Strength Training Improves Insulin Sensitivity and Reduces Body Fat in HIV Positive Patients with Lipodystrophy

By Liz Highleyman

Metabolic complications including insulin resistance and body fat changes (lipodystrophy) are a concern for people with HIV receiving antiretroviral therapy, but the best way to manage these problems remains unclear.

As reported in the October 2008 Journal of Clinical Endocrinology and Metabolism, Danish researchers conducted a study to evaluate the effects of strength training and endurance exercise on insulin sensitivity and fat distribution in HIV-infected patients with lipodystrophy.

A total of 20 previously sedentary HIV positive men with lipodystrophy were randomly assigned to undergo supervised strength training (focused on weight lifting) or endurance training (cardiovascular exercise such as running or bicycling) 3 times weekly for 16 weeks. Participants had peripheral lipoatrophy (fat loss in the face, limbs, or buttocks) plus other lipodystrophy symptoms including abdominal fat gain, elevated blood cholesterol, or reduced insulin sensitivity. Body mass index, however, was within the normal range.

The primary endpoints were improved insulin sensitivity (using the euglycemic-hyperinsulinemic clamp method combined with isotope-tracer infusion) and body fat composition (determined by DEXA scans). Secondary endpoints included fasting lipid levels and inflammatory markers.

Results

• Insulin-mediated glucose uptake increased with both strength training (from 49.0 to 57.8 mcmol glucose/kg lean mass/min; P=0.005) and endurance training (from 55.7 to 63.0 mcmol glucose/kg lean mass/min; P=0.02).

• However, only strength training increased total lean body mass (by 2.1 kg), and decreased total fat (3.3 kg), trunk fat (by 2.5 kg), and limb fat (by 0.75 kg).

• Strength training decreased total fat and limb fat mass to a significantly larger extent than endurance training (P < 0.05).

• Endurance training was associated with reduced levels of total cholesterol, low-density lipoprotein (LDL or "bad") cholesterol, free fatty acids (FFAs), high-sensitivity C-reactive protein, interleukin 6 (IL-6), IL-18, and tumor necrosis factor alpha (TNF-alpha), but increased high-density lipoprotein (HDL or "good") cholesterol (P < 0.05 for all measurements).

• Strength training was associated with decreased triglycerides, FFAs, and IL-18, and increased HDL cholesterol (P < 0.05 for all measurements).

In conclusion, the investigators wrote, "This study demonstrates that both strength and endurance training improve peripheral insulin sensitivity, whereas only strength training reduces total body fat in HIV-infected patients with lipodystrophy."

The investigators suggested that HIV positive people with lipodystrophy would benefit from both types of exercise. However, the further loss of limb fat in individuals who started with lipoatrophy at baseline remains a concern.

Centre of Inflammation and Metabolism at the Department of Infectious Diseases; the Copenhagen Muscle Research Centre; the Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark; and the Department of Mathematical Sciences, University of Copenhagen, Denmark.

10/17/08

Reference
B Lindegaard, T Hansen, T Hvid, and others. The effect of strength and endurance training on insulin sensitivity and fat distribution in HIV-infected patients with lipodystrophy. Journal of Clinical Endocrinology and Metabolism 93(10): 3860-3869. October 2008. (Abstract).