The Effects of Exercise on Cognitive Function, Balance, and Salivary Brain Derived Neurotrophic Factor in Healthy Individuals – A Pilot Study

Objective: The purpose of this pilot study was to explore the effect of a four week exercise program on physiological, cognitive, and balance variables and salivary brain-derived neurotrophic factor (BDNF) concentrations in a sample of healthy, physically active individuals. Subjects: Ten healthy participants (3 females, 7 males; age M=22.9 years; SD=2.28; height M=171.20 cm; SD=6.91; and body mass M=74.94 kg; SD=12.29) were included. Methods: Subjects completed two assessments (pre- and post-exercise program) and 12 supervised exercise sessions over the course of four weeks (3 sessions/week). The pre- and post-exercise program assessments included the collection of a saliva sample to measure salivary BDNF concentrations followed by anthropometric measures, resting heart rate, and blood pressure; the administration of the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery to measure neurocognitive function; and finally the completion of the Balance Error Scoring System (BESS) protocol to measure balance variables including the number of errors, displacement in the centre of pressure (COP), average velocity of COP, and area of COP. The exercise sessions consisted of a warm-up, followed by 20-35 minutes of aerobic activity, and concluding with three trials of static balance exercises. The intensity and difficulty of the aerobic and balance exercises were progressed using pre-determined parameters and progressions over the course of the four weeks. The data were analysed using descriptive statistics and Paired Sample t-Tests. The rejection criteria were set at an alpha level p Results: Statistically significant changes in reaction time (t(9)=-2.472, p=.035); BDNF concentrations (t(9)=-1.809, p=.05); average velocity of COP (t(9)=4.69, p=.001) and area of COP (t(9)=4.47, p=.002) in double stance on a foam surface; average velocity of COP (t(9)=3.09, p=.01) and area of COP (t(9)=2.28, p=.04) in single leg stance on a firm surface; average velocity of COP (t(9)=2.65, p=.03) and area of COP (t(9)=3.00, p=.015) in single leg stance on a foam surface; and average velocity of COP (t(9)=2.36, p=.04) and area of COP (t(9)=2.49, p=.04) in tandem stance on a firm surface during the BESS protocol were found. No changes in heart rate, blood pressure, memory, or visual motor speed were observed. No significant changes were seen for the BESS protocol during double stance on a firm surface or tandem stance on foam. Conclusions: The findings of the current pilot study revealed that a supervised four week aerobic and balance exercise program administered to a sample of healthy, physically active individuals resulted in improvements in salivary BDNF concentrations, static balance, average velocity, and area of COP measures. This supervised program requires further investigation into the implementation in a concussed or neurologically impaired population to see if similar benefits are evident in cognitive and balance variables, or BDNF concentration levels.