The effect of environmental temperature on exercise-dependent release of brain-derived neurotrophic factor

Brain-derived neurotrophic factor (BDNF) is a biomarker of cognitive function that is released into the blood stream following exercise, and cognitive function is impaired by environmental temperatures that are hot and cold. Purpose: To evaluate the exercise-dependent release of BDNF in different environmental temperatures. Methods: Recreationally trained males each completed three trials consisting of cycling for 1 h at 60% W_max at three different temperatures: 33°C (hot), 7°C (cold), and 20°C (moderate room temperature). Blood was taken from the antecubital vein pre-exercise, immediately post-exercise, and 3 h post-exercise. Respiratory gases were collected periodically throughout exercise and recovery. Results: BDNF was elevated immediately following an exercise bout (1711 ± 766 pg·ml⁻¹) regardless of temperature from pre-exercise (1257 ± 653 pg·ml⁻¹, p = 0.001) and returned to basal levels following 3 h of recovery (1289 ± 650 pg·ml⁻¹, p = 0.786). There was no effect (p > 0.05) of temperature on BDNF following the exercise bout. Plasma glucose was elevated in hot (6.2 ± 0.9 mmol) over cold (5.3 ± 0.6 mmol, p = 0.035) and moderate room temperature (5.2 ± 0.5, p = 0.008). VO₂ was elevated during exercise in hot (3.01 ± 0.45 L·min⁻¹) over cold (2.67 ± 0.35 L·min⁻¹, p = 0.005) and moderate room temperature (2.80 ± 0.38 L·min⁻¹, p = 0.001). There was no relationship between BDNF and plasma glucose (p > 0.05) or VO₂ across any time point or temperature (p > 0.05). Conclusion: With aerobic exercise, BDNF is elevated; however, the release of BDNF is not impacted by different environmental temperatures during exercise.