Preventing cognitive decline through resistance training

The foundations for later-life cognitive health are often laid decades prior to the first symptoms of cognitive decline, therefore preventative strategies should be implemented early in life. Structured resistance training shows promise at reducing dementia risk and has been associated with enhanced cognitive function and biomarker profiles. More specifically, intense acute resistance exercise and chronic resistance training may increase levels of growth factors, such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-1) and vascular endothelial growth factor (VEGF), which influence the proliferation and maintenance of neural and vascular tissue. Furthermore, biomarkers associated with suboptimal cognitive health (e.g., homocysteine) are decreased following longer-term resistance training. Although promising, the current literature is inconsistent, with varying resistance exercise regimens implemented, contributing to conflicting reported effects on cognition and biomarkers. The aim of the current thesis was to evaluate the impact of different strength training protocols on cognitive health. Four studies were conducted to examine acute response in growth factors following resistance exercise in young and older adults, and the chronic response in neurotrophic growth factors and cognitive function following resistance training in older adults. Chapters Four and Five explored the acute response in neurotrophic growth factors to intense resistance exercise in young or late middle-aged adults. Sixteen young adults were recruited (Chapter Four) to perform to-fatigue (i.e., maximal), high-volume acute resistance exercise bouts: i) traditional hypertrophy-based resistance exercise (i.e., three sets, 10 repetitions at 100% of 10 repetition maximum [RM]), or ii) traditional strength-based resistance exercise (i.e., five sets, five repetitions at 100% of 5RM). Levels of serum BDNF and blood lactate concentration (i.e., physiological marker of session intensity) were measured prior to and following exercise. Serum BDNF was increased (p<0.01; d=0.52) immediately post-hypertrophy resistance exercise when compared to strength resistance exercise. Change in serum BDNF levels were positively correlated (r=0.70; p