Acute high-intensity interval running increases markers of gastrointestinal damage and permeability but not gastrointestinal symptoms
Jamie N. Pugh Applied Physiology, Nutrition, and Metabolism 2017
Purpose To investigate the effects of high-intensity interval (HIIT) running on markers of gastrointestinal (GI) damage and permeability alongside subjective symptoms of GI discomfort.
Methods Eleven male runners completed an acute bout of HIIT (eighteen 400 m runs at 120% VO<sub>2max</sub> ) where markers of GI permeability, intestinal damage and GI discomfort symptoms were assessed and compared with resting conditions.
Results Compared to rest, HIIT significantly increased serum lactulose:rhamnose ratio (0.051 ± 0.016 vs. 0.031 ± 0.021, p = 0.0047; 95% CI = 0.006 - 0.036) and sucrose concentrations (0.388 ± 0.217 vs 0.137 ± 0.148 mg.l-1; p < 0.001; 95% CI = 0.152 - 0.350). In contrast, urinary lactulose:rhamnose (0.032 ± 0.005 vs 0.030 ± 0.005; p = 0.3; 95% CI = -0.012 - 0.009) or sucrose concentrations (0.169 ± 0.168% vs 0.123 ± 0.120%; p = 0.54; 95% CI = -0.199 - 0.108) did not differ between HIIT and resting conditions. Plasma I-FABP was significantly increased (p < 0.001) during and in the recovery period from HIIT whereas no changes were observed during rest. Mild-symptoms of GI discomfort, were reported immediately- and 24 h post-HIIT, although these symptoms did not correlate to GI permeability or I-FABP.
Conclusion Acute HIIT increased GI permeability and intestinal I-FABP release, although these do not correlate with symptoms of GI discomfort. Furthermore, by using serum sampling, we provide data showing that it is possible to detect changes in intestinal permeability that is not observed using urinary sampling over a shorter time-period.