Abstract
The study aimed to determine circulatory endotoxin concentration, cytokine profile,
and gastrointestinal symptoms of ultra-endurance runners (UER, n=17) in response to
a 24-h continuous ultra-marathon competition (total distance range: 122–208 km) conducted
in temperate ambient conditions (0–20°C) in mountainous terrain. Body mass and body
temperature were measured, and venous blood samples were taken before and immediately
after competition. Samples were analysed for gram-negative bacterial endotoxin, C-reactive
protein, cytokine profile, and plasma osmolality. Gastrointestinal symptoms were also
monitored throughout competition. Mean exercise-induced body mass loss was (mean±SD)
1.7±1.8% in UER. Pre- and post-competition plasma osmolality in UER was 286±11 mOsmol·kg−1 and 286±9 mOsmol·kg−1, respectively. Pre- to post-competition increases (p<0.05) were observed for endotoxin
(37%), C-reactive protein (2 832%), IL-6 (3 436%), IL-1β (332%), TNF-α (35%), IL-10
(511%), and IL-8 (239%) concentrations in UER, with no change in the control group
(CON; n=12) observed (p>0.05). Gastrointestinal symptoms were reported by 75% of UER,
with no symptoms reported by CON. IL-10 (r=0.535) and IL-8 (r=0.503) were positively
correlated with gastrointestinal symptoms. A 24-h continuous ultra-marathon competition
in temperate ambient conditions resulted in a circulatory endotoxaemia and pro-inflammatory
cytokinaemia, counteracted by a compensatory anti-inflammatory response.
Key words
inflammatory - cytokinaemia - endotoxaemia - sleep deprivation - energy balance -
physical exertion
