Functional aerobic impairment in adolescents seropositive for HIV: a quasiexperimental analysis

Health-Related Physical Fitness Evaluation in HIV-Diagnosed Children and Adolescents: A Scoping Review

BACKGROUND

Health-related physical fitness has been widely used to investigate the adverse effects of HIV infection/ART in children and adolescents. However, methods/protocols and cut-points applied for investigating health-related physical fitness are not clear. The aim of this scoping review was to map the literature to identify gaps in knowledge regarding the methods/protocols and cut-points.

METHODS

A scoping review, following the Joana Briggs Institute (JBI) guidelines, was conducted through ten major databases. Search followed the PCC strategy to construct block of terms related to population (children and adolescents), concept (health-related physical fitness components) and context (HIV infection).

RESULTS

The search resulted in 7545 studies. After duplicate removal, titles and abstracts reading and full text assessment, 246 studies were included in the scoping review. Body composition was the most investigated component (n = 244), followed by muscular strength/endurance (n = 23), cardiorespiratory fitness (n = 15) and flexibility (n = 4). The World Health Organization growth curves, and nationals' surveys were the most reference values applied to classify body composition (n = 149), followed by internal cut-points (n = 30) and cut-points developed through small populations (n = 16). Cardiorespiratory fitness was classified through cut-points from three different assessment batteries, as well as cut-points developed through studies with small populations, muscular strength/endurance and flexibility were classified through the same cut-points from five different assessment batteries.

CONCLUSIONS

The research on muscular strength/endurance, cardiorespiratory fitness and flexibility has been scarcely explored. The lack of studies that investigated method usability as well as reference values was evidenced.

Physical functioning in adolescents with perinatal HIV

Perinatal HIV impacts on growth and development in childhood, with physical impairments such as growth limitations, decreased physical activity, reduced exercise tolerance and cardiopulmonary dysfunction continuing into adolescence. There is limited data on other physical functioning domains in perinatally HIV-infected adolescents (PHIVA) thus the aim of this study was to establish the physical sequelae of perinatal HIV in adolescents. This South African cross-sectional study compared PHIVA with HIV-negative adolescents, assessing anthropometry, muscle strength, endurance and motor performance. All ethical considerations were adhered to. The study included 147 PHIVA and 102 HIV-negative adolescents, aged 10-16 years. The majority (87.1%) of PHIVA were virally suppressed however, they still showed significant deficits in height (p < 0.001), weight (p < 0.001) and BMI (p = 0.004). Both groups performed poorly in muscle strength and endurance but did not differ significantly. In motor performance, the PHIVA scored significantly lower for manual dexterity and balance, with significantly more PHIVA with motor difficulty. A regression analysis showed that viral suppression predicted muscle strength (p = 0.032) and age positively predicted endurance (p = 0.044) and negatively predicated aiming and catching (p = 0.009). In conclusion, PHIVA face growth deficits and challenges with motor performance, especially with manual dexterity and balance.

Association of Diastolic Dysfunction with Reduced Cardiorespiratory Fitness in Adults Living with HIV

Despite the high prevalence of diastolic dysfunction in adults living with HIV, the impact on cardiorespiratory fitness (CRF) is understudied. The objective of this cross-sectional study was to investigate the relationship between cardiac function and CRF in adults with HIV. Adults receiving antiretroviral therapy with no history of coronary artery disease (CAD) or heart failure were eligible to participate. Cardiac function was assessed by resting Doppler echocardiography. CRF was measured by oxygen utilization at peak exercise (VO₂peak). The majority of participants were African American (86%) and male (97%) with a mean [standard deviation (SD)] age of 56.6 (7.1) years and median CD4 lymphocyte count of 492 cells/mL. The mean (SD) VO₂peak was 26.1 (5.5) mL/(kg·min). Age, diabetes, hypertension, and hemoglobin were associated with VO₂peak. Overall, diastolic dysfunction was present in 38% and was associated with lower VO₂peak (p < 0.05). VO₂peak was lower among those with impaired myocardial relaxation (e' <8 cm/s) compared with normal relaxation [mean ± SE mL/(kg·min), 25.2 ± 0.6 vs. 27.7 ± 0.9, p < 0.05]. Adjusted for age and clinical factors, each unit increase in left ventricular relaxation (E/A) was associated with an average 4.4 mL/(kg·min) higher VO₂peak, representing more than one metabolic equivalent. We conclude that diastolic dysfunction is independently associated with clinically significant low CRF in adults with HIV and no history of CAD or heart failure. These results highlight the importance of recognizing diastolic dysfunction in individuals living with HIV regardless of their cardiovascular disease history.

Cardiopulmonary dysfunction in perinatally HIV-infected South African adolescents on antiretroviral therapy: baseline findings from the Cape Town Adolescent Antiretroviral Cohort

INTRODUCTION

Antiretroviral therapy (ART) has reduced morbidity and mortality in sub-Saharan Africa, but the burden of coexistent cardiopulmonary disease in perinatally HIV-positive adolescents on antiretroviral therapy (ART) has not been well described. The aim of this study was to investigate the prevalence and associations of cardiopulmonary dysfunction in adolescents with perinatally acquired HIV on ART.

