Do changes in gastro-intestinal blood flow explain high-altitude anorexia?

Eur J Clin Invest 2010; 40 (8): 735–741 Background Gastrointestinal symptoms are common on acute exposure to high‐altitude (HA). Underlying mechanisms are not understood, but vascular shunting away from the gut could be responsible. Therefore, blood flow in the superior mesenteric artery (SMA) and hepatic portal vein (HPV) was examined at sea level (SL) and after ascent to 4392 m (HA). Materials and methods Twelve subjects [eight male, mean age 40 (22–72) years] were studied following an overnight fast and a standard meal. Cross‐sectional vessel area and blood velocity were measured by ultrasound, systolic and diastolic flow calculated for the SMA (HR × vessel area × velocity, cm3 min−1) and mean flow for the HPV. Results All subjects experienced reduced appetite at HA. Blood flow in the SMA and HPV increased following food at SL (mean SMA systolic flow 1024 vs. 3316 cm3 min−1, P