Cardiorespiratory responses during three repeated incremental exercise tests in sickle cell trait carriers

Area of Science:

• Exercise Physiology
• Hematology
• Cardiorespiratory Fitness

Background:

• Sickle cell trait (SCT) is a common inherited blood disorder.
• Understanding the physiological responses to exercise in SCT carriers is crucial for health and performance.
• Previous research has not fully elucidated cardioventilatory adaptations during repeated strenuous exercise in SCT carriers.

Purpose of the Study:

• To investigate and compare cardioventilatory responses during incremental exercise tests (Iet) between sickle cell trait carriers (SCTc) and control subjects.
• To assess the impact of repeated exercise bouts on exercise performance in both groups.

Main Methods:

• Eight SCTc and six control subjects underwent three incremental exercise tests (Iet) with 10-minute recovery periods.
• Cardioventilatory parameters, including maximal oxygen uptake (VO2max) and ventilatory thresholds, were measured at rest and during the first and third Iet.
• Time course of power output was analyzed across exercise tests.

Main Results:

• No significant differences were found in ventilatory parameters, such as VO2max and ventilatory thresholds, between SCTc and control groups.
• Both groups demonstrated a significant difference in the time course of power output from 80% VO2max to VO2max between the first and third Iet.
• SCTc exhibited normal cardioventilatory responses throughout the repeated exercise tests.

Conclusions:

• Sickle cell trait carriers (SCTc) demonstrate normal cardioventilatory responses during successive incremental exercise tests.
• The presence of HbS in red blood cells does not appear to limit aerobic exercise capacity in SCTc.
• SCTc can tolerate strenuous aerobic exercise without significant cardiorespiratory limitations.