METHODS

For this cross-sectional analysis, 515 perinatally HIV-positive adolescents ages 9 to 14 years on ART for at least six months, and a comparator group of 110 age-matched HIV-uninfected adolescents were tested between August 2013 and April 2015 using echocardiography, six-minute walk test (6MWT) and spirometry. Those with either abnormal spirometry or abnormal 6MWT and any right or left systolic or diastolic dysfunction or abnormal mean pulmonary arterial pressure were considered as having impaired cardiopulmonary function. Logistic regression was used to investigate determinants of impaired cardiopulmonary function.

RESULTS

Overall, 474 adolescents with perinatally acquired HIV (mean [SD] age, 12 [1.6] years; median [IQR] ART duration, 7 [4.6 to 9.3] years; median [IQR] CD4 count, 712 [571 to 959] cell/mm3 ) and 109 HIV-uninfected adolescents mean (SD) age 11.8 (1.8) years, had successful cardiac and lung function testing. Impaired cardiopulmonary function was detected in 13% of adolescents with perinatally acquired HIV and 8% of HIV-uninfected adolescents, p = 0.136. Among adolescents with perinatally acquired HIV, those with low tricuspid annular plane systolic excursion (TAPSE) had significantly lower mean FEV1 , 1.5 L versus 1.6 L, p = 0.011. Height (OR 0.7, 95%CI 0.5 to 0.9), body mass index (OR 0.7, 95%CI 0.5 to 0.9) and past pulmonary tuberculosis (OR 2.3, 95%CI 1.2 to 4.4) were significantly associated with a low cardiopulmonary function.

CONCLUSIONS

Despite being on ART, cardiopulmonary dysfunction occurs in an appreciable proportion of perinatally HIV-infected adolescents but no significant difference to uninfected controls. This finding requires further exploration. Factors associated with dysfunction may be amenable to public health interventions to reduce cardiopulmonary disease in this population.

Prediction of peak V˙ O2 in Children and Adolescents With HIV From an Incremental Cycle Ergometer Test

PURPOSE

To examine the capacity of physiological variables and performance to predict peak oxygen consumption (peak V˙ O₂) in children and adolescents living with HIV.

METHOD

Sixty-five children and adolescents living with HIV (30 boys) aged 8-15 years, participated in the study. Peak V˙ O₂ was measured by breath-by-breath respiratory exchange during an incremental cycle ergometer until volitional exhaustion. Information on the time to exhaustion, maximal power output (Pmax), and peak heart rate (peak HR) were also recorded.

RESULTS

Predictive models were developed and all equations showed the ability of performance variables to predict peak V˙ O₂. However, Model 1 was based only on Pmax by following equation: Y = 338.8302 + (Pmax [W] * 11.16435), R² = 0.90 and standard error of estimation (SEE) = 180 ml ⋅ min^-1.

CONCLUSION

The V˙ O₂ peak can be predicted simply by the Pmax obtained from the incremental cycle ergometer test. This protocol is a valid and useful tool for monitoring the aerobic fitness of children and adolescents living with HIV, especially in resource-limited settings.

The physical sequelae of perinatally acquired HIV in adolescents: a research proposal

Objectives

As the global access of antiretrovirals for HIV-infected infants improves, so the body of perinatally HIV-infected adolescents (PHIVA) grows. The neurological and physical complications of HIV, both in children and in adults, are well established, however there is a paucity of data pertaining to PHIVA, a group of people who have had a lifetime exposure to the virus and to antiretrovirals. There has been a resounding call for further research in this area, as well as for the development of policies and programmes for this population. The aim of this study is to determine the physical sequelae in PHIVA and to propose a model of care for this population.

Methods

Through interviews with PHIVA, the perceived physical challenges will be established. Thereafter a cohort study with age-matched participants will determine if PHIVA have any limitations in fatigue, endurance, motor function and muscle strength, body mass index, peripheral neuropathy, level of disability and quality of life. Using these results, a model of care will be proposed through the nominal group technique with both PHIVA and clinicians working in HIV and adolescence.

Effects of a 6-week aerobic exercise programme on the cardiovascular parameters, body composition, and quality of life of people living with human immune virus

This study evaluated the effects of aerobic exercise program on the cardiovascular parameters, body composition, and quality of life (QoL) of people living with human immune virus (HIV). Patients were recruited from the HIV clinic in a tertiary hospital in Nigeria. Fish bowl method was used to randomize the patients to either experimental or control group. Experimental group received nutritional counseling and aerobic exercise program on a treadmill, 3 times a week for a period of 6 weeks, while the control group received only nutritional counseling. Cardiovascular parameters, aerobic fitness, body composition parameters, and QoL were evaluated at baseline and 6 weeks. Descriptive statistics was used to explore demographic data while the hypothesis was tested using inferential statistics of t-test. Alpha level was set at P<0.05. The result showed that there was an improvement in cardiovascular parameters in both groups, attaining significance in the experimental group (P=0.000). Aerobic fitness increased significantly in experimental group (P=0.000). Body composition decreased significantly while there was a significant difference in the muscle mass (%) between groups (P<0.05). All domains of QoL had a significant improvement in both groups (P<0.005). A 6-week aerobic exercise program in addition to nutritional counseling was able to significantly improve cardiovascular fitness, body composition, and QoL in people living with HIV/acquired immune deficiency syndrome. Nutritional counseling alone can bring about an improvement only in QoL parameters.

