Nutritional intake and gastrointestinal problems during competitive endurance events

Area of Science:

• Sports Science
• Exercise Physiology
• Nutritional Science

Background:

• Limited data exists on the nutritional and fluid intake habits of athletes during endurance events.
• Gastrointestinal (GI) symptoms are common in endurance athletes but poorly understood in relation to intake.

Purpose of the Study:

• To quantify and characterize energy, nutrient, and fluid intake during endurance competitions.
• To investigate the relationship between nutrient intake and GI symptoms in athletes.

Main Methods:

• 221 endurance athletes from Ironman, Half-Ironman, Marathon, and Cycle races participated.
• A post-race questionnaire assessed nutrient intake and 12 GI symptoms.
• Professional cyclists were studied during stage races.

Main Results:

• Carbohydrate (CHO) intake rates varied significantly across events, with lower rates in cycling and marathon races compared to Ironman events.
• Serious GI symptoms were most prevalent in Ironman races, correlating with a history of GI issues.
• Higher CHO intake was linked to increased nausea and flatulence, but also to faster finishing times in Ironman races.

Conclusions:

• CHO intake rates during endurance events show considerable individual and event-specific variability.
• High CHO intake is associated with gastrointestinal discomfort (nausea, flatulence) but also with improved performance in Ironman triathlons.