The Effect of Light Therapy and Acute Aerobic Exercise on Serum Brain Derived Neurotrophic Factor in Older Adults

Purpose: Neurotrophins serve a fundamental role in neural survival, development, function and exercise-dependent synaptic plasticity. Although brain derived neurotrophic factor (BDNF) production decreases as we age, there is a vast amount of support for moderate to high level intensity exercise as a mediator for ramping up production. Limited research indicates light therapy (LT) treatment may also increase peripheral BDNF, leaving the effects of this treatment poorly understood. Establishing methods to maximize the release of BDNF is beneficial to augment cognitive effects. Therefore, the purpose is to evaluate the influence of LT and acute bouts of aerobic exercise (AE) on serum BDNF concentrations in adults over the age of 55. Methods: A total of 6 participants (1 male, 5 female, 67 ± 4.10 years 171 ± 8.41 centimeters, 79.4 ± 6.75 kilograms) completed VO2 max testing and the following three exercise sessions separated by 48 hours: (1) 30 minute LT session, (2) 30 minute cycling session and (3) LT exposure during a 30 minute cycling session. Cycling sessions were completed at 65-75% of maximal heart rate as determined by VO2max, while maintaining 60rpms. Venous blood samples were collected pre and immediately post each condition for serum BDNF quantification. Results: Mean serum BDNF concentrations were not statistically significantly increased between the three conditions or between the two time points. Cohen’s D values suggest small effect sizes for AE (d = 0.27, r = 0.13) and LT (d = 0.28, r = 0.14) conditions, with a very small effect size for the COMB (d = 0.06, r = 0.03) condition. Conclusions: Aerobic exercise and light therapy may separately serve as interventions to increase serum BDNF levels. Combining the two treatments requires additional investigation to determine additive effects