PhD Thesis Research Proposals Seminar Event as iCalendar

(Science Event Tags, Exercise Sciences)

18 April 2018

12 - 2pm

Venue: Room 902-402

Location: Newmarket Campus, University of Auckland

Host: Exercise Sciences

Cost: Free

Contact email: exercise-sciences@auckland.ac.nz

Ellie Rickman

Characterisation of Aerobic Capacity and Skin Microvascular Reactivity in Adults With and Without Ischemic Heart Disease

12:00 - 1:00 pm | Room 902-402

Abstract

Skin blood flow (SkBF) is dynamically adjusted over a wide range in response to physiological stimuli.

Blood flow through the skin and other microvascular beds is tightly regulated by neurogenic, endothelial, metabolic and myogenic mechanisms that serve to alter (increase or decrease) vascular diameter, in order to regulate tissue blood flow.

Physical inactivity and low peak aerobic capacity (V̇O2peak) are associated with an increased risk for development of ischemic heart disease (IHD).

IHD is associated with systemic vascular inflammation and oxidative stress that disrupt regulatory mechanisms that control microvascular tone (e.g. endothelial cells).

This leads to disruption in microvascular blood flow and subsequent tissue perfusion.

Given the role of the microvasculature in facilitating nutrient exchange, including both oxygen delivery and carbon dioxide removal, it is critical that microvascular blood flow is adequately regulated; especially during a high metabolic rate activity such as exercise.

Since the skin shares many of the same regulatory mechanisms to control microvascular tone, and these same mechanisms are affected by IHD, the skin may be a useful surrogate for studying microcirculatory dysfunction found in other tissue beds (e.g., cardiac muscle).

The mortality and morbidity rates associated with IHD can be reduced through participation in regular aerobic exercise training that improves peak aerobic capacity.

Aerobically trained adults have greater endothelial-mediated increases in SkBF compared to age-matched untrained adults.

Furthermore, endothelial-mediated vasodilation in the skin microvasculature can be improved along with peak aerobic capacity in sedentary adults that undertake aerobic training.

It is not known if similar improvement in skin microvascular endothelial-mediated dilation occurs with aerobic training in clinical populations known to have compromised microvascular regulation (e.g., IHD).

Therefore, the relationship between SkBF, microvascular endothelial function, peak aerobic capacity and aerobic training remain unclear  in adults with IHD.

Accordingly, the proposed thesis will examine the relationship between skin microvascular regulation and peak aerobic capacity in older adults with and without IHD to provide better understanding of the plasticity of regulatory mechanisms within the microvasculature in health and disease.

Nikita Sloane

The Effects of Cardiovascular Disease and Exercise Training on Exercise Capacity and Cardiovascular Function and Regulation during Exercise in Middle-Aged and Older Women

1:00 - 2:00 pm | Room 902-402

Abstract

Cardiovascular disease (CVD) is a significant health issue in New Zealand women, with more than 75,000 currently living with CVD. While not widely publicised, CVD is the leading cause of mortality in New Zealand women, accounting for more than 3000 lives annually.

Exercise capacity as indicated by peak oxygen uptake (V̇O2peak), is strongly associated with quality of life, functional independence, and all-cause mortality in people with CVD.

Despite several reports of a very low V̇O2peak in women with CVD, there is scarce information on the physiological mechanisms that limit exercise capacity in this patient population.

Moreover, examinations into how exercise training may improve exercise capacity and cardiovascular function and regulation in women with CVD are rare, which consequently limits the development of exercise-based therapeutic strategies.

This research aims to examine the effects of CVD and relatively short-term exercise training on exercise capacity, and cardiovascular function and regulation at rest and during exercise in middle-aged and older women (50-80 years).

To achieve this aim, V̇O2peak and indices of left ventricular function and lower and upper limb blood flow and dilatory capacity at rest and exercise will be assessed in women with and without CVD prior and after a 16-week, multimodal exercise training programme.

The findings of this research may have significant clinical utility by providing a greater insight into the mechanism(s) contributing to exercise function during acute exercise and in response to exercise training in women with CVD.