Regimented Sodium Replacement vs Ad Lib Consumption of High Sodium Fluids in NFL Players

1. Regimented Sodium Replacement vsAd Lib Consumption of High Sodium Fluidsin NFL Players Arthur Bartolozzi, MD Pennsylvania Hospital, Philadelphia PA Sandra Fowkes Godek, PhD West Chester University C Peduzzi, ATC, S Condon, ATC, R Burkholder, ATC Philadelphia Eagles The HEAT Institute of West Chester University

2. Background • We previously reported that hypovolemic hyponatremia occurs in un-supplemented college and professional football (NFL) players Fowkes Godek S, Bartolozzi AR. Changes in blood electrolytes and plasma volume in NFL football players during pre-season training. Athl Train Sports Health Care. 2009;1(6):259-266 • We subsequently supplemented NFL players with Rehydralyte and pickle juice and successfully maintained fluid balance

3. Background • Previous field research indicates that sodium replacement helps maintain sodium balance, plasma volume and body weight in football players during pre-season. • It is unclear whether ad libitum consumption of high sodium fluids maintains sodium and fluid balance as well as athlete specific sodium replacement using high sodium fluids and sodium capsules.

4. Methods • The supplementation protocol took place during the first 10 days of preseason training camp • We measured • blood electrolytes • urine osmolality • changes in plasma volume (% ∆PV) • body mass (% ∆mass)

5. Methods We hypothesized that Fluids would not maintain blood sodium or increase PV compared to Capsules plus fluid replacement.

6. Methods • Change in plasma volumes was calculated from Hct and Hb • Electrolytes were measure by ion-selective electrode • Osmolality was measured by freezing point depression

7. Design and Setting • Observational cohort study • Study conducted during consecutive preseason training camps of one NFL team. • Year1 = capsules • Year2 = fluids

8. Subjects • Eleven NFL players volunteered • 6 players participated in both years and • the other 5 were physically matched • Ht = 187 ± 5cm, • Mass = 113.4 ± 17kg • BSA = 2.38 ± 0.17m2

9. Interventions • Both years the players had 15 practices the first 9 days of camp • Year 1: Capsules - players consumed sodium containing fluids and salt capsules at meals in amounts equal to 50% of daily sweat sodium losses • Year 2: Fluids - players were encouraged to consume sodium containing fluid (458 mg to 1.1 g∙l-1) ad libitum but were not instructed on specifically what to drink

10. Methods • Blood samples for baseline measures were obtained when players reported to camp and prior to the morning practice on Days 3, 5 and 10

11. Methods • Baseline mass was recorded after urine samples ensured euhydration • Capsules osmolality 637 ± 304 mOsm∙kg-1 • Fluids osmolality 725 ± 301 mOsm∙kg-1 • Capsules USG 1.018 ± .008 • Fluids USG 1.018 ± .009

12. Data Analysis • Dependent Variables: • %∆PV • %∆mass • blood sodium • potassium and chloride • Two-way ANOVA with repeated measures and correlated t-tests

13. Results • Mean WBGT during practices for days 1- 9 were not different • Capsules25 ± 3.5ºC • Fluids 25.5 ± 3.1ºC

14. Results - Soduim Sodium was lower on Days 3 and 5 in Fluids versus Capsules 137.8 ± 1.4 vs 140.6 ± 1.5mmol∙l-1 P = 0.004 Capsules group sodium remained unchanged Fluids group returned to baseline at day 10

15. Results - Chloride • Fluids group was lower from baseline on days 3 and 5 and returned to baseline at day 10 p = 0.05 • Capsules group statistically unchanged

16. Results - Potassium Both groups decrease from baseline at day 3 p < 0.01 Capsules group increased above baseline by day 5 p < 0.01 Both groups increased to above baseline by day 10 4.9

17. Results - Plasma Volume • Capsules group PV increased • 11% by day 3, • 12.4% by day 5 • remained at 9.3% elevated by day 10 over baseline • Fluids group PV • Decreased -0.6% on day 3 • Significantly lower than capsules group on day 3 12.4% 11% 9.3%

18. Results – Body Mass • No differences were found for % ∆ mass.

19. Conclusions • Sodium and chloride remained constant during the first 10 days of preseason in NFL players who replaced 50% of their daily sweat sodiumlosses using a regimented dosing with sodium capsules and fluid replacement • In players using ad libidum fluid replacement, sodium and chloride dropped below baseline at days 3 and 5

20. Conclusions % ∆PV was higher on day 3 in the Capsules group and remained elevated while PV did not increase until day 5 in the Fluids group Elevated blood potassium levels occurred in both groups

21. Discussion Our results support the use of individualized dry sodium replacement along with sodium containing fluids during training camp as superior to ad libidum intake of high sodium fluids as a fluid replacement strategy

22. Discussion Plasma volume increase is supported by pill augmentation of sodium replacement and the delay in plasma volume increase using ad libidum replacement may be clinically relevant and may affect performance

23. What specific replacement do each of these athletes need? • Sweat rates are different • Sweat sodium is different • What is the effect on performance

24. Pennsylvania Hospital The Nation’s First Thank You