The effects of altering skin and core temperature by cold exposure and exercise on substrate mobilization and utilization were examined. Six subjects between the ages of 22-27 years rested and exercised in neutral and cold environments to produce (1)a neutral core and neutral skin temperature, (2)a neutral core and cold skin temperature, and (3)a cold core and cold skin temperature. Free fatty acid (FFA), glucose (GL), lactate (LA), hemoglobin (Hb), and hematocrit (Hct) concentration were measured after 30, 60, and 90 minutes of exposure to three temperature conditions during rest and three conditions during exercise. In addition, heart rate (HR), respiratory quotient (RQ), and oxygen consumption (VO(,2)) were analyzed during the same time period. Analysis of variance(' ) with repeated measures was used to determine the significance of the effects of skin and core temperatures on the variables of interest. The results indicated that FFA, GL, LA, Hb, and Hct, concentration significantly increased during rest when both mean skin temperature (T(,sk)) and rectal temperature (T(,re)) were reduced. Plasma FFA(' ) concentration was also significantly elevated during exercise when both T(,sk) and T(,re) were lowered. No significant differences were observed when(' ) T(,sk) alone reduced. HR decreased and VO(,2) increased during rest when(' ) T(,sk) and T(,re) reduced but during exercise HR was reduced when T(,sk)(' ) alone was lowered. No significant difference was demonstrated between thermoregulatory VO(,2) during exercise and thermoregulatory VO(,2)(' ) during rest when comparing absolute values. However, when comparing the relative changes during each condition, greater increases were observed in thermoregulatory VO(,2) during rest than during exercise. A significant(' ) inverse correlation was observed between thermoregulatory VO(,2) and(' ) the increase in / FFA concentration during rest in the cold when T(,sk) alone(' ) was lowered. RQ values decreased during exercise in the cold when both T(,sk) and T(,re) were reduced. It was concluded that reductions in both T(,sk)(' ) and T(,re) are necessary during cold exposure to produce increases in substrates, hemoconcentration, lactate, and VO(,2). In addition, fat(' ) mobilization and utilization occurs during exercise in the cold only if reductions in both T(,sk) and T(,re) are produced. Light exercise may inhibit(' )the relative increase in thermogenesis during cold exposure but not whencomparing absolute values at a given time period. An inverse relationshipbetween thermogenesis and fat mobilization occurs during rest in the cold(, )when T(,sk) is reduced. / Source: Dissertation Abstracts International, Volume: 42-03, Section: B, page: 0928. / Thesis (Ph.D.)--The Florida State University, 1981.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74449 |
| Contributors | HURLEY, BERNARD F., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 134 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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