Are splanchnic hemodynamics related to the development of gastrointestinal symptoms in Ironman triathletes? A prospective cohort study.

OBJECTIVE

To determine if prerace to postrace changes in superior mesenteric artery (SMA) and coeliac artery hemodynamics were related to the development of gastrointestinal (GI) symptoms during a triathlon.

DESIGN

Prospective cohort study.

SETTING

Field study at an international Ironman Triathlon.

PARTICIPANTS

Fifty-nine Ironman triathletes of whom 59% (n = 35) reported GI symptoms (GI group) during the race and 41% (n = 24) remained asymptomatic (CON group).

ASSESSMENT OF RISK FACTORS

Prerace questionnaire (personal details, racing and training history, personal general medical history, and medication) and splanchnic hemodynamics.

MAIN OUTCOME MEASURES

Prerace and postrace measurements of splanchnic hemodynamics [artery diameter, systolic velocity, diastolic velocity, and resistive index (RI) of the SMA and coeliac artery] using duplex Doppler ultrasound.

RESULTS

There was a significant decrease in the diameter of the SMA after the race (P = 0.003) and a significant decrease in the RI of the SMA and coeliac artery (P < 0.001) in both the GI and CON groups, but there were no significant differences between the groups. The only significant risk factor for the development of GI symptoms was younger age (P = 0.041). Other risk factors, including high-intensity exercise, poorly trained athlete, and medication use, were not associated with the development of GI symptoms.

CONCLUSIONS

The hypothesis that altered blood flow is related to the development of GI symptoms in endurance athletes is not supported by the results of this study. Other mechanisms for GI symptoms associated with endurance exercise should be investigated.