Moderate exercise may benefit patients with sickle cell disease
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A moderate-intensity exercise regimen appeared to improve skeletal muscle microvasculature among patients with sickle cell disease, according to results of a randomized trial published in Blood.
The regimen also appeared to partially reverse microvascular deficits frequently observed in these patients.
The study adds to a growing body of research that suggests limited exercise may benefit patients with sickle cell disease, many of whom are told to avoid such activity because of risks for heart problems and vaso-occlusive crises, researchers noted.
“When physical exercise is tailored to be light to moderate in intensity, the risk [for] problems is limited,” Laurent Messonier, PhD, researcher at Université Savoie Mont Blanc in France, said in a press release. “Performed regularly, this type of exercise may induce beneficial muscle microvascular and functional adaptations that improve patients’ physical abilities and quality of life.”
Patients with sickle cell disease can experience severe vaso-occlusive crises and massive intravascular hemolysis, resulting in severe chronic anemia.
“Collectively, anemia and [hemoglobin] desaturation depress oxygen transport to tissues,” Messonier and colleagues wrote. “In accordance with this framework, reduced oxygenation has been observed in resting skeletal muscle as in other tissues like the brain. Importantly, the profound muscle microvascular remodeling of [patients with sickle cell disease] may also contribute to the reduced oxygen delivery to tissues.”
Endurance training has been well-established as an effective way to boost muscle oxygen supply.
Researchers sought to determine whether a moderate-intensity endurance exercise training program would result in growth of the capillary network in skeletal muscle among patients with sickle cell disease. They randomly assigned 40 patients to a personally tailored, moderate-intensity regimen (n = 20) or to continue their normal lifestyle, which included little physical activity beyond daily routines (n = 20).
The training program included three 40-minute cycle ergometer exercise sessions per week for 8 weeks. Each session had an initial warm-up, a constant-load endurance exercise for 30 minutes, a cool down and light stretching.
Researchers tracked circulating oxygen and blood lactate levels, as well as perceived exertion during each exercise session. They also obtained muscle biopsies from participants’ thighs before and after the training period.
The study results included data on 32 participants (median age, 34 years; 53% men) — 15 in the training group and 17 in the nontraining group.
Biopsy results showed a 17% increase in capillary density (P = .003) and an 18% increase in capillaries around a fiber (P = .015) among patients in the training group compared with the nontraining group. Training group participants demonstrated a 23% greater change in capillaries around a fiber in type I muscle fibers (P = .0004), but not in other fiber types. They also had increases in functional surface of exchange between microvessels and muscular tissue compared with those who did not participate in training (P < .0001).
The morphology of capillaries did not differ significantly between the groups.
Study limitations included its short duration and small sample size.
Researchers noted that training participants experienced significant improvements in muscle function and physical ability, with some also reporting better sleep, concentration and social interactions.
“[This study] argues in favor of promotion of endurance exercise training for patients with sickle cell disease,” Messonier said in the release. “However, we need to stay cautious. Before any exercise, people with sickle cell disease should be tested and receive professional guidance on what level of exercise will be safe and appropriate.” – by John DeRosier
Disclosures: The authors report no relevant financial disclosures.
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