Lung function in HIV-infected children and adolescents

Background

The advent of antiretroviral therapy has led to the improved survival of human immunodeficiency virus (HIV)-infected children to adulthood and to HIV becoming a chronic disease in older children and adolescents. Chronic lung disease is common among HIV-infected adolescents. Lung function measurement may help to delineate the spectrum, pathophysiology and guide therapy for HIV-related chronic lung disease.

Aim

The aim of this study was to review the available data on the spectrum and determinants of lung function abnormalities and the impact of antiretroviral therapy on lung function in perinatally HIV-infected children and adolescents.

Methods

Electronic databases “PUBMED”, “African wide” and “CINAHL” via EBSCO Host, using the MeSH terms “Respiratory function” AND “HIV” OR “Acquired Immunodeficiency Syndrome” AND “Children” OR “Adolescents”, were searched for relevant articles on lung function in HIV-infected children and adolescents. The search was limited to English language articles published between January 1984 and September 2017.

Results

Eighteen articles were identified, which included studies from Africa, the United States of America (USA) and Italy, representing 2051 HIV-infected children and adolescents, 68% on antiretroviral therapy, aged from 50 days to 24 years. Lung function abnormalities showed HIV-infected participants had increased irreversible lower airway expiratory obstruction and reduced functional aerobic impairment on exercise, compared to HIV-uninfected participants. Mosaic attenuation, extent of bronchiectasis, history of previous pulmonary tuberculosis or previous lower respiratory tract infection and cough for more than 1 month were associated with low lung function. Pulmonary function tests in children established on antiretroviral therapy did not show aerobic impairment and had less severe airway obstruction.

Conclusion

There is increasing evidence that HIV-infected children and adolescents have high prevalence of lung function impairment, predominantly irreversible lower airway obstruction and reduced aerobic function.

Effects of a High Protein Food Supplement on Physical Activity, Motor Performance and Health Related Quality of Life of HIV Infected Botswana Children on Anti-Retroviral Therapy (ART)

Objective

Despite existing evidence about the benefits of nutrition, physical activity (PA) and sport to the overall health and wellbeing of children, knowledge gaps remain on this relationship in children living with chronic conditions like HIV/AIDS. Such knowledge should inform context specific programs that could enhance the quality of life of children. The purpose of this study was to examine the effects of integrating a nutrition intervention (culturally tailored food supplement) into antiretroviral therapy (ART) on psychosocial outcomes and physical activity among HIV-positive children in Botswana.

Method

201 HIV-positive children (6–15 years; M = 9.44, SD = 2.40) were recruited and randomly assigned (stratified by age and gender) to two groups. The intervention group (n = 97) received a high protein (bean-sorghum plus micronutrients) food supplement, while the control group (n = 104) received a sorghum plus micronutrients supplement. Participants were followed over 12 months. Anthropometric measures, PA, motor performance, and health related quality of life (HRQL) were collected at baseline, 6 and 12 months.

Results

Mixed repeated-measures ANOVA revealed a significant time effect of the food supplement on target variables except body fat percentage, speed, and school functioning. Time × treatment interaction was found for physical functioning, psychosocial functioning and total quality of life score. Scores on physical functioning and total of quality life in the intervention group significantly increased from baseline to 6 months compared with the control group (p = 0.015).

Conclusion

A combination of ART and nutritional intervention had a positive effect on physical functioning and total quality of life of HIV-positive children in this study. There were also improvements to physical activity and motor performance tests over time. More research is needed on long term effects of nutrition and PA interventions on HRQL in children living with HIV.

Aerobic endurance in HIV-positive young adults and HIV-negative controls in Malawi

BACKGROUND

Aerobic endurance is an important aspect of physical fitness that enables individuals living with HIV to endure in the work place as well as in agricultural operations in order to earn a living and improve their quality of life. However, despite high HIV prevalence rates, the aerobic endurance status of young Malawians living with HIV remains unknown. The objective of this study was to determine the difference in VO2max between HIV-negative and HIV-positive individuals in Blantyre, Malawi.

METHODS

Fifty five participants (17 males and 38 females) who have HIV and were not taking antiretroviral medication and 78 HIV-negative participants (45 males and 33 females) performed the Rockport submaximal treadmill exercise test. Measures of body weight, post-exercise heart rate and time to walk one mile were obtained and used to predict VO2max. Comparisons between groups were adjusted for age differences using analysis of covariance (ANCOVA).

RESULTS

VO2max was significantly lower in HIV-positive subjects [31.1, 28.7 - 33.5mL.kg-1.min-1(mean, 95% CI)] compared with HIV-negative subjects [56.2, 54.3 - 58.1mL.kg-1.min-1].

CONCLUSION

Aerobic endurance was markedly reduced in HIV-positive participants compared with HIV-negative participants. Findings of the current study implicate factors associated with the HIV infection as contributors to a decreased aerobic endurance in people living with HIV.

Management of Sleep Quality and Pain in an Individual Living with HIV and Hepatitis C Coinfection Using an Activity Monitor

STUDY DESIGN

Case report.

