To determine the relationship between dietary intake, body composition and incidence of upper respiratory tract infections in triathletes during training and competition for the Ironman

[摘要] ENGLISH ABSTRACT: Background: The Ironman® triathlon is an ultra-endurance event. It has previously beenshown that heavy training schedules and racing ultra-endurance events can lead to immuneimpairment. Evidence supporting the potential role of dietary intake and body composition onimmune impairment or upper respiratory tract infections (URTIs) is currently lacking.Aim: To investigate the relationship between dietary intake, body composition and theincidence of URTI in triathletes residing in Port Elizabeth (PE), during training and competitionfor the Ironman® 2011 triathlon.Method: An observational longitudinal descriptive study with an analytical component wasconducted. The study population included triathletes living in PE, who completed an Ironman®distance event one year prior to, and who were training for the April 2011 Ironman®. Habitualdietary intake was assessed with a quantitative food frequency questionnaire; and racedietary strategies with a three day food record. Body composition was determined withanthropometry and the incidence of URTI was assessed with the WURSS-44. A generalhealth screen (SF-36) was also administered.Results: Habitual dietary intake during the three months pre- and post-Ironman® 2011triathlon was adequate for all nutrients except for carbohydrate intake in female and maleparticipants (pre-Ironman® of 4.0 (1.7) g/kg body weight (BW)/day and 5.4 (1.8) g/kg BW/day;and post-Ironman® 3.0 (1.0) g/kg BW/day and 4.7 (1.5) g/kg BW/day respectively).Carbohydrate-loading strategies were below recommendations with intakes of 6.0 (2.9) and5.1 (2.5) g/kg BW/day for female and male participants respectively. Race day nutritionstrategies were below recommendations for carbohydrate intake. Post-race dietary intake wasbelow recommendations for carbohydrate in the female participants (0.9 (0.5) g/kg BW). Bodymass index was 26.6 (3.4) kg/m2 and 26.1 kg/m2 (1.40) for female and male study participantsrespectively. Body fat percentage was at the upper end for endurance athletes (29.3 (9.4) %and 13.7 (5.1) % for females and males respectively). In this study 25 % of the triathletes(N=20) developed an episode of URTI during the 3 months post-Ironman®. Dietary intakeparameters measured three months pre-Ironman® that had a significant influence on URTIwere: potassium (p=0.04) and thiamine (p=0.02) and dietary intake parameters measured 3months post-Ironman® that had a significant influence on URTI were: total protein (p=0.04);isoleucine (p=0.03); leucine (p=0.03); phenylalanine (p=0.03); valine (p=0.02); thiamine(p=0.01); and Beta-tocopherol (p=0.03). Dietary intake parameters measured during the race that had a significant influence on URTI were: selenium (p=0.04); folate (p=0.04) and proline(p=0.02). Body composition did not have a significant influence on URTI.Conclusion: Habitual dietary intake three months pre- and post-Ironman® as well as pre- andpost Ironman race strategies were low for carbohydrate. Body composition indicated thatathletes were at the upper end associated with endurance sport. There was a relationshipfound between an episode of URTI and dietary intake.

[发布机构] Stellenbosch University