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Ask any runner at the top of their game what the most important things are for running in the mountains for an extended period, and you will likely receive the answer of water, fuel, or in most cases, both. The need for proper hydration and fueling becomes more critical as distances ramp up and as temperatures begin to warm. Some people swear by either solid foods or liquid calories, but that is a different topic for another day. At the root of this dilemma is the penultimate question of how to carry the damned water, to begin with. 

Again, ask any runner at the top of their game, whether that is professionally or recreationally, what the best way to carry water is, and you will likely receive the dreaded answer of, “it depends.” A term that is fraught with so much uncertainty that it makes the most undeceive person cringe. In a sport where water is life, a non-direct answer for such a crucial question leaves all involved shaking their heads—pondering if anything even matters at all. 

However, fear not, for this article will attempt to peel back the layers of the water “onion,” trying to use science to get the core of the most efficient way to carry liquid while on the run. Recent studies have focused on three different carrying systems. 

 If you haven’t guessed already by the title, those systems are handheld water bottles, waist belts, and hydration packs.  In particular, a study conducted by Frontiers in Physiology, a multinational team of doctors, focused on the impact of such hydration systems on the running economy (RE) of twelve different male runners on a treadmill.  

These runners ranged in age from 18-30 and were selected through advertisements at local universities and run clubs, with the caveat that their 10k time had to be less than an hour. Such requirements ensured that the pool was generally in good shape.  Additionally, each runner was instructed not to consume alcohol or caffeine before running and was encouraged to refrain from intense exercise during the testing period.  Furthermore, testing was strictly limited to treadmills, and the participants were encouraged to wear the same clothing and shoes throughout the entire study.  The only variable subject to change was the hydration system that each participant was required to carry on specific days.  

The study design included a total of five test days, at least 24 hours apart.  The first test included an incremental exercise test, followed by four tests in a simple randomized order, comparing the different carriage systems and control conditions as detailed below.  If you want the exact scientific and physiologic parameters tested, you can find them in the referenced article. For the sake of your time and my own, I have skipped explaining this section and instead cut to the proverbial last page of the “book.” In other words, the results, aka what everyone reading likely cares about.

In general, the study admitted that previous studies generally held that backpack weight should be kept to a minimum and that any weight should be carried closer to the center of gravity for a more efficient running economy.  The study also found that the RE, cardiovascular effort, lactate, and RPE thresholds and measurements “deteriorated over time across all systems…no one single system was more economic.” In sum, the study concluded that “the choice of carriage system has no significant influence on economy, HR, lactate, or RPE.”

The study did find that certain factors were slightly affected by the type of carriage system used, but not to the extent that resulted in substantial change during the study. For handhelds, it was found that such carrying devices altered the runners’ natural gait.  However, the body was able to adjust subconsciously so that RE and heart rate were not affected.  For the backpack, the study found that as weight increased, running time and speed decreased, while the heart rate slightly increased.  For the weight belt, no significant impact was seen, and the results were similar to those of a handheld carriage system. 

So what the hell does this mean? Well, I guess to bring things full circle, it depends. It depends on the runner’s preference, what the runner has trained with, and what might best suit the race/terrain that they are expecting to encounter on their next outing.  So with that in mind, knowing that in the end it doesn’t matter how you get that high-quality h2o from point a to b, what is your preferred way to carry water, and why?