BACKGROUND

Twenty-five percent of people living with HIV/AIDS (PLWHA) are also coinfected with hepatitis C virus (HCV). There are limited reports to assist in the symptom management of PLWHA and HCV coinfection.

CASE DESCRIPTION

Our case was a 67-year-old man living with HIV/HCV coinfection and other medical complications. Our intervention consisted of a 6-week progressive conditioning program, while his activity and sleep pattern were monitored using a wrist accelerometer.

OUTCOMES

After completing a conditioning training, there was a 64% decrease in the number of waking episodes per night and 68% decrease in activity at night. Based on Pittsburgh Sleep Quality Index scores, the participant transitioned from being a "poor sleeper" to a "good sleeper." A 40% decrease in pain was reported. Functional outcome measures also showed improvements.

DISCUSSION

There were improvements in the participant's sleep quality and pain. The use of a commercial accelerometer may assist in objectively tracking compliance and activity changes.

Use of the exercise treadmill test for the assessment of cardiac risk markers in adults infected with HIV

BACKGROUND

Despite the association between HIV and coronary artery disease (CAD), there are no specific recommendations for the cardiovascular evaluation of the HIV-infected population. Besides being a tool for the evaluation of CAD, the exercise treadmill test (ETT) provides insights into functional capacity and autonomic function, which have been frequently affected in HIV infection, and thus may be useful in this setting.

METHODS

Forty-nine HIV-infected individuals without known CAD underwent ETT. Peak oxygen consumption during exercise (VO2 peak), functional capacity (in metabolic equivalents [METs]), exercise-induced ischemia, chronotropic incompetence (CI) and abnormal heart rate recovery (HRR) after exercise were studied.

RESULTS

VO2 peak was 31.4±4.8 mL/kg/min and functional capacity was 9.2±1.6 MET. CI was observed in 30.6%, and 10.2% had abnormal HRR. VO2 peak was lower in women and inversely correlated with age and body mass index. None of the patients displayed ischemic changes.

CONCLUSION

Although functional capacity was good, risk markers such as CI and abnormal HRR were not infrequent. This study identifies a subgroup of HIV-infected patients-the older, overweight, or obese-who may have higher risk and deserve cardiovascular screening with the ETT.

Sports behaviour among HIV-infected versus non-infected individuals in a Berlin cohort

Physical activity has been recommended based on beneficial effects described in HIV-infected patients. However, such guidelines do not take into account actual sport behaviours and general attitudes towards physical activity. To evaluate actual sport activity and attitudes towards sport in HIV-infected versus non-infected individuals we conducted an anonymous questionnaire investigating the prevalence, as well as possible changes, in sports engagement and the overall attitude to physical activity. A total of 283 patients of a general care facility specialized in the treatment of HIV/AIDS in Berlin, Germany, participated; 124 were HIV infected and 159 were non-infected, mostly men who have sex with men (MSM) (88%), with a median age of 35 years. The HIV-infected participants had a median CD4+ count of 554 cells/µL and 48.8% of them were using antiretroviral therapy (ART) at the time of survey. The proportion of patients actually performing physical activity was significantly lower (P = 0.028) within the HIV-infected group (61.3%) than within the non-infected group (74.2%). This difference remained significant after accounting for possible confounders such as age, gender, injecting drug use and sexual preferences. Previously reported sport activity prevalence was similar in both groups on leaving school. From our data we could not identify an association between the time of HIV diagnosis and changes in sports activity. In conclusion, fewer HIV-infected individuals report physical activity than non-infected individuals. Sociodemographic studies to evaluate potential differences in sports behaviour are required in order to inform exercise guidelines for HIV-infected patients.

Anaerobic power and muscle strength in human immunodeficiency virus-positive preadolescents

OBJECTIVE

To determine the anaerobic power and muscle strength of preadolescents with human immunodeficiency virus (HIV).

DESIGN

Cross-sectional design.

SETTING

Human performance laboratory at the University District Hospital at the Puerto Rico Medical Center.

PARTICIPANTS

Fifteen preadolescents (8 girls and 7 boys) with a classification of HIV A and B attending an investigational treatment program at the University Pediatric Hospital. Fifteen seronegative control subjects matched by age and gender also were included.

MAIN OUTCOME MEASURES

The power of the lower extremities was measured with use of the Wingate Anaerobic Power Test on a MONARK cycle ergometer (mean power in watts). Local muscle strength of the dominant knee extensors (peak torque/body weight × 100) was tested with an isokinetic dynamometer set at 60 deg/s. Statistical analysis was performed with the Wilcoxon signed-rank test, and statistical significance was accepted at an α level of <.05.

RESULTS

No significant differences between the control group and study group were detected on muscle strength testing. The study group presented a lower anaerobic power (mean power) compared with control subjects (P = .04).

CONCLUSIONS

This exploratory study suggests that HIV-infected preadolescents present lower anaerobic power compared with uninfected control subjects. Our findings of impaired anaerobic capacity can have clinical implications in this population because most of the activities of daily living, such as play, leisure, and sport activities, are short term and high intensity (anaerobic) in nature.

