Aerobic glucose metabolism during exercise in warmblood horses

The aim of the research presented here is to quantify glucose metabolism during moderate exercise in warmblood horses employing the hyperglycemic clamp technique. Seven healthy warmblood mares, all in diestrus, with an average age and weight of 11.6 ± 2.4 years and 569 ± 40 kg, were fasted for 12 hours. These horses were subjected to a hyperglycemic clamp in five different intervals of work: At rest 1 (until steady state plasma glucose concentrations were reached with a minimum of 30 minutes), walk (10 minutes, 1.5 m/s), trot (20 minutes, 4.4 m/s), walk (10 minutes, 1.5 m/s), and finally rest 2 (same conditions as first rest). The average amount of glucose metabolized (expressed in M: The amount of glucose taken up per kg bodyweight per minute) was calculated and analyzed by a one-way ANOVA statistical test with post hoc Bonferroni adjustments. M-values were observed of 15.0 ± 2.1 at rest (1), 25.1 ± 6.2 at walk (2), 37.4 ± 9.1 at trot (3), 33.0 ± 13.1 at walk (4), and 18.7 ± 4.6 µmol/kg BW/min at rest (5). The amount of glucose metabolized differed significantly between 1 and 3 (p = 0.000), 1 and 4 (p = 0.002), 3 and 5 (p = 0.001), and 4 and 5 (p = 0.022). In conclusion, glucose metabolism more than doubled in trot compared to rest and shows a lag phase during recovery. These results are compatible with previous work using radio-labeling