Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Because of the metabolic changes induced by a physical activity, the hemorheological properties of patients with sickle cell anemia could be further impaired and increase the risks for vaso-occlusive complications. However, few studies suggest that moderate physical activity could be beneficial rather than harmful in patients with sickle cell anemia (SCA). However, the definition of what can be considered as a moderate physical activity in SCA patients is imprecise. The present study tested the effects of a short incremental cycling exercise test conducted until the first ventilatory threshold on different biomarkers. Hematological and hemorheological parameters were compared between 8 patients with SCA and 13 healthy subjects (CONT) before, immediately after the end of the exercise and at 12, 36 and 60 hours after the exercise. We observed no significant hematological or hemorheological alteration induced by the exercise in the two groups. However, the exercise resulted in a delayed improvement of the red blood cell disaggregation threshold at 36 and 60 hrs after exercise in the SCA group which was paralleled to the decrease in the platelet count in this group. The present study suggests that such an exercise might be beneficial for microcirculatory blood flow.
ISSN: 1386-0291

hal-01137567
https://hal.univ-antilles.fr/hal-01137567

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Purpose: The aim of this study was to clarify whether exercising in a tropical climate induces blood rheology alterations despite ad libitum hydration. Methods: Hematological, biochemical and hemorheological changes were investigated in young healthy adults (N = 9 men, 20.7 ± 0.8 yrs) after a 10-km race in hot and humid conditions. Subjects' maximal aerobic abilities were tested using a maximal ramp exercise. Blood was sampled at rest (T R), at the end of the race (T Ex), and after 24 hours of recovery (T 24). Ad libitum hydra-tion was allowed during the race. Blood viscosity (b), red blood cell deformability (EI), aggregation (AI) and disaggregation shear rate (␥) were measured. Results: Hematocrit, hemoglobin and plasma concentration of chlorine, sodium and potassium did not change in response to exercise. No functional consequence was observed on RBC deformability since EI remained unchanged. Percentages of echinocytes, schizocytes and stomatocytes remained in the subclinical range at all times. AI, µ and ßb did not present change. Conclusion: Running exercise in tropical climate with ad libitum hydration does not alter the main rheological properties of blood.
ISSN: 1386-0291

hal-01163975
https://hal.univ-antilles.fr/hal-01163975
DOI : 10.3233/CH-2011-1388

Éditeur(s) : HAL CCSD IOS Press
Résumé : The main objectives of the present work were to test the effects of heat stress on blood rheology and to determine whether the responses can change according to the pig breeds. Thirty-six pigs from three pig's lines (n = 12 for each line) with assumed different tolerance to heat stress were compared: Large White (LW, little tolerance), Creole (CR, good tolerance) and LW × CR pigs (produced from a cross between LW and CR lines). In a first period, all pigs were exposed to a 9-d period of thermo-neutral environment (24°C; d-9 to d-1; P0). At the end of P0, six pigs from each line were slaughtered (n = 18). Then in a second period, the remaining pigs (6/breed; n = 18) were exposed to a 5-d period of heat stress (32°C; d + 1 -d + 5; P1) and thereafter slaughtered at d + 5. Rectal and skin temperatures, as well as respiratory rate, were recorded on d-1 and d + 5. At slaughter, blood was sampled for hematological and hemorheological measurements. Heat stress caused a rise of the skin temperature and respiratory rate without any changes in the rectal temperature or on the hematological and hemorheological parameters when all pigs' lines were considered. We observed a pig line effect on blood viscosity at high shear rate (375 s-1) and red blood cell deformability at 30 Pa with CR pigs having lower blood viscosity and higher red blood cell deformability than LW pigs. While the changes of blood viscosity under heat stress did not reach statistical significance in LW and CR lines, blood viscosity (at 375 s-1) increased above the temperate values in the LW × CR line. Red blood cell deformability at 30 Pa was higher in CR pigs exposed to heat stress compared to LW pigs in the same condition. In conclusion, thermal loading caused physiological stress but did not widely change the hematological and hemorheological profiles. Although some blood rheological parameters seem to vary with the pig breeds, the responses to heat stress are very similar.
ISSN: 1386-0291

hal-01210926
https://hal.archives-ouvertes.fr/hal-01210926
DOI : 10.3233/CH-131722
PRODINRA : 286489
PUBMED : 23603327