Physical activity and immunity in HIV-infected individuals

The purpose of this study was to determine what relationship exists among physical activity levels and viral load and CD4+ cell count in HIV-infected individuals. Increased viral load is associated with disease progression and symptom severity. A convenience sample of 66 male and female subjects between the ages of 18 and 64 years of age (mean 39 +/- 8) was recruited from a hospital-based HIV/AIDS clinic. Components of PA were assessed for three continuous days using a mini-motion logger wrist actigraph. These components included mean PA level, and PA index and acceleration index. Pearson's correlational analysis was used to test the strength of association between PA components and viral load or CD4+ cell count. A significant inverse relationship was found between mean PA level and viral load (p=0.047). An inverse relationship was also observed between PA index and viral load (p=0.0061). Neither mean PA nor PA index scores correlated with CD4+ cell counts. Acceleration index, a measure of PA intensity, showed no correlation to viral load or CD4+ cell counts. These findings suggest that increasing levels of physical activity might have beneficial effects on viral load in HIV-infected individuals.

Peripheral fatigue: high-energy phosphates and hydrogen ions

Peripheral fatigue results from an overactivity-induced decline in muscle function that originates from non-central nervous system mechanisms. A common symptom of fatigue is a feeling of tiredness or weariness because of overexertion, such as that associated with intense or prolonged physical exercise. Fatigue is worsened by low physical fitness and chronic illnesses. These conditions may intensify fatigue to levels that limit physical and social functioning and severely diminish health-related quality of life. Although etiologic aspects of peripheral fatigue are often associated with regulatory system (neurologic, endocrine, immunologic, muscular) and support system (cardiovascular, pulmonary, metabolic, renal, digestive, skeletal) limitations, final mediation occurs in muscle cells as a result of altered crossbridge functioning. Specifically, the final product and ionic metabolite accumulation that result from adenosine triphosphate hydrolysis appear to inhibit crossbridge formation and activation. Thus, clinical manifestations of peripheral fatigue often can be observed as limitations placed upon muscle or cardiorespiratory endurance, here defined as fatigue resistance. An overview of the common pathways by which peripheral fatigue can be mediated is provided. Product inhibition of contractile chemistry is brought into focus as a common pathway through which the mechanisms of peripheral fatigue often act.

HIV/AIDS e Treinamento Concorrente: a Revisão Sistemática

O uso da terapia anti-retroviral combinada (TARV) aumentou a expectativa de vida dos portadores do vírus da imunodeficiência humana (HIV) e, como conseqüência, torna-se constante o estudo do processo fisiopatológico da infecção e das estratégias de intervenção que possam melhorar a qualidade de vida destes indivíduos. O treinamento concorrente, definido como a associação dos componentes aeróbios e força na mesma sessão de exercícios pode ser inserido neste contexto. O objetivo deste artigo é revisar os aspectos centrais da infecção pelo HIV e as evidências existentes sobre o treinamento concorrente com séries múltiplas e simples nos parâmetros imunológico, virológico, cardiorrespiratório e neuromuscular de pessoas infectadas pelo HIV. O método utilizado foi uma revisão sistemática, com artigos publicados entre 2000-2007, nas bases de dados scielo e pubmed e também em dissertações e teses da biblioteca digital da educação física, esporte e saúde. As evidências científicas encontradas nos 8 estudos analisados indicam que o treinamento concorrente, tanto com séries múltiplas quanto séries simples, melhora os parâmetros cardiorrespiratório e neuromuscular; no entanto, os resultados dos parâmetros imunológico e virológico ainda não estão completamente esclarecidos, principalmente sobre os protocolos com séries simples. Considerando o número restrito de trabalhos apresentados, sugere-se o desenvolvimento de estudos com treinamento concorrente em vários desfechos clínicos para pessoas infectadas pelo HIV.

Prediction of cardiorespiratory fitness in older men infected with the human immunodeficiency virus: clinical factors and value of the six-minute walk distance

OBJECTIVES

To investigate factors related to cardiorespiratory fitness in older human immunodeficiency virus (HIV)-infected patients and to explore the utility of 6-minute walk distance (6-MWD) in measuring fitness.

DESIGN

Cross-sectional study in clinic-based cohort.

SETTING

Veterans Affairs Medical Center, Baltimore, Maryland.

PARTICIPANTS

Forty-three HIV-infected men, median age 57 (range 50-82), without recent acquired immunodeficiency syndrome-related illness and receiving antiretroviral (ARV) therapy.

MEASUREMENTS

Peak oxygen utilization (VO(2)peak) according to treadmill graded exercise testing, 6-MWD, grip strength, quadriceps maximum voluntary isometric contraction, cross-sectional area, muscle quality, and muscle adiposity.

RESULTS

There was a moderate correlation between VO(2)peak (mean +/- SD; 18.4 +/- 5.6 mL/kg per minute) and 6-MWD (514 +/- 91 m) (r=0.60, P<.001). VO(2)peak was lower in subjects with hypertension (16%, P<.01) and moderate anemia (hemoglobin 10-13 gm/dL; 15%, P=.09) than in subjects without these conditions. CD4 cell count (median 356 cells/mL, range 20-1,401) and HIV-1 viral load (84% nondetectable) were not related to VO(2)peak. Among muscle parameters, only grip strength was an independent predictor of VO(2)peak. Estimation of VO(2)peak using linear regression, including age, 6-MWD, grip strength, and hypertension as independent variables, explained 61% of the variance in VO(2)peak.

