PROJECT SUMMARY
Rates of cognitive impairment and dementia are on the rise with incidence set to triple by 2050. Mid-life is
an important time for prevention strategies, as around 30% of cognitive impairment has been attributed to
modifiable risk factors at this life stage. Furthermore, adults with cardiovascular disease (CVD) are at even
higher risk of cognitive decline, which is further accelerated by a cardiac-related event. Cerebral
hypoperfusion (reduced brain blood flow) appears to be a significant contributor to cognitive decline, which
can occur as a result of vascular dysfunction and impairment of cerebral blood flow (CBF) regulation. In
contrast, higher cardiorespiratory fitness shows protection against cognitive decline, brain atrophy, and
reductions in CBF. Therefore, strategies that improve vascular function, cardiorespiratory fitness, and other
modifiable CVD risk factors, such as exercise, should be further investigated as prevention strategies in
mid-life adults at high risk of cognitive decline.
Cardiac rehabilitation (exercise and risk factor modification program) may provide an ideal preventative
strategy to attenuate the cognitive decline in mid-life adults who have had a cardiac-related event.
Furthermore, in patients attending cardiac rehabilitation, high intensity interval training (HIIT) has been
shown to double improvements in cardiorespiratory fitness and vascular function, compared with moderate
intensity continuous training (MICT). Whether these greater improvements translate into greater
improvements for cerebrovascular function, CBF regulation, and cognitive function is unknown.
This randomized controlled trial involving mid-life adults with CVD, will investigate the effect of exercise
intensity (HIIT compared with MICT) during a 12-week cardiac rehabilitation (3 sessions/week) on CBF
regulation and cognitive function. We hypothesize that HIIT during cardiac rehabilitation will lead to greater
improvements in CBF regulation (as cerebrovascular reactivity) than MICT, and as a result we hypothesize
that HIIT will lead to greater improvements in cognitive function compared with MICT. Furthermore, this study
will include an observational control group of patients who decline cardiac rehabilitation, to investigate the
potential benefit for exercise-based cardiac rehabilitation compared with no cardiac rehabilitation. We
hypothesize that patients attending exercise-based cardiac rehabilitation will have greater improvements in
CBF regulation (as cerebrovascular reactivity) and cognitive function, compared with patients who do not
attend cardiac rehabilitation. We will also explore changes in resting CBF, brain structure, neurotrophic
biomarkers, and ambulatory blood pressure, as well as other indices of CBF regulation.
This exploratory study will help to generate pilot data that will aid in the design of ongoing research and
proposals for larger grants investigating 1) specific exercise prescription to enhance cognitive health in mid-
life adults, and 2) potential benefits for cardiac rehabilitation participation in this population.
