To the best of our knowledge, this is the first study to investigate the influence of progressive resistance training in HIV-infected people older than 60 years. The training protocol followed the recommendations of American College of Sports and Medicine3
, which suggest a progression model for resistance exercises in healthy, older adults. For this population, the studies show favorable changes regarding the risk factors associated with osteoporosis, heart disease, cancer and diabetes and also show a reduction in fat mass and an increase in lean mass and muscular strength.4,18
As mentioned in the results, only 11 out of 14 HIV-infected people, aged 60 years or more, completed the one-year training period. Among them, those who experienced some intercurrence during the training period did not suffer deconditioning. When they restarted training, it was easy for them to continue with the same loads they used before.
A substantial strength increase was seen for all exercises in every patient who completed the training program regardless of their age, gender, baseline HIV infection stage or the presence of any HIV/AIDS-associated morbidity, and this was not different for the only patient who did not use antiretrovirals. The average increase in the load supported after 12 months of resistance training varied from 74 to 122% (p≤0.003–0.021), depending on the muscular group considered. In addition, the functional tests results, which showed significant improvement in the sit-standing and walking 2.4 m times (p= 0.003), reflected this increase. Before starting the training program, the patients were all sedentary and, in spite of having different baseline HIV infection stages and co-morbidity histories, they had stable clinical conditions. Thus, the strength increase observed could hardly be attributed to any other cause but the training program. The strength increment is important for the quality of life of the aged population because it improves biomechanics and cardiovascular responses, thus facilitating daily life activities.
Our sample was comprised of elderly HIV-positive individuals who were experiencing a stable clinical evolution, almost all of them under HAART treatment for more than one year prior to the beginning of the study. However, despite the significant benefits associated with HAART, HIV infection and its therapy have been associated with the development of several metabolic complications: increased central adiposity, peripheral lipoatrophy, peripheral insulin resistance, diabetes, dyslipidemia and hypertriglyceridemia, osteoporosis and osteopenia. These complications may predispose patients to a premature risk of metabolic and cardiovascular diseases.19
In addition, aging predisposes them to the same biological effects,20
and one could expect that aging could act as a potentiator of those HIV infection- and HAART-related alterations. On the other hand, resistance training improves many of those alterations. 2
In our study, no changes were seen either in body composition, assessed by DEXA after 12 months of resistance training, or in anthropometric measures with the exceptions of triceps (p=0.037) and thigh (p=0.011) skinfolds. Weight did not change significantly (p=0.84) either. We are well aware that this could be simply an effect of the lack of power of the study due to the small size. However, the low intensity of the alterations seen in and the fact that some of them are opposite to what is the expected effect of resistance training could suggest that the absence of statistical significance may be true.
Finally, the effects of exercises on immune function have been studied in both adult and elderly healthy populations, showing that moderate levels of training are helpful for both populations.21,22
In our study, assessment of immune response, which is usually performed for HIV patients, showed a significant increase in both CD4+
counts (Δ=151 cells, p
=0.008) and in the CD4+
ratio (0.63 to 0.81, p
=0.009) in addition to a non-significant increase in the CD8+
counts (Δ =54 cells; p
=0.464) after one year of resistance training. Those are important variations in the number of cells, considering that there were no significant changes in viral load or HAART use among them during the training period. Almost all patients had undetectable viral load and were on HAART therapy before, during and after the training period. Therefore, the observed changes in the numbers of CD4+
cells, together with the absence of new HIV-related morbidity, should most probably be attributed to their stable HIV infection conditions.
In conclusion, despite the relatively small sample, our results indicate that a progressive resistance training program can benefit elderly people living with HIV without any major adverse effects or worsening of HIV/AIDS related conditions, which favors its recommendation for such a population.