Recent evidences showed that in HIV patients Highly Active Antiretroviral Therapy (HAART) and HIV per se may affect parasympathetic tone; this may increase the cardiovascular risk and contribute to HIV associated lipodystrophy. Such impairment may be reversed by a regular physical activity, which is known to increase vagal tone. PURPOSE: To evaluate vagal tone and its change after 3 months of aerobic training in HIV patients on HAART. METHODS: 12 non-hypertensive and non-smoker patients (F/M 2/10; 47±5 yrs; 71±14 kg) with HIV infection (H) on HAART were enrolled. A group of 12 control (C) subjects (F/M 3/9; 48±12 yrs; 76±13 kg), matched for gender, age and anthropometric features, was enrolled for baseline comparisons. Heart rate variability (HRV) indexes of parasympathetic tone in time (RMSSD, pNN50) and frequency (High Frequency [HF] in absolute and normalized units [nu]) domains, and a HRV index of sympathovagal balance (LF/HF ratio) were calculated in basal condition in H and C subjects, both in supine and standing position for 5 min each, by a HR monitor. The H group was then trained by walking at 60-70% of maximal HR 3 times/week for 12 weeks, and the HRV measures were repeated thereafter. A 6-min walking test (6MWT) was executed before and after the training. RESULTS: In basal condition, despite similar values in supine position between H and C subjects, HIV patients showed a lower parasympathetic tone during standing, which was significant in the linear indexes (RMSSD: H 16.7±5.1 vs C 25.3±10.5 ms [p<0.05]; pNN50: H 1.4±1.3 vs C 5.4±5.3% [p<0.05]; HF: H 180±207 vs C 196±139 ms2; HFnu: H 21.6±23.5 vs C 27.0±16.2), and a higher sympathetic activation (LF/HF: H 9.2±7.0 vs C 4.1±2.7 [p=0.04]) compared to C subjects. Fitwalking® training significantly improved the distance covered by 6MWT (from 667±50 to 802±160 m, p=0.01) and the physical work done (from 451±96 to 538±132 J, p=0.01). However, standing values of HRV indexes did not significantly change after training in H patients (RMSSD 15.2±6.6 ms, pNN50 1.1±1.7%, HF 100±93 ms2, HFnu 11.5±6.7, LF/HF 9.7±7.5; p=ns vs pre-training for all comparisons). CONCLUSIONS: 12-weeks aerobic training improved cardiovascular fitness in HIV patients, but did not affect the heart parasympathetic control, which remained reduced compared to healthy subjects.

Parasympathetic tone and its adaptation to aerobic training (Fitwalking®) in HIV patients on anti-retroviral therapy

G. Merati;
2012

Abstract

Recent evidences showed that in HIV patients Highly Active Antiretroviral Therapy (HAART) and HIV per se may affect parasympathetic tone; this may increase the cardiovascular risk and contribute to HIV associated lipodystrophy. Such impairment may be reversed by a regular physical activity, which is known to increase vagal tone. PURPOSE: To evaluate vagal tone and its change after 3 months of aerobic training in HIV patients on HAART. METHODS: 12 non-hypertensive and non-smoker patients (F/M 2/10; 47±5 yrs; 71±14 kg) with HIV infection (H) on HAART were enrolled. A group of 12 control (C) subjects (F/M 3/9; 48±12 yrs; 76±13 kg), matched for gender, age and anthropometric features, was enrolled for baseline comparisons. Heart rate variability (HRV) indexes of parasympathetic tone in time (RMSSD, pNN50) and frequency (High Frequency [HF] in absolute and normalized units [nu]) domains, and a HRV index of sympathovagal balance (LF/HF ratio) were calculated in basal condition in H and C subjects, both in supine and standing position for 5 min each, by a HR monitor. The H group was then trained by walking at 60-70% of maximal HR 3 times/week for 12 weeks, and the HRV measures were repeated thereafter. A 6-min walking test (6MWT) was executed before and after the training. RESULTS: In basal condition, despite similar values in supine position between H and C subjects, HIV patients showed a lower parasympathetic tone during standing, which was significant in the linear indexes (RMSSD: H 16.7±5.1 vs C 25.3±10.5 ms [p<0.05]; pNN50: H 1.4±1.3 vs C 5.4±5.3% [p<0.05]; HF: H 180±207 vs C 196±139 ms2; HFnu: H 21.6±23.5 vs C 27.0±16.2), and a higher sympathetic activation (LF/HF: H 9.2±7.0 vs C 4.1±2.7 [p=0.04]) compared to C subjects. Fitwalking® training significantly improved the distance covered by 6MWT (from 667±50 to 802±160 m, p=0.01) and the physical work done (from 451±96 to 538±132 J, p=0.01). However, standing values of HRV indexes did not significantly change after training in H patients (RMSSD 15.2±6.6 ms, pNN50 1.1±1.7%, HF 100±93 ms2, HFnu 11.5±6.7, LF/HF 9.7±7.5; p=ns vs pre-training for all comparisons). CONCLUSIONS: 12-weeks aerobic training improved cardiovascular fitness in HIV patients, but did not affect the heart parasympathetic control, which remained reduced compared to healthy subjects.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11383/2101734
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