The effect of N,N-dimethylglycine on athletic performance at altitude in horses and mules

N,N-dimethylglycine (DMG) is widely used to delay fatigue by inhibiting lactate production. DMG effects were examined in a paradigm of moderate exercise intensity that was potentially oxygen-limited. Performance in seven horses and four mules was assessed using blood lactate concentrations and heart rates. The experimental group was administered 2.2 g of DMG twice per day for four days. The exercise tests consisted of two exercise bouts, one starting at an elevation of 2635m and the other at 1960m. Work at the high altitude increased the total number of heart beats and recovery time in both horses and mules. There were no difference for peak heart rate (152+/-11 vs 141+/-2, p=0.32) average heart rate, (99+/-2 vs 97+/-3, p=0.40) and blood lactates (0.62+/-0.05 vs 0.66+/-0.04 mM, p=0.78) between higher altitude and lower altitude tests, respectively. When data were pooled for species and altitude, DMG reduced blood lactates, (0.60+/-0.03 vs 0.74+/-0.06 mM, p=0.03).