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Erythrocyte sickling during exercise and thermal stress.

Abstract

OBJECTIVE

To examine effects of exercise in the heat and fluid intake on erythrocyte sickling and neutrophil activation in carriers of sickle cell trait (HbAS).

DESIGN, SETTING, AND PARTICIPANTS

Six African American men (2 HbAS; 42% HbS, 4 HbAA; 20.7 +/- 0.8 years; 87.4 +/- 9.6 kg) participated in 2 randomized sessions (separate days) each consisting of 45 minutes of brisk walking (treadmill) in a hot (33 degrees C) environment.

INTERVENTION

Subjects consumed no fluids or fluid for 3 hours prior to (ad libitum) and during (1.02 L) testing.

MAIN OUTCOME MEASUREMENTS

Core temperature, heart rate, and perceived exertion were measured. Forearm venous blood was analyzed for percent erythrocyte sickling and plasma myeloperoxidase.

RESULTS

Time-averaged heart rate (126.6 +/- 5.7 vs. 146.7 +/- 5.9 bpm; P = 0.02) and core temperature (37.6 +/- 0.1 vs. 38.1 +/- 0.1 degrees C; P < 0.05) responses were lower during fluid versus no fluid, with no statistically significant difference in perceived exertion (12.3 +/- 0.5 vs. 13.6 +/- 0.4; P = 0.06). Erythrocyte sickling progressively increased (to 3.5%-5.5%) for HbAS carriers during no fluid exercise only. No sickling was detected in HbAA subjects. Plasma myeloperoxidase responses to exercise were greater (P = 0.03) in HbAS versus HbAA.

CONCLUSIONS

Fluid ingestion at a rate sufficient to offset a body weight deficit can effectively reduce erythrocyte sickling during exercise in the heat.

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    MeSH

    Adult
    African Americans
    Body Temperature Regulation
    Case-Control Studies
    Erythrocytes, Abnormal
    Exercise
    Heart Rate
    Heterozygote
    Hot Temperature
    Humans
    Male
    Oxygen Consumption
    Physical Endurance
    Physical Exertion
    Reference Values
    Risk Assessment
    Sensitivity and Specificity
    Sickle Cell Trait
    Stress, Physiological

    Pub Type(s)

    Comparative Study
    Journal Article

    Language

    eng

    PubMed ID

    15523207

    Citation

    TY - JOUR T1 - Erythrocyte sickling during exercise and thermal stress. AU - Bergeron,Michael F, AU - Cannon,Joseph G, AU - Hall,Elaina L, AU - Kutlar,Abdullah, PY - 2004/11/4/pubmed PY - 2005/3/23/medline PY - 2004/11/4/entrez SP - 354 EP - 6 JF - Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine JO - Clin J Sport Med VL - 14 IS - 6 N2 - OBJECTIVE: To examine effects of exercise in the heat and fluid intake on erythrocyte sickling and neutrophil activation in carriers of sickle cell trait (HbAS). DESIGN, SETTING, AND PARTICIPANTS: Six African American men (2 HbAS; 42% HbS, 4 HbAA; 20.7 +/- 0.8 years; 87.4 +/- 9.6 kg) participated in 2 randomized sessions (separate days) each consisting of 45 minutes of brisk walking (treadmill) in a hot (33 degrees C) environment. INTERVENTION: Subjects consumed no fluids or fluid for 3 hours prior to (ad libitum) and during (1.02 L) testing. MAIN OUTCOME MEASUREMENTS: Core temperature, heart rate, and perceived exertion were measured. Forearm venous blood was analyzed for percent erythrocyte sickling and plasma myeloperoxidase. RESULTS: Time-averaged heart rate (126.6 +/- 5.7 vs. 146.7 +/- 5.9 bpm; P = 0.02) and core temperature (37.6 +/- 0.1 vs. 38.1 +/- 0.1 degrees C; P < 0.05) responses were lower during fluid versus no fluid, with no statistically significant difference in perceived exertion (12.3 +/- 0.5 vs. 13.6 +/- 0.4; P = 0.06). Erythrocyte sickling progressively increased (to 3.5%-5.5%) for HbAS carriers during no fluid exercise only. No sickling was detected in HbAA subjects. Plasma myeloperoxidase responses to exercise were greater (P = 0.03) in HbAS versus HbAA. CONCLUSIONS: Fluid ingestion at a rate sufficient to offset a body weight deficit can effectively reduce erythrocyte sickling during exercise in the heat. SN - 1050-642X UR - https://www.unboundmedicine.com/medline/citation/15523207/full_citation L2 - http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=1050-642X&amp;volume=14&amp;issue=6&amp;spage=354 ER -