Anyone who has ever participated in an athletic event, or who has an over-protective mother, has heeded the advice, “Stay hydrated.” But, according to a three-year study done by Tanita Corporation, a world leader in precision scales, hydration very well might be vital for performing well in any race.
In 2004, Tanita partnered up with Ironman. In 2008, they began their study, which took place during athlete registration at the 2008, 2009 and 2010 Ford Ironman Louisville events. Tanita obtained hydration readings of 5,740 competitors over the three-year period. Before each race, after receiving their bib number, the athletes were directed to one of six body composition assessment stations. Using six Tanita BF-522W Body Fat/Body Water Analyzers, Tanita trained assessors asked athletes for their bib numbers, ages and heights. Once this information was inputted into the scales, the barefooted athletes then stood on the devices to complete the analyses. Both the athletes’ bib numbers and hydration levels were then recorded.
Following the event, Ironman provided Tanita with the competitors’ information, including bib numbers and completion times. Bib numbers were referenced and matched with race result data and each individual’s pre-race hydration level was assigned to the appropriate athlete. The results for men and women were then separated, with a total of 4,426 male participants and 1,314 female participants being tested over the three-year time span.
Results showed that the average hydration level of men who finished the triathlon was 60 percent, while the average hydration level of women who finished the triathlon was 55.7 percent. Only 153 out of 227 of the male participants with a pre‐competition hydration level of less than 55 percent were able to finish the race, and only 45 out of 68 of the female participants with a pre‐competition hydration level of 50 percent were able to finish the race.
Essentially, based on their findings, Tanita was able to conclude (with 95 percent confidence) that for every 1 percent increase in the men’s hydration level, their mean time decreased by 16 minutes, and for every 1 percent increase in women’s hydration level, their mean time decreased by 12 minutes. In their study, Tanita said that they believe their findings “represent a strong indication that a relationship exists between hydration percentages and finish time” and that “individuals with higher hydration levels, on average, had better finish times.” Tanita also believes that, based on their collected data, they can predict with 95 percent confidence what the finish time of a racer will be based on their pre-competition hydration level.
So, what’s the moral of the study? Hydration might not be just another factor to worry about before your race, alongside questions about racing conditions and fears about potential gear malfunction. As Tanita writes in their study, “It appears that through this paper, there may be at least one thing they can control that will help decipher their day.”