H/A: Physical Activity (2009)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of this study was to determine what level of association exists between physical activity and CD4+ cell counts and HIV-RNA viral load in HIV-infected individuals.

Inclusion Criteria:
  • HIV-positive
  • 18 years of age or older
  • Able to read and understand English at a sixth-grade level
  • Receiving care at the investigator's referring clinic.
Exclusion Criteria:

None listed.

Description of Study Protocol:


Subjects were recruited with the use of flyers and through a referring medical doctor


  • Cross-sectional; descriptive, correlational
  • Convenience sample; subjects were selected from the pool of HIV-infected individuals being treated at a local hospital.

Blinding used (if applicable)

Not stated; implied for laboratory measurements

Intervention (if applicable)

Statistical Analysis

Strength of association between variables of interest was evaluated using Pearson's correlation.

Data Collection Summary:

Timing of Measurements

  • All laboratory results were less than 12 weeks old
  • Three days of measurement of physical activity with a wrist actigraph.

Dependent Variables

Measured by wrist actigraphy (Ambulatory Monitoring, Inc., Ardsley, NY) on the non-dominant hand for three days. Test-retest reliability was high (r=0.98).

  • Physical activity index: Calculated as the percentage of time units where activity levels were recorded at greater than zero
  • Mean physical activity: Calculated as the average minutes of physical activity performed per day over the data collection period
  • Acceleration index: A measure of physical activity intensity.

The following surveys were also administered:

  • Pittsburgh Sleep Quality Index
  • Epworth Daytime Sleepiness Scale
  • Piper Fatigue Scale
  • State-Trait Anxiety Index
  • Perceived Stress Scale.

Independent Variables

CD4+ counts and HIV-RNA loads were obtained from health care providers through retrospective chart review

Control Variables

None listed

Description of Actual Data Sample:

Initial N

66 male and female subjects

Attrition (final N)



39±8 years


  • African American 92%
  • Caucasian 5%
  • Hispanics 3%.

Representative of the HIV-infected population of the study location

Other relevant demographics

None listed


All subjects were on anti-retroviral medications (type was not listed)


Columbia, South Carolina

Summary of Results:


  Physical Activity Index Mean Physical Activity Acceleration Index
HIV-RNA viral load

r= -0.425*

r= -0.318**


CD4+ cell count




*P<0.01; **P<0.05

Other Findings

  • Mean CD4+ cell count: 412±271; range = 8 to 1,140
  • Viral load: 38,571±84,437; range undetectable to 5160,000 viral copies
  • Average minutes of physical activity: 144±31 minutes per day; range 43 to 193 minutes; low, moderate and high intensity activities are all included in this value
  • Physical activity index averaged 84±8.4% and acceleration index averaged -0.22.
  • Physical activity index and mean physical activity levels were not associated with symptom severity, sleep quality, daytime sleepiness, fatigue, state anxiety, trait anxiety and perceived stress
  • A significant inverse relationship was found between mean physical activity level and viral load (P=0.047)
  • A significant inverse relationship was also observed between physical activity index and viral load (P=0.0061)
  • Neither mean physical activity nor physical activity index scores correlated with CD4+ cell counts
  • Acceleration index, a measure of physical activity intensity, showed no correlation to viral load or CD4+ cell counts.
Author Conclusion:
  • This study demonstrates that physical activity, independent of intensity and stage of illness, is inversely associated with HIV-RNA vial load values
  • Data suggests that people participating in more physical activity have lower viral loads
  • The current study demonstrates that regular physical activity may also be beneficial for HIV patients.
Funding Source:
Foundation associated with industry:
Reviewer Comments:

Limitation as stated by authors: Design which does not allow for determination of a causal relationship.

Reviewer comments: Not stated how many men and how many women participated, just the total number of participants; did not state the types of medications the participants were on; no anthropometrics were given, thus there is no indication if subjects were under- or overweight.

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes