The incidence of obesity in the population is increasing at an alarming rate, with this comes an increased risk of
insulin resistance (IR). Obesity and IR increase an individual’s risk of having a stroke and they have been linked to several
forms of dementia. Stroke and dementia are associated with, or exacerbated by, reduced cerebral blood flow, which
has recently been described in obese patients. In this review we will discuss the effects of obesity on cerebral artery function
and structure. Regarding their function, we will focus on the endothelium and nitric oxide (NO) dependent dilation.
NO dependent dilation is impaired in cerebral arteries from obese rats, and the majority of evidence suggests this is a result
of increased oxidative stress. We will also describe the limited studies showing that inward cerebral artery remodeling
occurs in models of obesity, and that the remodeling is associated with an increase in the damage caused by cerebral
ischemia. We will also discuss some of the more paradoxical findings associated with stroke and obesity, including the
evidence that obesity is a positive factor for stroke survival. Finally we will discuss the evidence that links these changes
in vascular structure and function to cognitive decline and dementia.