Type your tag names separated by a space and hit enter

Determinants of endurance exercise capacity in the heat in prepubertal boys.

Abstract

The goal of this study was to identify factors which limit exercise endurance in hot ambient conditions in prepubertal boys. Eight healthy non-acclimatized, highly physically active prepubertal boys performed steady load cycling at approximately 65 % peak VO (2) to exhaustion in both cool (19.6 +/- 0.6 degrees C, 66.4 +/- 11.0 % relative humidity) and hot (31.0 +/- 0.3 degrees C, 56.9 +/- 2.0 % relative humidity) environmental conditions. Cardiac output, oxygen uptake, rectal temperature (T (re)), rating of perceived exertion (RPE), blood pressure, and calculated arterial venous oxygen difference were obtained serially in each testing session, and percent dehydration was calculated from body weight loss. Endurance time was significantly shorter in the hot condition (29.30 +/- 6.19 minutes versus 41.38 +/- 6.30 minutes in the cool room). No significant differences in circulatory markers or hydration status were observed either during testing or between cycling thermal conditions. Rate of rise of T (re) was greater during exercise in the heat, but no significant difference in T (re) between conditions was observed at exhaustion. Mean values of RPE were consistently greater during exercise in the heat, but these differences did not reach statistical significance. These findings support the concept that rises in core temperature and/or brain perception (RPE) rather than circulatory insufficiency may be the critical factors defining limits to exercise in the heat.

Links

  • Publisher Full Text
  • Authors+Show Affiliations

    ,

    Department of Pediatrics, Baystate Medical Center, Springfield, MA 01106, USA. thomas.rowland@bhs.org

    ,

    Source

    MeSH

    Blood Pressure
    Body Temperature
    Cardiac Output
    Child
    Cold Temperature
    Exercise Test
    Exercise Tolerance
    Heart Rate
    Hot Temperature
    Humans
    Male
    Oxygen
    Oxygen Consumption
    Physical Endurance
    Physical Exertion
    Puberty
    Weight Loss

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    17213963

    Citation

    Rowland, T, et al. "Determinants of Endurance Exercise Capacity in the Heat in Prepubertal Boys." International Journal of Sports Medicine, vol. 28, no. 1, 2007, pp. 26-32.
    Rowland T, Garrison A, Pober D. Determinants of endurance exercise capacity in the heat in prepubertal boys. Int J Sports Med. 2007;28(1):26-32.
    Rowland, T., Garrison, A., & Pober, D. (2007). Determinants of endurance exercise capacity in the heat in prepubertal boys. International Journal of Sports Medicine, 28(1), pp. 26-32.
    Rowland T, Garrison A, Pober D. Determinants of Endurance Exercise Capacity in the Heat in Prepubertal Boys. Int J Sports Med. 2007;28(1):26-32. PubMed PMID: 17213963.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Determinants of endurance exercise capacity in the heat in prepubertal boys. AU - Rowland,T, AU - Garrison,A, AU - Pober,D, PY - 2007/1/11/pubmed PY - 2007/3/21/medline PY - 2007/1/11/entrez SP - 26 EP - 32 JF - International journal of sports medicine JO - Int J Sports Med VL - 28 IS - 1 N2 - The goal of this study was to identify factors which limit exercise endurance in hot ambient conditions in prepubertal boys. Eight healthy non-acclimatized, highly physically active prepubertal boys performed steady load cycling at approximately 65 % peak VO (2) to exhaustion in both cool (19.6 +/- 0.6 degrees C, 66.4 +/- 11.0 % relative humidity) and hot (31.0 +/- 0.3 degrees C, 56.9 +/- 2.0 % relative humidity) environmental conditions. Cardiac output, oxygen uptake, rectal temperature (T (re)), rating of perceived exertion (RPE), blood pressure, and calculated arterial venous oxygen difference were obtained serially in each testing session, and percent dehydration was calculated from body weight loss. Endurance time was significantly shorter in the hot condition (29.30 +/- 6.19 minutes versus 41.38 +/- 6.30 minutes in the cool room). No significant differences in circulatory markers or hydration status were observed either during testing or between cycling thermal conditions. Rate of rise of T (re) was greater during exercise in the heat, but no significant difference in T (re) between conditions was observed at exhaustion. Mean values of RPE were consistently greater during exercise in the heat, but these differences did not reach statistical significance. These findings support the concept that rises in core temperature and/or brain perception (RPE) rather than circulatory insufficiency may be the critical factors defining limits to exercise in the heat. SN - 0172-4622 UR - https://www.unboundmedicine.com/medline/citation/17213963/Determinants_of_endurance_exercise_capacity_in_the_heat_in_prepubertal_boys_ L2 - http://www.thieme-connect.com/DOI/DOI?10.1055/s-2006-924142 DB - PRIME DP - Unbound Medicine ER -