A single bout of exercise can rapidly improve cognitive functions including memory, attention, and executive functions, which help us navigate through everyday life. However, we do not fully understand the mechanism behind this process. A promising candidate mechanism is lactate, which was previously considered merely a waste product of our muscles during exercise. It is now recognized as an important molecule that is used by the brain as an energy source. Studies have shown that increases in lactate during exercise are positively related to improved cognitive function after completion of exercise. Another potential mechanism involves the increase in neurotrophins such as brain-derived neurotrophic factor (BDNF) following exercise. The increase in lactate and BDNF during exercise may be connected to cause these cognitive improvements.

However, because lactate increases with higher exercise intensities, we currently do not know how lactate specifically impacts brain health. To address this, muscle and blood lactate concentrations can be experimentally manipulated during exercise using sodium bicarbonate (NaHCO3) supplementation and will allow us to explore how lactate specifically affects brain function.

The purpose of this project is to investigate the effect of exercise-induced lactate on BDNF and cognition following oral NaHCO3 supplementation in young adults. We hypothesize that BDNF levels will be higher, and cognition will be improved in executive function, visuospatial memory, and working memory in the NaHCO3 condition due to higher plasma lactate during exercise compared to placebo.

Inclusion Criteria:

• Between the ages of 18-35 years old.
• Perform ≥150 minutes of moderate-to-vigorous aerobic activity per week.

Exclusion Criteria:

• Diagnosis of Type 2 Diabetes.
• Presence of hypoglycaemia.
• History of concussion(s) with persistent symptoms.
• History of mental health conditions.
• History of cardiovascular events requiring hospitalization (e.g., heart attack).
• Pre-existing injuries that prevent completion of aerobic exercise.
• Presence of colour-blindness.

The investigators will share individual patient data (de-identified) with researchers upon request.

Beginning 12 months and ending 36 months following article publication.

Anyone who wishes to access the data.