title: Effects of probiotics supplementation on gastrointestinal permeability, inflammation and exercise performance in the heat.
abstract: OBJECTIVE
  This study aimed to investigate the effects of multi-strain probiotics supplementation on gastrointestinal permeability, systemic markers of inflammation and running performance when exercising in the heat.
  
  
  METHODS
  Ten male runners were randomized to 4 weeks of daily supplementation with a probiotics capsule (45 billion CFU of Lactobacillus, Bifidobacterium and Streptococcus strains) or placebo, separated by a washout period (double-blind, cross-over trial). After each treatment, the runners exercised to fatigue at 80% of their ventilatory threshold at 35 °C and 40% humidity. To assess gastrointestinal permeability, runners ingested lactulose and rhamnose before exercise and post-exercise urine was collected to measure sugar concentrations. Venous blood samples were collected before, immediately after and 1 h after exercise, and core temperature was monitored during exercise.
  
  
  RESULTS
  Probiotics supplementation significantly increased run time to fatigue (min:s 37:44 ± 2:42 versus 33:00 ± 2:27; P = 0.03, d = 0.54). Average core temperature during exercise was similar between trials (probiotic 38.1 ± 0.2 °C, placebo 38.1 ± 0.1 °C; P = 0.77, d = 0.13). Serum lipopolysaccharide concentration increased post-exercise (P < 0.001), while there was a moderate to large reduction in pre-exercise (d = 0.70) and post-exercise (d = 1.24) concentration following probiotics supplementation. Plasma concentrations of IL-6, IL-10 and IL-1ra increased after exercise (P < 0.01), but there was no significant difference between trials (P > 0.05). There was a small to moderate reduction (d = 0.35) in urine lactulose:rhamnose and a small reduction (d = 0.25) in symptoms of gastrointestinal discomfort following probiotics supplementation (both P = 0.25).
  
  
  CONCLUSIONS
  Four weeks of supplementation with a multi-strain probiotic increased running time to fatigue in the heat. Further studies are required to elucidate the exact mechanisms for this performance benefit.
authors.affiliation: Sport Performance Optimisation Research Team, School of Human Life Sciences, University of Tasmania, Locked Bag 1320, Launceston, TAS, 7250, Australia, Cecilia.Shing@utas.edu.au.
authors.forename: Cecilia M
authors.initials: CM
authors.lastname: Shing
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Peake
authors.forename: Chin Leong
authors.initials: CL
authors.lastname: Lim
authors.forename: David
authors.initials: D
authors.lastname: Briskey
authors.forename: Neil P
authors.initials: NP
authors.lastname: Walsh
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Fortes
authors.forename: Kiran D K
authors.initials: KD
authors.lastname: Ahuja
authors.forename: Luis
authors.initials: L
authors.lastname: Vitetta
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D016207:Cytokines / Q000097:blood; D004311:Double-Blind Method; D017079:Exercise Tolerance / Q000187:drug effects*; D041981:Gastrointestinal Tract / Q000187:drug effects*; D006358:Hot Temperature; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000517:prevention & control; D007408:Intestinal Absorption / Q000187:drug effects*; D008297:Male; D019936:Probiotics / Q000494:pharmacology* / Q000627:therapeutic use; D012420:Running
chemical_list: D016207:Cytokines