Niama Diop Sall

Effects of hydration and water deprivation on blood viscosity during a soccer game in sickle cell trait carriers

The present study compared the changes in blood viscosity, hydration status, body temperature and heart rate between a group of sickle cell trait (SCT) carriers and a control (Cont) group before and after a soccer game performed in two conditions: one with water offered ad libitum (hydration condition; Hyd) and the other one without water (dehydration condition; Dehyd). Blood viscosity and haematocrit per blood viscosity ratio (HVR; an index of red blood cell oxygen transport effectiveness) were measured before and at the end of each game. Resting blood viscosity was greater in the SCT carriers than in the Cont group. The increase of blood viscosity over baseline at the end of the game in the Cont group was similar in the two conditions. In contrast, the change in blood viscosity occurring in SCT carriers during soccer games was dependant on the experimental condition: (1) in Dehyd condition, blood viscosity rose over baseline; (2) in Hyd condition, blood viscosity decreased below resting level reaching Cont values. The Cont group had higher HVR than SCT carriers at rest. HVR remained unchanged in the Cont group at the end of the games, whatever the experimental condition. Although HVR of SCT carriers decreased below baseline at the end of the game performed in Dehyd condition, it increased over resting level in Hyd condition reaching the values of the Cont group. Our study demonstrated that ad libitum hydration in exercising SCT carriers normalises the blood hyperviscosity.

Moderate endurance exercise is not a risk for rhabdomyolysis or renal failure in sickle cell trait carriers

This study tested the hypothesis that trained sickle cell trait (SCT) carriers are not subjected to greater risk of rhabdomyolysis or renal failure in response to moderate submaximal exercise than subjects with normal hemoglobin (CONT). Blood markers in 11 trained SCT carriers and 12 control counterparts were measured before and after 40 min of exercise at 55% of peak power output (Ppeak) conducted in thermoneutral environment. Body weights decreased with exercise in the same proportion in the two groups (from 65.1 ± 7.0 kg to 64.1 ± 7.0 kg and from 70.2 ± 6.6 to 68.6 ± 6.6 kg at the end of exercise in SCT and CONT, respectively). Heart rate and rectal temperature increased in the two groups in response to exercise, but the groups remained closely matched. Serum urea, CRP, CK and LDH were similar in the two groups and remained unchanged in response to exercise. Creatinine, Na(+), K(+), Cl(-) and myoglobin concentrations increased above baseline in response to exercise, with changes of the same magnitude in the two groups. In summary, the results of the present study suggest that moderate submaximal exercise is not unsafe from a biochemical point of view for sportsmen carrying SCT.

Intraday blood rheological changes induced by Ramadan fasting in sickle cell trait carriers.

The goal of the present study was to test whether fasting during the holy period of Ramadan may disturb blood rheology in sickle cell trait (SCT) carriers more than in a group of subjects with normal hemoglobin. Twenty African male students participated in the study: 10 SCT carriers and 10 subjects with normal hemoglobin (CONT). Biochemical parameters (plasma glucose and lipids levels), hematocrit, blood viscosity, and urine specific gravity were measured in the two groups on the 14th day of the Ramadan period (Ramadan condition) and 6 wks after the end of Ramadan (baseline condition). All the measurements were performed twice for each experimental day to measure intraday variation: 8:00 and 18:00 h. Plasma glucose level and lipid profile were not significantly different between the two groups. Although Ramadan did not affect the lipid profile, the plasma glucose concentration was lower during the Ramadan period compared with the baseline condition in the two groups. Hematocrit and urine specific gravity did not differ between the two groups and was greater in the evening than in the morning, independently of the condition. SCT carriers had higher blood viscosity than the CONT group. However, whereas blood viscosity remained unchanged through the day in the CONT group, whatever the condition, SCT carriers were characterized by a large increase of blood viscosity in the evening during the Ramadan period, indicating higher risk for microcirculatory blood flow impairments. Specific medical recommendations are needed for SCT carriers engaged in religious fasting.

[Evaluation of erythrocyte deformability in subjects with sickle cell trait during a soccer game: effect of hydration ad libitum].

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.

Évaluation de la déformabilité érythrocytaire des sujets porteurs de trait drépanocytaire au cours d’un match de football : effet de l’hydratation ad libitum

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.

Évaluation de la déformabilité érythrocytaire des sujets porteurs de trait drépanocytaire au cours d'un match de football : effet de l'hydratation ad libitum Evaluation of erythrocyte deformability in subjects with sickle cell trait during a soccer game: effect of hydration ad libitum

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.