Background: Human Immunodeficiency Virus (HIV) infection is increasingly seen as a complex chronic disease that can impact the physical state of infected people, especially as they currently live longer with Highly Active Antiretroviral Therapy (HAART).For the initiation of this treatment, World Health Organization (WHO) has defined T helper lymphocytes Cluster-of-differentiation 4 (TCD4) limit rates to guide therapeutic decisions. These rates vary according to the pathological contexts and can be 200, 350 or 500 TCD4 cells/mm³. The higher the level of TCD4, the better the quality of life (QoL) of people living with HIV (PLWH). Knowing also that QoL is linked to fitness condition, is there a relationship between TCD4 cells level and fitness condition? Physical adaptation to exercise reflecting cardiorespiratory endurance is a major component of the fitness condition and easily measurable by physical tests such as the submaximal step test. Measuring this component in PLWH will assess a possible relationship between fitness condition and TCD4 cell level.

Purpose:To determine whether or not physical adaptation to exercise is related to TCD4 cells level among PLWH.

Methods:Sixty-six (66) participants (35 males, mean age±SD = 36.59±6.04 years old) were recruited in Benin. Valid multistage step-test procedure was used to determine the index of physical adaptation to exercise (PW65%/kg) and index of the perception of effort to submaximal exercise (RPE65%). Number of stages performed during step-test was noted for each subject. Descriptive statistical analyses were reported as means and standard deviations (SD).Student test was used to compare the groups. We used Pearson's correlation to determine the relationship according to sex between RPE65% and PW65%/kg, between TCD4 rates and PW65%/kg or RPE65%.

Results: Mean±SD of TCD4 rate was 388.70±267.91 cells/mm³ (range: 6 to 1268 cells/mm³).  Mean±SD of PW65%/kg in male group was 5.09±1.50 and 4.32±1.19 in female group with significant difference (t= 2.26; p= 0.02). The comparison of number of stages performed in both groups during step-test showed significant difference (t= 3.72; p < 0.0001).  Pearson's correlation have shown that RPE65% is linked to PW65%/kg in male (r = 0.71; p < 0.0001) and in female (r = 0.61; p < 0.0001). TCD4 rates were not linked to PW65%/kg neither in male (r = 0.17; p = 0.31) nor in female (r = 0.28; p = 0.12). Similarly, no significant relationship was observed between TCD4 rates and RPE65% neither in male (r = 0.20; p = 0.24) nor in female (r = 0.34; p = 0.055).

Conclusion: There seems to be no relationship between TCD4 cells level and physical adaptation to exercise among PLWH.

Implications: This study suggests that the levels of TCD4 cells have no influence on physical adaptation in PLWH and that exercise program can be designed to them under medical control, whatever the levels of TCD4 cells.

Ethics approval: This study was approved by CHUD-OP (N°1610/2014CHD-OP/DIR/SAAE/SAF/SG/DGAP/SA).

Keywords: TCD4 cells, HIV, physical adaptation to exercise.