The Influence of Age and the Val66Met Polymorphism on Serum BDNF Following Moderate Exercise

Brain-derived neurotrophic factor (BDNF) is a biomarker associated with improved brain health. Acute exercise can elevate circulating BDNF; however, individual differences have been reported for the upregulation of BDNF. This study examined serum BDNF levels following moderate-intensity continuous aerobic exercise (AE), the serum BDNF differences between young and older individuals, and the change in serum BDNF between bdnf (Val66Met) polymorphisms. Eighteen physically active, young (n = 7; age, x̄ = 20.0 ± 1.5 yrs) and older (n = 11; age, x̄ = 48.3 ± 7.1 yrs) subjects volunteered and gave informed consent to participate in the study. Each subject performed a graded exercise test on a treadmill with breath-by-breath analysis to establish VO2 max and a 20-minute steady state (60% VO2 max) exercise session on a later date. BDNF was measured via venous blood samples drawn before, immediately after, and 20 minutes after the exercise session. Samples were prepared and stored at -80°C and BDNF was measured in triplicate using an automated Simple-Plex ELISA. Genotype analysis was conducted by collecting buccal epithelial cells using a mouth rinse of 0.9% saline, and DNA was extracted via cell lysis using proteinase k and DNA spin columns. Allelic discrimination for the bdnf gene (rs6265) was acquired in duplicate with positive and negative controls via 40 cycles of qPCR amplification. SPSS (v.18) was used to run a 2 (condition) x 2 (genotype) and a 2 (condition) x 2 (age) ANOVA with repeated measures for mean differences. The results suggested that an acute session of moderate AE produced a non-significant main effect of exercise on BDNF, p = 0.06 (pre-exercise, x̄ = 24.39 ± 10.9 ng/ml vs. post-exercise, x̄ = 27.02 ± 12.0 ng/ml). For the main effect of age, older adults had significantly higher BDNF levels (31.6 ± 9.4 ng/ml) than younger adults (x̄ = 16.7 ± 8.1 ng/ml). Significant interaction effects showed that older and younger significantly increased BDNF during exercise (p = 0.03). Simple effects tests showed that older adults increased BDNF by 4.9% (1.49 ng/ml) and younger adults by 30.1% (4.42 ng/ml). The main effect of genotype showed no significant differences in the wildtype Val/Val or the combined Val/Met: Met/Met genotype (p = 0.13). Interaction effects did not show any differences (p= 0.36); however, Val/Val showed a marked increase in BDNF compared to combined Val/Met: Met/Met carriers following exercise, 2.8 ng/ml (15.2%) and 0.9 (3.7%), respectively. The current observations suggest that an acute bout of AE produced a modest 10.9% increase in serum BDNF following exercise. In addition, older adults showed higher serum BDNF levels; however, the younger group demonstrated a more significant change with exercise. Finally, the Val/Val carriers demonstrated a higher increase in serum BDNF compared to the Val/Met: Met/Met carriers. The lower statistical power of the genotypic analysis warrants increased investigation. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.