Filling the risk factor gap: How does exercise exert its cardiovascular benefits?

Exercise training has strong and independent cardioprotective effects which are, in part, mediated through a direct effect of exercise training on the vasculature (Green 2009; Green et al. 2008).

More specifically, our team has identified a biphasic adaptive response in large conduit arteries following exercise training in humans, with functional changes preceding structural remodelling (Tinken et al. 2008). These beneficial adaptations appear to be dependent on changes in lumenal blood flow and intimal shear stress (Thijssen et al. 2011; Tinken et al. 2010).

These studies, amongst others, involve the use of high-resolution Doppler ultrasound to directly quantify arterial shear stress as well as changes in function, size and wall thickness of arteries in vivo.

In addition, studies investigating smaller skin blood vessels reveal exercise training (Black et al. 2008) and whole body heating (Carter et al. 2014) enhance microvascular vasodilator function, results which appear to be dependent on repetitive increases in blood flow.

These collective studies highlight the role of blood flow and shear stress as an adaptive stimulus to the whole arterial tree.

As such, acute studies focusing on the role of shear stress, dependent and independent of exercise (Carter et al. 2013; Dawson et al. 2013; Tinken et al. 2009), have sought to determine how such a stimulus can modulate vascular behaviour and how differential shear patterns can alter the direction of the acute vascular change i.e. exposure to retrograde shear rate can negatively affect vascular function (Green et al. 2002; Thijssen et al. 2009).

We aim to further this research on the importance of shear stress, including but not limited to:

• isolating the effect of different shear patterns when accompanied by other systemic stimuli (transmural pressure, sympathetic stimulation)
• shear profiles: shear rate patterns and the role of antegrade versus retrograde flow on function
• shear patterns during exercise in different regional vascular beds
• microvascular adaptations to exercise and heating: role of blood flow

Read more about our exercise research or our cardiovascular research group.

For more background information, see the suggested readings below.