Brain Derived Neurotropic Factor Response To Aerobic Exercise In The Cold

Abstract

PURPOSE: To examine changes in brain derived neurotropic factor (BDNF) concentration in both plasma and serum following exercise in the cold. METHODS: Six recreationally active men (26 ± 3 yrs; 180.3 ± 5.8 cm; 85.3 ± 8.4 kg; 48.6 ± 5.7 ml·kg−1·min−1) completed an exercise protocol under two conditions: moderate temperature (MT; 23°C/45%RH) and low temperature (5°C). The protocol consisted of a 60-minute cycling trial at 60% VO2max, a 15-minute rest, and a time-to-exhaustion trial at 90% VO2max (TTE). Blood was collected before (T1) and after (T2) the 60-minute trial, immediately after TTE (T3), and one hour post-TTE. Plasma and serum concentrations of BDNF were measured via ELISA. Changes were analyzed using separate condition by time mixed-model regression for each dependent variable. RESULTS: No significant condition × time interaction (F = 1.626, p = 0.201) or main effect of time (F =0.626, p = 0.603) was observed for changes in serum BDNF concentrations; however, a significant main effect of condition (F = 7.685, p = 0.009) was observed. When collapsed across time, serum BDNF concentration was significantly lower during LT (2718.8 ± 1172.2 pg/mL) compared to MT (7240.5 ± 1134.2 pg/mL; p = 0.009). No significant condition × time interaction (F = 0.117, p =0.950), main effect of time (F =0.511, p = 0.677) nor main effect of condition (F = 0.000, p = 0.988) was observed for changes in plasma BDNF concentrations. CONCLUSIONS: The results of this study suggest that exercise in a cold environment (5°C) blunts serum BDNF concentration. However, plasma concentrations of BDNF were not affected by environmental condition nor exercise. Previous research has found no relationship between serum and plasma BDNF, suggesting that these are independent measures of diverse physiological relevance. Peripheral BDNF is predominantly stored in platelets (~99%), with only a small amount of free BDNF present in plasma. Due to the smaller amount of platelet-associated BDNF in plasma, plasma concentrations of BDNF may reflect the amount of free BDNF. Therefore, exercise in a cold environment may decrease BDNF release from platelets while having no effect on free BDNF. This study was partially funded by the Kent State University Research Council.