Abstract
Brain-derived neurotrophic factor (BDNF) and secreted amyloid precursor protein-alpha (sAPPα) promote neuronal growth but are lower in people with Alzheimer's Disease (AD). BDNF increases after exercise, but the response may vary with exercise intensity and across blood fractions. While sAPPα rises post-exercise in animals, its response to aerobic exercise in humans is unclear. This study examined how BDNF and sAPPα respond to moderate and high-intensity exercise in healthy young adult humans. Participants completed three exercise conditions: moderate (65% Watt maximum, 30 min), clinical-HIIT (4 × 4 min, 90% Watt maximum), and all-out-HIIT (8 × 30 s, 150% Watt maximum). Blood-based biomarkers were extracted from venous blood drawn from venepuncture at baseline, immediately after exercise, and after 30 min rest. BDNF concentration was measured in serum, plasma, platelet-poor plasma, and platelets; sAPPα in serum via ELISAs. Data were primarily analyzed using mixed effects models. BDNF increased in plasma and platelet-poor plasma across conditions but rose in serum only after clinical-HIIT and moderate intensity exercise. BDNF concentration in platelets was unaffected. sAPPα increased after moderate and clinical-HIIT sessions. Measurement of BDNF in serum alone may not fully represent the changes in BDNF post-exercise. Further research is required in adults at risk of AD.