Author(s): KURMAZOVIC, N., NOMIKOS, T., ARNAOUTIS, G., DJORDJEVIC, B., TODOROVIC, V., KARATZAFERI, C., SAKKAS, G., Institution: FACULTY OF PHARMACY, UNIVERSITY OF BELGRADE, Country: SERBIA, Abstract-ID: 835

INTRODUCTION:
Breath-hold diving (BHD) is an underwater sport that emphasizes oxygen conservation and favors low body mass, which may increase the risk of inadequate energy intake. Low energy availability (LEA; energy availability [EA] <30 kcal/kg fat-free mass [FFM]/day) occurs in both sexes, but data in BHD athletes is lacking. Therefore, the present study aimed to assess LEA in this population.
METHODS:
Fourteen Greek BHD athletes underwent body composition assessment using dual-energy X-ray absorptiometry. Resting metabolic rate (RMR) was measured via indirect calorimetry, and predicted RMR was calculated using the Mifflin–St Jeor equation. Energy intake (EI) was estimated from a 24-hour dietary recall collected on a rest day and analyzed with SOMA Nutri Software. EA was calculated using DXA-derived fat-free mass (FFM); exercise energy expenditure was set to zero due to the rest-day assessment. EI was compared with the minimum energy intake required to avoid LEA (MEI), defined as EA = 40 kcal/kg FFM/day based on threshold shown to support optimal physiological function in exercising men (1). Paired-samples t-tests was used to compare measured vs predicted RMR and EI vs MEI, with Hedges’ g reported as effect size.
RESULTS:
The sample included 14 male divers (age: 40.9 ± 8.0 years; BMI: 25.8 ± 2.1 kg/m²), assessed immediately following the competitive season. Mean EA was 26.3 ± 8.1 kcal/kg FFM/day, and 64.3% met criteria for LEA. Measured RMR (1755.4 ± 280.0 kcal/day) was lower than predicted RMR (1871.2 ± 150.9 kcal/day; p = .055, Hedges’ g = −.53), corresponding to an average underestimation of 6.2% by the prediction equation. EI was significantly lower than MEI (p < .001, Hedges’ g = −1.58), with an average deficit in energy intake of 34.5%. Only one participant (7.1%) met the EA threshold considered sufficient to support optimal physiological function.
CONCLUSION:
High prevalence of LEA was observed in this sample, with EI substantially below thresholds considered necessary to prevent LEA. Measured RMR was moderately lower than predicted, approaching statistical significance. Given the potential health consequences of LEA—including endocrine disruption, reduced bone mineral density, impaired immune function, gastrointestinal disturbances and elevated injury risk—routine screening of BHD athletes for LEA and related health risks is warranted. Additionally, female BHD athletes may be particularly vulnerable and should be included in future studies.

(1) Melin AK, Heikura IA, Tenforde A, Mountjoy M. Energy Availability in Athletics: Health, Performance, and Physique. International Journal of Sport Nutrition and Exercise Metabolism. 2019 Mar 1;29(2):152-164. doi:10.1123/ijsnem.2018-0201.