title: Metabolic and cardiorespiratory response in swimmers during head-out immersion: a prospective study.
abstract: BACKGROUND
  Sport represents a stress for the body. Many metabolic and cardiorespiratory changes are known during physical activity.However, litte is known in swimmers particularly during head-out immersion.
  
  
  OBJECTIVE
  To determine the metabolic and cardiorespiratory response in swimmers during head-out immersion.
  
  
  METHODS
  The energetic, cardiovascular function and ventilatory requirements of a 10 min steady state arm exercise performed by 13 healthy subjects in air and during immersion up to the hip in 26°C water were compared.
  
  
  RESULTS
  The same ergometric work load was achieved with an average maximum oxygen uptake of 3.9 ± 2.63 l/min in air versus 3.55 ± 2.48 l/min in water (p=0.953). During exercise, the average values of minute ventilation, ventilation equivalent for oxygen, ventilation equivalent for CO2, peak expiratory flow, respiratory exchange ratio and heart rate were not different in water and in air. However, first ventilatory threshold was significantly higher in water than in air. The mean value of the first ventilatory threshold was 0.89 ± 0.23 l/min in air, and 1.08 ± 0.23 l/min in water immersion; (p=0.016).
  
  
  CONCLUSIONS
  These results suggest that training swimmers favoring immersion (weight belts) may improve their aerobic capacity.
authors.affiliation: El Manar University, Faculty of Medicine, Tunis, Tunisie.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Mesfar
authors.forename: Ines
authors.initials: I
authors.lastname: Zendah
authors.forename: Houda
authors.initials: H
authors.lastname: Gharsalli
authors.forename: Chokri
authors.initials: C
authors.lastname: Ben Hassen
authors.forename: Habib
authors.initials: H
authors.lastname: Ghedira
mesh_terms: D000293:Adolescent; D000328:Adult; D056352:Athletes; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System / Q000378:metabolism; D005080:Exercise Test; D005260:Female; D006257:Head; D006801:Humans; D007101:Immersion / Q000503:physiopathology; D008297:Male; D008660:Metabolism / Q000502:physiology*; D011446:Prospective Studies; D013550:Swimming / Q000502:physiology*; D055815:Young Adult