Estimated fluid and sodium balance and drink preferences in elite male junior players during an ice hockey game


Journal Title (Medline/Pubmed accepted abbreviation): Appl. Physiol. Nutr. Metab.
Year: 2011
Volume: 36
Page numbers: 145-152
doi (if applicable): 10.1139/H10-098

Summary of Background and Research Design

Background:Athletes undergo significant losses of water during intense training and competitions. When water loss reaches 2.0%, performance often suffers. However, compared to football, soccer, and basketball, ice hockey is played in a cold environment and players experience many opportunities to rehydrate during a game. It is unknown if dehydration is an issue in the average ice hockey player.

Urine specific gravity (USG) is a measure of the concentration of solutes in the urine. A lower number (closer to 1.0) indicates good hydration.


Hypotheses: Due to the intense, competitive nature of games, 1) hydration status would be better before a game than before practice, 2) total sweat losses would be greater during a game than during practice and there would be higher incidences of dehydration after a game, 3) sodium losses would be greater after a game than after practice. Additionally, 4) education and individualized advice on hydration would improve hydration status during a subsequent ice hockey game.

Subjects:24 elite, Canadian ice hockey players, age 18.3 ± 0.3 y.

Research design:observational

Experimental protocol:The hydration status of 6-8 players was assessed in 4 games over 2 seasons. Six players were monitored at 2 games to test the effect on intervention. About 1 hr before the game, subjects voided their bladders from which they provided a sample which was measured for USG. Less than 1.020 was considered hydrated. All urine passed from that time until the end of the game was collected. All fluid intake during the game (water, Gatorade, or Gatorade + GatorLYTES) was monitored. Sodium loss from forehead sweat was estimated previously to assess sodium losses (Palmer et al., 2010). Players were weighed before and after the game to determine total body mass loss. Data from forwards, defensemen, and goalies were assessed both separately and together.

Summary of research findings:
  • Players were all in a hydrated state at the start of the hockey match.
  • Players lost an average of 3.2 ± 0.2 L of sweat during each game. With the combination of water consumption during the 3 periods (average of 0.3 ± 0.1 L) and water and Gatorade during the 2 intermissions (average 0.2 ± 0.01 L of water and 0.2 ± 0.03 L of Gatorade), the players replaced 66% ± 5% of sweat losses. The 2 goalies lost less sweat and replenished more of their fluid loss during the game.
  • One-third of the players lost between 1.8 and 4.3% of their body mass during the game. This is enough to potentially effect performance.
  • Players lost an average of 3.1 ± 0.3 g of sodium and ingested 0.8 ± 0.2 g of sodium during the game (only about 15% replacement). Sodium replnishment was greatly increased when GatorLYTES was consumed. However, all players were sodium deficient after the game regardless of their beverage choice.
  • The 2 games flanking the individual advice on fluid and electrolyte replacement were too different in regard to playing time, sweat loss, and sodium loss to draw practical conclusions. However, more GatorLYTES was consumed in game 2 by 4 of the 6 players than in game 1, perhaps in attempt to improve hydration status.

Interpretation of findings/Key practice applications:

Despite the cold temperatures, ice hockey is physically demanding and heavy pads are required, leading to large sweat losses during play. It is important for players to consume fluids to replenish their water losses as well as high electrolyte beverages to replenish sodium losses.

Limitations:

It would be interesting to see if performance was affected in those who more effectively replenished their fluid losses.
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