionally look briefly into how course situations — particularly residual snow within the race’s greater elevations — have an effect on runners’ ending instances.
We’re publishing this text simply forward of the 2023 version of the race, the place temperatures are forecasted to be effectively beneath regular for the area. It’s nonetheless going to be heat although, and that heat will play into the race dynamics. The area noticed traditionally excessive snowfall within the winter of 2022-2023, and never all of that snow has melted, so runners will expertise the results of this, too.
On this article, we uncover some nice nuance by digging into the information, so learn on for insights on how temperature and course situations influence runners by ending hour, age group, and gender.
Beth Pascall main the ladies at Robinson Flat (mile 30) on a sizzling day on the 2021 Western States 100. Picture: iRunFar/Bryon Powell
Methodology
The Western States 100 is one among my favourite races to investigate as a result of it has a powerful tradition of information: The entire knowledge for this text comes from the Western States web site and its outcomes on UltraSignup. For this text, I solely thought-about race outcomes from 1985 onward as a result of, in accordance with the Western States web site, earlier editions of the race had been shorter than its present distance of 100.2 miles. I additionally didn’t need finisher charges from the earliest years of the race to skew the outcomes since, for instance, the primary 4 editions had a mixed 17 runners begin the races with solely 5 finishers.
To check race outcomes throughout years, I took a subset of race outcomes from the most well liked and coolest editions of Western States, based mostly on the warmest temperature reached on race day (the daytime excessive). I coded any 12 months the place the daytime excessive was 85 levels Fahrenheit (29 Celsius) or cooler as a “cool” 12 months, and years the place the daytime excessive was 95F (35C) or hotter as “sizzling” years. This by itself emphasizes how a lot warmth performs a think about performances at Western States, as a result of I in all probability wouldn’t contemplate 85F to be cool in lots of different contexts. Utilizing this coding system, 9 years had been labeled as “cool” years — the latest being 2019 — and 12 had been thought-about “sizzling” — together with the 2022 and 2021 editions.
Jim Walmsley on his approach to resetting his personal course report on the 2019 Western States 100. With a excessive of 83 levels Fahrenheit, 2019 falls below the heading of “cool” for this evaluation. Picture: iRunFar/Bryon Powell
End Charges Aren’t Strongly Linked to Temperature
First, the excellent news for Western States entrants: There’s not a powerful correlation between greater temperatures and decrease end charges. Whereas the information does point out the warmth slows you down, it isn’t essentially a DNF sentence. The precise danger of getting a DNF on a very sizzling day at Western States might depend upon a person runner, their pacing technique, and the way shut they’d be to cutoffs on a cool day.
The chart beneath exhibits every version of the race, from 1985 onward, as an information level. We didn’t embody a development line as a result of a linear development line would have a low R2 worth, or coefficient of dedication. That determine, between 1 and −1, is meant to measure how reliably you may predict, in our case, the end fee based mostly on the temperature. In different phrases, we will’t confidently say there’s a powerful correlation between hotter temperatures and decrease end charges.
Scatter plot exhibiting the correlation between daytime excessive temperature and finisher fee on the Western States 100.
Western States publishes end charges for every version of the race on its web site, however knowledge on which runners didn’t end (DNF) will not be out there on UltraSignup for all years. Subsequently, I didn’t drill down into whether or not elements equivalent to age group or competitors stage impacted a runner’s probability of getting a DNF.
How the Distribution of Ending Occasions Adjustments with Completely different Temperatures
Proportionally talking, probably the most pronounced results of the warmth are seen on the very back and front of the pack. There are comparatively extra runners ending in 19 hours or much less on cool years when the daytime excessive was 85F or cooler. There are 3% extra runners ending in what is known as the Golden Hour of the race on sizzling years, pushing laborious for finishes of 29 hours or longer however inside the occasion’s 30-hour cutoff.
Bar chart exhibiting the distribution of ending instances on sizzling and funky years on the Western States 100.
This normal development of ending instances being slower on sizzling years is true of each women and men. On significantly sizzling years, each the lads’s and girls’s fields have proportionally extra runners ending within the closing hours of the race.
One fascinating development highlighted within the charts beneath is that there are proportionately extra runners within the males’s area ending between 23 and 24 hours. Western States awards a silver buckle to each runner ending in 24 hours or much less, and it seems that incentive has a extra seen influence on males’s ending instances.
Bar chart exhibiting the distribution of male finishers by the hour on sizzling and funky years on the Western States 100.
Bar chart exhibiting the distribution of feminine finishers by the hour on sizzling and funky years on the Western States 100.
With respect to age group, the warmth seems to have a much less pronounced influence on the ending instances of finishers aged 40 and below. When evaluating leads to cool and sizzling years by ending hour, the proportion of those runners ending inside a selected hour by no means various by greater than 1%.
The results of warmth had been a bit extra pronounced amongst runners aged 40 and over. Finishers in these age teams had been comparatively nearer to the 30-hour cutoff within the hottest years. Notable findings for these runners included:
- Meghan Canfield is the one grand grasp (runners aged 50 and over) to complete in below 20 hours on a sizzling 12 months; ending in a time of 19:30:50 on the age of 52 in 2013, when the temperature peaked at 102F on race day.
- On sizzling years, 37% of all finishers aged 50 or over have a ending time of 29 hours or extra, in comparison with 32% of grand masters finishers in cool years.
- The proportion of masters runners (aged 40 to 49) ending within the Golden Hour jumps from 16% to 23% when evaluating outcomes from the races coolest and hottest years.
Course Circumstances Additionally Have an effect on Ending Occasions
Persevering with with our findings you already knew however can now quantify, the Western States course is quicker when there’s no snow on it.
The Western States course begins in Olympic Valley, California, with runners climbing an escarpment after which spending some miles within the excessive nation earlier than descending into the canyons and ultimately the low elevation end line. Runners are ferried throughout the American River by boat, situated at mile 78 on the race course, on years when water ranges are excessive, and cross on foot with the help of a information rope when water ranges are decrease. Western States publishes historic knowledge for years when snowpack was notable and due to this fact water ranges had been probably excessive and boats had been extra probably used on the river crossing.
For years when Western States has famous average snowpack or a snow route in its outcomes archive, the median ending instances are over 20 minutes slower in comparison with years the place snow situations weren’t noteworthy.
Desk exhibiting ending instances on years with snowpack situations and boat-assisted river crossings on the Western States 100.
Adam Peterman makes his manner throughout the Rucky Chucky river crossing at mile 78 of the 2022 Western States 100. Picture: iRunFar/Bryon Powell
Closing Ideas
Trying to the long run, will probably be fascinating to see whether or not the temperature issue will probably be completely different for runners at Western States. On one hand, extra runners are adopting science-based cooling protocols to mitigate the physiological and psychological results of heat temperatures. However, local weather scientists warn we will count on hotter temperatures and excessive climate equivalent to forest fires to proceed affecting us. I’m deeply invested in that future, however can not touch upon it. I’ve a spreadsheet, not a crystal ball.
Name for Feedback
- Did you count on the influence of warmth on ending instances and finisher charges to be roughly pronounced?
- Does your personal expertise of operating in warmth align with these findings?
- Any last-minute recommendation for Western States 100 runners getting ready to deal with the course and doable warmth?