CONCLUSION

Non-AIDS-related comorbidity predicts cardiorespiratory fitness in older HIV-infected men receiving ARV therapy. The 6-MWD is a valuable measure of fitness in this patient population, but a larger study with diverse subjects is needed.

Moderate intensity exercise training reverses functional aerobic impairment in HIV-infected individuals

HIV infection and HIV drug therapies result in physical and psychological challenges to those living with HIV. These conditions contribute to decreased functional aerobic capacity (FAC). The aim of this study was to determine the effects of a combined moderate-intensity aerobic and resistance exercise intervention on the FAC of HIV-infected individuals. Forty HIV-infected individuals were randomized to an exercise group (EX) who completed six weeks of moderate-intensity exercise training, or to a control group (CON) that did not receive the exercise intervention. Twice weekly, the EX group completed 30 minutes of moderate-intensity aerobic training followed by moderate-intensity resistance training. Prior to, and following, the intervention the FAC for each subject was determined by graded exercise treadmill stress test (GXT). At baseline testing, the mean FAC as determined by treadmill time-based estimation of maximal oxygen consumption was 25% below age-predicted values, a level of reduction indicating the presence of functional aerobic impairment (FAI). Following the intervention, the EX had a significant increase in time to fatigue and estimated VO(2) max (p<.001). Further, FAI was eliminated (1% above age predicted values) during the exercise training. The EX group also experienced decreased heart rates during Stages 1 (p=.02), 2 (p=.01), 4 (p=.05) and 6 (p=.02) of the GXT. The CON had no significant changes during the intervention period. These data indicate that six weeks of combined moderate-intensity aerobic and resistance training can improve FAC and eliminate FAI in those with HIV. Results suggest that the functional limitations common in HIV-infected individuals are due in part to detraining that is reversible through moderate exercise adherence.

Physical activity in a cohort of HIV-positive and HIV-negative injection drug users

Physical activity is beneficial for persons with HIV infection but little is known about the relationships between physical activity, HIV treatment and injection drug use (IDU). This study compared physical activity levels between HIV-negative and HIV-positive injection drug users (IDUs) and between HIV-positive participants not on any treatment and participants on highly active antiretroviral therapy (HAART). Anthropometric measurements were obtained and an interviewer-administered modified Paffenbarger physical activity questionnaire was administered to 324 participants in a sub-study of the AIDS Linked to Intravenous Experiences (ALIVE) cohort, an ongoing study of HIV-negative and HIV-positive IDUs. Generalized linear models were used to obtain univariate means and to adjust for confounding (age, gender, employment and recent IDU). Vigorous activity was lower among HAART participants than HIV-positive participants not on treatment (p=0.0025) and somewhat lower than HIV-negative participants (p=0.11). Injection drug use and viral load were not associated with vigorous activity. Energy expenditure in vigorous activity was also lower among HAART participants than both HIV-negative and HIV-positive participants not on treatment. Thus, HIV-positive participants on HAART spend less time on vigorous activity independent of recent IDU. More research is needed into the reasons and mechanism for the lack of vigorous activities, including behavioral, psychological and physiological reasons.

Reduced aerobic capacity and physical functioning in older HIV-infected men

Aerobic capacity and physical functioning decline with age and chronic illness. The extent of physical disability is unknown in older HIV-infected adults, who represent a rapidly growing proportion of HIV/AIDS patients in the United States. We performed functional performance testing including treadmill testing in 32 HIV-infected male veterans aged 40-69 years. Controls were 47 healthy male subjects tested previously in the same exercise laboratory. HIV-infected subjects were classified as younger (40-49 years, n = 12) or older age (50+ years, n = 20). Peak aerobic capacity (VO2peak) was significantly reduced in the older vs. younger HIV subjects [19.1 mL/kg/min +/- 5.7 (mean, SD) vs. 25.2 +/- 4.2, p = 0.01]. VO2peak was reduced 41% +/- 15% (mean, SD) in HIV-infected subjects compared to expected values from age-matched healthy controls. Regression analyses show a similar decline in VO2peak with age in HIV-infected and healthy controls. Mean 6-min walk distance was not significantly different between the HIV-infected age groups, and was reduced only 8% compared to expected values for healthy adults. Current CD4 count and HAART exposure were similar in the two age groups and were not significantly associated with VO2peak. Anemia (HCT <35%) was significantly associated with reduced VO2peak (p = 0.02), but this association was not independent of the effect of age (p = 0.1). We conclude that older HIV-infected adults have markedly impaired aerobic capacity but maintain the capacity to undertake day-to-day activities. Additional physiologic and metabolic testing is needed to measure the effect of HAART toxicity and primary aging on aerobic capacity, and to determine if older HIV-infected adults are at greater risk.

