To assess the evolution of biological markers of mesenteric ischemia during ultratrail.

During physical exercise, increased sympathetic nervous system activity redistributes blood flow from splanchnic organs to working muscles. With prolonged duration and / or intensity, the splanchnic blood flow can be reduced by 80% or more. A severely reduced of splanchnic blood flow can frequently cause gastrointestinal ischemia. This ischemia associated with reduced vagal activity probably results in changes in motility and absorption.

High symptoms are reported in 40% of runners with reflux and heartburn in 15-20% of runners. The low symptoms have an incidence of about 70% in the long runs type ultra-trail.

Biological markers such as I-FABP have been shown to be useful in the diagnosis of mesenteric ischemia.

Inclusion Criteria:

• Healthy Voluntary Subject
• Age > 18 years
• Written consent
• Subject affiliated to Social Security
• Medical certificate (mandatory to take part in the ultra-trail)

Exclusion Criteria:

• Refusal to participate
• Subject with legal protection (guardianship, trusteeship)

participants or populations are selected based on predefined criteria