Files in this item



application/pdf9329138.pdf (9MB)Restricted to U of Illinois
(no description provided)PDF


Title:Evaluation of Metabolic Energy Expenditure During Prolonged Steady-State Exercise
Author(s):Pogue, Nancy Joan Keal
Doctoral Committee Chair(s):Nelson, R.,
Department / Program:Physiology and Biophysics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Animal Physiology
Abstract:Energy consumed during prolonged steady state exercise was partitioned to radiant, convective and evaporative heat and the energy for climbing and walking. Healthy, non-obese subjects, ages 20 to 35 years, were classified as 5 active males, 5 trained males, 5 active females and 5 trained females. Active subjects ran $$30 mi./wk., had significantly greater VO$\sb{\rm 2max},$ and lower % body fat. Exercise was 45 minutes of treadmill walking at 30% and 60% of VO$\sb{\rm 2max}.$ Energy consumed was measured by indirect calorimetry (IC). Thermographic images were recorded with an infrared radiometer, a mean skin temperature (MST) determined, then heat emitted was calculated with partitional calorimetry equations (ITC). After 30 minutes of exercise, trained groups maintained a lower, more stable MST than active groups, but MST patterns could not be used to classify individuals. Comparing heat loss to pre-exercise values, during exercise radiant heat losses did not change; convective heat losses doubled; respiratory heat losses increased 3-4 fold at 30% and 5-6 fold during 60% exercise; while skin evaporative increased 5-8 fold at 30% and 11-18 fold during exercise at 60% of VO$\sb{\rm 2max}.$ Metabolic rate and MST were stable after 30 minutes of exercise. The energy for climbing (E$\sb{\rm C})$ was equal to the subject's weight x gravity x height climbed. Cavagna and Kaneko's estimate for the energy of walking (E$\sb{\rm W})$ depends on the subject's weight and average forward velocity. For exercise at 30% of VO$\sb{\rm 2max},$ ITC values for radiant, convective and evaporative heat losses, when added to E$\sb{\rm C}$ plus E$\sb{\rm W}$ accounted for all energy produced as determined from IC. At 60% of VO$\sb{\rm 2max},$ ITC values for heat losses, when added to E$\sb{\rm C}$ plus E$\sb{\rm W}$ did not account for all energy produced as determined by IC. The discrepancy may be due to heat storage, or underestimation of skin evaporative heat loss or the energy consumed in walking the horizontal distance. When organized by treadmill speed in W/kg, the energy for climbing and walking was correlated with (R =.92-.98) and linearly related to treadmill grade. At grades higher than 3%, the predicted energy for walking ($\Delta$IC-$\Delta$ITC-E$\sb{\rm C})$ was dependent more on treadmill grade than speed. Energy in W/kg for walking the horizontal distance was correlated with (R =.85-.86) and linear to treadmill grade.
Issue Date:1993
Description:213 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1993.
Other Identifier(s):(UMI)AAI9329138
Date Available in IDEALS:2014-12-17
Date Deposited:1993

This item appears in the following Collection(s)

Item Statistics