Anabolic growth hormone action improves submaximal measures of physical performance in patients with HIV-associated wasting

Growth hormone (GH) treatment reverses the muscle loss allegedly responsible for diminished aerobic capacity and increased fatigue in patients with HIV-associated wasting. This study examined whether submaximal measures of physical performance can be used as objective measures of the functional impact of GH treatment-induced anabolism. We randomized 27 HIV-positive men [mean (SD) age, 43.9 (7.2) yr; body mass, 71.9 (10.4) kg; BMI, 23.1 (2.8) kg/m2] with unintentional weight loss despite antiretroviral therapy to receive GH (6 mg) or placebo in a double-blinded, placebo-controlled, cross-over trial with a 3-mo washout. Lean body mass (LBM), maximum oxygen uptake (Vo2 peak), ventilatory threshold (VeT), 6-min walk test (6MWT) distance and work, profile of mood states (POMS) fatigue and vigor scores, and Nottingham health profile (NHP) energy and physical mobility scores were measured. LBM significantly increased after 3 mo of GH treatment vs. placebo (means +/- SE, 3.7 +/- 0.6 vs. 0.3 +/- 0.4 kg; P < 0.001). VeT significantly improved (17.6 +/- 3.7 vs. -5.9 +/- 2.5%; P < 0.001), but Vo2 peak did not change significantly. 6MWT distance improved (24.9 +/- 9.7 vs. 19.9 +/- 11.6 m; P > 0.05) and 6MWT work increased significantly more after 3 mo of GH treatment (33.3 +/- 8.8 vs. 16.5 +/- 7.5 kJ; P < 0.05). POMS scores of fatigue and vigor and the NHP score of energy improved, yet the changes were not statistically significant. GH treatment improved VeT linearly to the increase in LBM (r =0.43, P = 0.037) and 6MWT work (r = 0.51, P = 0.008), and the increase in 6MWT work correlated with increase in LBM (r = 0.45, P = 0.024). Improvement in 6MWT work above the median (27.3 kJ) showed a decrease in fatigue (r = -0.62, P = 0.024). We concluded that GH treatment-induced LBM gains in HIV-associated wasting were functionally relevant, as determined by effort-independent submaximal measures of cardiopulmonary exercise testing.

Growth hormone treatment improves peripheral muscle oxygen extraction-utilization during exercise in patients with human immunodeficiency virus-associated wasting: a randomized controlled trial

The arteriovenous oxygen difference (a-vO(2) difference), a measure of peripheral muscle oxygen extraction-utilization during exercise, is reduced in antiretroviral-treated patients with human immunodeficiency virus (HIV), thus causing a shift in the cardiac output-oxygen consumption (Q-VO(2)) relationship. We investigated the impact of recombinant human GH (rhGH) treatment on a-vO(2) difference and the Q-VO(2) relationship during submaximal exercise by randomizing 12 HIV-infected patients (mean +/- sem: age, 43.3 +/- 1.5 yr; body mass, 69.5 +/- 2.9 kg; body mass index, 22.4 +/- 0.9 kg/m(2); maximum oxygen consumption, 33.6 +/- 1.5 ml/kg x min), with documented unintentional weight loss (>or=10% within the preceding 12 months) despite antiretroviral therapy, to receive 3 months of rhGH (6 mg/d) in a double-blind, placebo-controlled, cross-over trial. We assessed Q (determined noninvasively using CO(2) rebreathing), and subsequently a-vO(2) difference, from Q-VO(2) relationships. At study entry, the mean slope (8.1 +/- 1.0 liters/min x 1-liter increase in VO(2)) and intercept (3.1 +/- 1.3 liters/min), generated from each patient's Q-VO(2) relationship, were greater and lower, respectively, than those reported for healthy individuals (6.0 and 4.0, respectively), thereby indicating a deficit in the a-vO(2) difference. After 3 months of rhGH treatment, the slope decreased to 7.0, and the intercept increased to 3.5. After 1 month of rhGH treatment, the a-vO(2) difference (at a VO(2) of 1250 ml/min) significantly (P < 0.05) increased (17.1 +/- 8.9%) from baseline (9.92 +/- 0.51 ml/dl) and remained elevated (10.39 +/- 0.48 ml/dl) after 3 months of treatment. No significant changes were seen with placebo. Therefore, treatment with rhGH leads to an improvement in peripheral muscle oxygen extraction-utilization and the Q-VO(2) relationship during exercise in patients with HIV-associated wasting despite antiretroviral therapy.

Physiological and psychological effects of exercise interventions in HIV disease

The use of both aerobic and resistance exercise has been shown to improve physiologic parameters such as strength, endurance, time to fatigue, and body composition in the HIV-infected population. Exercise has also been used successfully to treat psychologic conditions such as depression and anxiety that are common in HIV-infected individuals. However, the effects of exercise on immune function in these individuals are uncertain because of conflicting results found among studies. Additionally, many ventures into this area have been attempted with poor research design, resulting in inconclusive evidence or poor generalizability. The focus of this paper is to review the research that has been performed using exercise as an intervention for HIV-infected persons and to determine what needs to be done next to further our understanding of how the HIV-infected body and mind respond to exercise training.

Impaired oxygen on-kinetics in persons with human immunodeficiency virus are not due to highly active antiretroviral therapy

OBJECTIVE

To determine the effects of human immunodeficiency virus (HIV) and highly active antiretroviral therapy (HAART) on oxygen on-kinetics in HIV-positive persons.

DESIGN

Quasi-experimental cross-sectional.

