Sweat and electrolytes in archers: Esen 2025 study

The group that had followed six Turkish archers at a European Cup came back a year later with eight athletes from the same national team, four men and four women, across the four days of a World Cup stage in May 2023, with 23.7 °C on the field. Four were Olympians or World and European medallists. The men averaged 21 years, 65.1 kg and 179.3 cm, the women 19 years, 60.1 kg and 162.3 cm.

The men ate more than the women: 2,889 kcal a day on average against 2,353 (p = 0.007) and 5.3 g of carbohydrate per kilogram of body mass against 3.9 (p = 0.046). Intake followed the daily load, which fell from 178 arrows, 119 minutes and 5,119 metres walked on day one to 97 arrows, 53 minutes and 2,260 metres on day four: energy intake went from 3,041 to 2,094 kcal and carbohydrate from 5.7 to 3.2 g per kilogram. During competition itself carbohydrate ranged from 43 g an hour on the two full days to 14 on the lightest, with 0.66 litres of fluid an hour and no difference between the sexes. Mean intake and estimated expenditure moved together (r = 0.77 between energy intake and expenditure, p = 0.026).

On sweat the main finding is that the men sweated more than the women (p = 0.002), with a mean body mass loss of 0.58% across the competition day. Sweat sodium concentration was similar in both sexes, around 45 mmol/l, which works out at about 416 mg an hour; sweat potassium was 3 mmol/l in the men and 4.6 in the women. Urine specific gravity did not differ between days or between sexes and stayed below the 1.020 threshold, with the usual rise on waking compared with before (p = 0.029) and after competition (p = 0.028).

The protocol repeats the 2024 study and adds fluid balance. Arrows, duration and metres walked were observed and counted by hand, because electronic devices are not allowed in competition, and energy expenditure is again an estimate, from resting metabolic rate calculated with an equation validated in athletes plus the metabolic equivalents of the activities. Food was recorded with diaries backed by photographs and analysed with Nutritics; meals were buffet style and designed by a nutritionist, and at the venue there was a fuelling station with sports drinks (about 36 g of carbohydrate in half a litre), gels (about 25 g), granola, protein bars, caffeine (about 200 mg per shot) and nitrate from beetroot juice. Every container and food item was weighed before and after consumption.

Body mass was measured before and after the session on a digital scale in minimal clothing, with the bladder voided both times; urine passed during the day was collected and weighed, and total sweat loss was derived from the mass difference corrected for what went in and out. Sweat was collected with absorbent patches applied to the scapula and the thigh for the whole session, on skin cleaned with deionised water, extracted with a syringe and analysed on site within about 15 minutes of the end, using ion-selective electrodes for sodium and potassium; total losses come from concentration multiplied by sweat volume. Hydration was assessed with urine specific gravity read on waking, before and after competition and before bed. All four women were in the luteal phase, established by each archer declaring the twentieth day from the start of menstruation; hormonal contraceptive use was not recorded.

Eight archers, four of each sex, at a single event: the authors answer that this is the complete national team of a leading country, which is a good argument about level and no argument at all about the precision of the estimates. With four women and four men, a comparison between sexes on measures as individually variable as sweat remains indicative. Energy expenditure is calculated rather than measured, and intake comes from diaries, with the known limits of that method. The daily load depended on results in the head-to-head matches, so it was not under the researchers' control.

Some of the numbers do not line up. The sweat table carries a footnote saying potassium was higher in the women, and the values agree with it (3 mmol/l in the men against 4.6), while the paper's own summary and discussion say the opposite, that it was higher in the men; this record reports the table. The sweat rate in litres per hour, which is the headline sex difference, appears only in a figure and not in the table, although the table caption announces it. Several probabilities are written in a way that contradicts the conclusion attached to them: a p of 0.29 and one of 0.16 are treated as significant differences, and the normality of the data is declared with a Shapiro and Wilk test at p less than or equal to 0.05, which inverts the rule. As in 2024, no score was collected: the study says nothing about what happens on the target. All four women were in the same phase of the cycle, and the authors concede they cannot rule out different intakes in other phases, although they consider fluid balance stable.

For an archer, the value of this study lies in the reference numbers it gives for a real competition day, with the caveat that the day in question was 24 °C rather than hot. Mean body mass loss was 0.58%, well below the 1 to 2% that in other sports is linked to a drop in performance, and urine specific gravity stayed in the euhydrated range. These archers drank about two thirds of a litre an hour and, on the long days, took in around 40 g of carbohydrate an hour, figures that sit inside the general recommendations for one to three hours of effort.

On the comparison between men and women the message is simpler than the title promises: the amounts of food differ, following body size, while hydration status measured from urine was the same. The authors suggest that men, sweating more, need more fluid, and that is their recommendation rather than a measured result, because nobody changed anyone's intake to see what would happen. What remains is that at this event no archer, of either sex, arrived at the shooting line dehydrated.