Learning elite athletes in real-world endurance occasions affords a uncommon glimpse into the bounds of human efficiency. In biking, few challenges check the physique and thoughts just like the Tour Divide — a 4,385-kilometer, self-supported bikepacking race from Banff, Canada to the U.S.–Mexico border. A brand new research from Brigham Younger College adopted one rider by this grueling journey to uncover how the physique withstands and adapts to such excessive calls for. The outcomes are each shocking and provoking — revealing simply how resilient and adaptable the human physique could be when correctly fueled and examined to its limits.
Learning elite athletes in the actual world is fascinating as a result of they permit scientists to review excessive physiology that’s virtually inconceivable to duplicate within the lab. In biking, probably the most excessive ultra-endurance occasions is the Tour Divide bikepacking race. What can we be taught from finding out the responses of one of many opponents?
I’ll gladly confess that I doubt that I’ll ever participate in a bikepacking “race” or a Quickest Recognized Time (even when that point is simply quickest for me). I obtained into bikepacking 4+ years in the past as a result of, after many years of biking competitors, I wish to really get pleasure from and savour each pedal stroke, view, and sensation.
Having mentioned that, I obtained into train physiology 35 years in the past as a result of I obtained fascinated by how the physique responds to excessive stress. Whether or not it’s warmth, chilly, altitude, or train, I like utilizing these stressors as instruments to see how the physique really features and adapts. The analogy I exploit in educating college students is that you could be take your automotive to a mechanic with complaints that it makes a rattling noise. When the mechanic places it on the hoist and idles it, they inform you that they don’t hear it, to which you reply, “Yeah, it solely occurs once I go above 120 kmh.”
There are some issues you possibly can solely discover out by pushing the system to its limits. So there’s an enormous worth in finding out excessive endurance efficiency to raised perceive how the physique features even at relaxation.
Hyldahl et al. 2024
On the planet of bikepacking races, arguably the largest and most prestigious is the Tour Divide, operating from Banff, Canada 4,385 km right down to the US/Mexico border at Antelope Wells, New Mexico. Usually following the backbone of the Continental Divide, the route takes in over 60,000 m of elevation acquire. Climate and altitude are additionally massively variable all through. And naturally, the massive problem with bikepacking races that distinguishes it from professional biking is that the rider is totally self-supported, with checkpoints however no assist stations or exterior help.
In 2024, a Brigham Younger College group was lucky to systematically check a Tour Divide (TD) racer earlier than, throughout, and after the race (Hyldahl et al. 2024).
- The case research targeted on a 47 yr previous male competitor, who in the end took 16 days, 7 h 45 min to finish the race, using a median of 16.8 h/day and 253 km/day with 5.5 h/day sleep.
- Pre-testing occurred at 35 days pre-TD and consisted of: resting metabolic fee, MRI (for physique composition), vascular operate, blood pattern, muscle biopsy, and a graded train check.
- Following the race, the participant was pushed ~15 h again to Utah (with a ten h sleep and three giant meals). After one other evening’s relaxation, the testing was repeated, with a complete time of ~36 h between TD finish and the post-testing.
- Throughout TD, the participant saved a weight loss program log to estimate each day caloric consumption. For vitality expenditure, doubly-labelled water (mainly an oxygen isotope that acts as a tracer) was ingested the day earlier than TD, and urine samples have been collected at days 1, 2, 4, 7, and 9.
Earlier than and After
Take a second to understand the extraordinary exertion we’re speaking about right here. TD racers are usually not allowed to have help not out there to all opponents. No staff cooks, soigneurs, logistics planners, mechanics, or any of the help crew World Tour riders have entry to. So racers have to determine every little thing by themselves. And most significantly, in contrast to stage racing with each day stage begins and finishes, the clock by no means stops.
Given this and the intense exertion, most likely the largest shock was the general theme of lack of main modifications earlier than and after the TD on this racer. This may be seen within the comparatively minimal modifications to physique composition, from total physique mass and whole physique water right down to muscle and fats mass modifications. There was a slight lower in trunk muscle mass and a rise in leg muscle mass, however pretty minor modifications in fats quantities.
Maximal oxygen uptake didn’t change in any respect, staying at 59.6 mL/kg/min, nor did maximal energy output. Resting vitality expenditure elevated from 1882 to 2011 kcal/day. Blood markers have been additionally pretty unchanged together with creatinine (typically used as a marker of muscle harm), although some moved barely past regular ranges.
One attention-grabbing discovering through the graded check was a shift in carbohydrate and fats oxidation. Fats-max (maximal fee of fats oxidation) was decrease total and occurred at a decrease share of VO2max post-TD. This was supported in muscle biopsy evaluation of the speed of oxygen flux. As an alternative, there gave the impression to be a shift in direction of better carbohydrate reliance for metabolism.
Lastly, vascular operate (the response of the blood vessels) was significantly diminished post-TD, which is exceptional in that maximal oxygen uptake was nonetheless maintained.
How May We Study From the Execs?
One final result of this case research is one other instance of the exceptional means of the human physique to not simply survive however to thrive even below excessive stress.
- Regardless of some proof of decrements in physiological capability, it’s attention-grabbing how final efficiency capability remained largely unaltered. Whereas we don’t know the way the physique compensated on this case or normally, the truth that it occurred is what retains physiologists like myself working.
- There was a powerful matching of caloric consumption with vitality expenditure, and likewise upkeep of physique mass and total physique composition. That is exceptional given the difficult logistics of a bikepacking race. It means that the physique is able to adapting so long as it’s sufficiently fueled, highlighting the significance of dietary planning.
The most important takeaway for all of us? Don’t be afraid to push your limits. With correct planning and coaching, your physique can take you a lot additional than chances are you’ll suppose!
Journey quick and much, and have enjoyable!
References
Hyldahl RD, Gifford JR, Davidson LE, et al (2024) Physiological evaluation of a 16 day, 4385 km ultra-endurance mountain bike race: A case research. Experimental Physiology 109:165–174. https://doi.org/10.1113/EP091260
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