DOI: 10.4225/03/5897c6a7668b3
title: Physical activity for people living with the human immunodeficiency virus

description: Highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV) into a chronic, relatively manageable illness for those who can access medical care. Despite increased life expectancy, however, HIV remains a serious illness, as problems associated with the virus and its treatments contribute to a reduced quality of life and a significant burden of disease. Patients face issues of aging and frailty, including an increased risk for the development of cardiovascular disease (CVD) and a range of metabolic, morphological and psychological problems. 
Physiotherapists and other health care providers have advocated for the use of exercise training interventions and increased physical activity participation in HIV infection to help manage many physical and psychological complications. However, the effects of long term physical activity in this context are largely unknown. This Thesis will aim to determine whether long term physical activity is associated with improved health outcomes for people living with HIV and will focus on clinical endpoints relevant to chronic, treated HIV infection. 
Increasing knowledge of patterns of physical activity behaviours in this patient group and understanding factors that may contribute to low levels of physical activity is also important. This knowledge may allow HIV health care providers to target physiotherapy referrals to those who are most likely to benefit from physical activity interventions. Specific strategies can be developed to target interventions and reduce inactivity (and the associated poorer health outcomes). 
The current research was undertaken in five main parts:	
1. Measurement of the prevalence of physical activity in an ambulatory HIV-infected population.
2. Validation of a well recognised physical activity measurement tool for use in HIV-infected populations.
3. A systematic evaluation of existing evidence on the effects of exercise training on morphological and metabolic outcomes in HIV-infected populations.
4. Description of long term physical activity/cardiovascular fitness and an exploration of relationships between long term physical activity/cardiovascular fitness and body composition, body image and CVD risk, in HIV-infected individuals.
5. Evaluation of the relationship of body composition and joint health (knee structure) in HIV-infected individuals.
The description and measurement of physical activity behaviours in populations with chronic, treated HIV infection has been the subject of few studies. The proportion of HIV-infected individuals who meet physical activity recommended guidelines is also unknown. Chapter 2 measured the physical activity prevalence of an ambulatory HIV- infected population and determined the proportion of individuals meeting the Centers for Disease Control (CDC) and the American College of Sports Medicine (ACSM) physical activity guidelines. The majority of HIV-infected participants (73.8%) met recommended physical activity guidelines, however 1:4 participants engaged in suboptimal levels of physical activity.

There is a current lack of practical and reliable physical activity measurement instruments that have been validated for clinical and research purposes in populations with HIV infection. Chapter 3 investigated the validity of the International Physical Activity Questionnaire (IPAQ) long form, a well recognised physical activity measurement tool. The IPAQ long form is a simple, inexpensive, easily to administer questionnaire. It has been extensively used in healthy and disease specific populations, however its application in HIV-infected populations has not previously been evaluated. There was significant correlation between physical activity measured by the IPAQ and accelerometry, however problems of over-reporting and its poor ability to identify inactive individuals are of concern.
To our knowledge, a systematic review on the effects of exercise training on metabolic and morphological complications has not previously been performed.  Chapter 4 represents a systematic review of published randomised controlled trials (RCTs) on the topic and aims to elucidate the latest evidence for the role of exercise interventions in managing these important complications of HIV and its treatment. Few RCTs were found and their quality varied. Aerobic exercise decreased adiposity and improved certain lipid subsets while progressive resistive exercise increased body weight and peripheral limb girths. A combination of both types of training did not provide additional benefits. 
There is a relative lack of data regarding the optimal role of long term physical activity in managing HIV-infected patients in the era of HAART. Chapter 5 aimed to improve our understanding of the relationships between long term physical activity/cardiovascular fitness and important HIV clinical outcomes. Truly evidence-based health recommendations and interventions require knowledge of the effects of sustained, habitual physical activity, as well as an understanding of the determinants of and barriers to participation in physical activity in the relevant patient population. This data will facilitate optimal prescription of physical activity and assist in the future development of evidence-based physical activity guidelines for this group. An improved ability to target patients who could benefit most from physiotherapy intervention has also been achieved. Both physical activity and cardiovascular fitness did not change substantially over one year; however a suboptimal level of physical activity participation was identified. Cardiovascular fitness was associated with improved body composition, while improving physical activity levels were associated with improved perceived body image. Despite convincing evidence that physical activity and cardiovascular fitness are associated with reduced CVD risk in the general population, our findings were inconclusive. Finally, being in a permanent relationship was correlated with higher levels of physical activity. 
The problem of obesity is increasing in the HIV setting and it is a well recognized risk factor for osteoarthritis (OA) in the general population. It is plausible that the morphological complications discussed in Chapter 4, particularly recent problems of obesity, overweight and central fat accumulation observed in HIV- infected individuals may also result in an increased incidence of OA. A rising prevalence of bone health issues, including osteopenia and osteoporosis in the HIV-infected population has recently been observed. Chapter 6 explored a cross sectional sample of HIV-infected individuals and looked at the relationship between body composition and knee structure abnormalities. Total body and android fat mass were inversely related to average knee cartilage volume in ambulant, HAART-treated HIV-infected adults. This Chapter discusses these findings as novel implications for musculoskeletal health of chronic, treated HIV infection. 
This Thesis examined the relationships between long term physical activity/cardiovascular fitness and important HAART-related complications over a one year period. It defined the prevalence of long term physical activity in a local cohort of HIV-infected individuals and validated a well recognised physical activity measurement instrument. Existing RCTs on the effects of exercise training on metabolic and morphological complications were systematically reviewed and the risk of OA in this population is discussed after a novel finding. This Thesis contributed to an increased understanding of the plausible role of both physical activity and exercise training in the optimal management of chronic, treated HIV infection. It has also identified priority areas for future study in this area.