SETTING

Infectious disease clinic and exercise laboratory.

PARTICIPANTS

Referred participants (N=39) included 13 HIV-positive participants taking HAART, 13 HIV-positive participants not taking HAART, and 13 noninfected controls.

INTERVENTIONS

Participants performed 1 submaximal exercise treadmill test below the ventilatory threshold, 1 above the ventilatory threshold, and 1 maximal treadmill exercise test to exhaustion.

MAIN OUTCOME MEASURES

Change in oxygen consumption (Delta.VO2) and oxidative response index (Delta.VO2/mean response time).

RESULTS

Delta.VO2 was significantly lower in both HIV-positive participants taking (946.5+/-68.1mL) and not taking (871.6+/-119.6mL) HAART than in controls (1265.3+/-99.8mL) during submaximal exercise above the ventilatory threshold. The oxidative response index was also significantly lower (P<.05) in HIV-positive participants both taking (15.0+/-1.3mL/s) and not taking (15.1+/-1.7mL/s) HAART than in controls (20.8+/-2.1mL/s) during exercise above the ventilatory threshold.

CONCLUSION

Oxygen on-kinetics during submaximal exercise above the ventilatory threshold was impaired in HIV-positive participants compared with a control group, and it appeared that the attenuated oxygen on-kinetic response was primarily caused by HIV infection rather than HAART.

Decreased peak arteriovenous oxygen difference during treadmill exercise testing in individuals infected with the human immunodeficiency virus

OBJECTIVE

To determine if arteriovenous oxygen difference was lower in asymptomatic individuals with human immunodeficiency virus (HIV) infection than in sedentary but otherwise healthy controls.

DESIGN

Quasi-experimental cross-sectional.

SETTING

Clinical exercise laboratory.

PARTICIPANTS

Fifteen subjects (10 men, 5 women) with HIV and 15 healthy gender- and activity level-matched controls (total N=30).

INTERVENTION

Participants performed an incremental maximal exercise treadmill test to exhaustion. Electrocardiogram, metabolic, and noninvasive cardiac output measurements were evaluated at rest and throughout the tests. Data were analyzed by using analysis of covariance.

MAIN OUTCOME MEASURES

Peak oxygen consumption (Vo(2)), cardiac output, stroke volume, and arteriovenous oxygen difference. The arteriovenous oxygen difference was determined indirectly using the Fick equation.

RESULTS

Peak VO(2) was significantly lower (P<.0005) in participants with HIV (24.6+/-1.2mL.kg(-1).min(-1)) compared with controls (32.0+/-1.2mL.kg(-1).min(-1)). There were no significant intergroup differences in cardiac output or stroke volume at peak exercise. Peak arteriovenous oxygen difference was significantly lower (P<.04) in those infected with HIV (10.8+/-0.5 volume %) than in controls (12.4+/-0.5 volume %).

CONCLUSION

The observed deficit in aerobic capacity in the participants with HIV appeared to be the result of a peripheral tissue oxygen extraction or utilization limitation. In addition to deconditioning, potential mechanisms for this significant attenuation may include HIV infection and inflammation, highly active antiretroviral therapy medication regimens, or a combination of these factors.

A comparison of Qt and a-vO2 in individuals with HIV taking and not taking HAART

PURPOSE

The aim of this study was to determine whether highly active antiretroviral therapy (HAART), rather than the direct effect of HIV infection, limits peripheral muscle oxygen extraction-utilization (a-vO(2)) in individuals infected with the human immunodeficiency virus (HIV).

METHODS

Fifteen subjects (6 female and 9 male) with HIV taking HAART, 15 subjects infected with HIV not taking HAART, and 15 healthy gender and activity level matched non-HIV infected controls (N = 45) performed an maximal treadmill exercise test to exhaustion. Noninvasive cardiac output Qt was measured at each stage and at peak exercise using the indirect Fick method based on the exponential rise carbon dioxide rebreathing method. Intergroup comparisons were adjusted for interactions of peak oxygen consumption ([V02), body surface area, and [V02]t using ANCOVA.

RESULTS

Peak a-vO(2) was significantly lower (P < 0.05) in subjects with HIV taking HAART (10.0 +/- 0.5 vol%) compared with subjects with HIV not taking HAART (11.7 +/- 0.5 vol%) and noninfected controls (12.7 +/- 0.5 vol%). In subjects with HIV taking HAART, peak heart rate (HR) (170.5 +/- 3.9 bpm) was lower than (P < 0.05) and stroke volume (Vs) (123.0 +/- 3.9 mL x beat-1) at peak exercise was higher (P < 0.05) than subjects with HIV not taking HAART (179.9 +/- 3.5 bpm) (106.6 +/- 3.9 mL x beat-1) and noninfected controls (185.4 +/- 3.8 bpm) (100.6 +/- 4.0 mL.beat-1) upon ANCOVA. There were no significant differences in peak [VO2]t between groups.

CONCLUSION

Peak a-vO(2) was diminished in subjects infected with HIV taking HAART compared with HIV-infected subjects not taking HAART and noninfected controls matched for age, gender, and physical activity level. Findings of the current study implicated HAART as a primary contributor to decreased muscle oxygen extraction-utilization in individuals infected with HIV.