|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 204, Issue 3 599-605, Copyright © 2001 by Company of Biologists
JOURNAL ARTICLES |
E Edwards and T Gleeson
Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder, CO 80309-0334, USA. bakerej@ucsu.colorado.edu
Previous research has shown that the energetic expense per unit distance traveled for one bout of short-duration activity is much greater than the energetic expense associated with long-duration activity. However, animals are often seen moving intermittently, with these behaviors characterized by brief bouts of activity interspersed with brief pauses. We hypothesized that, when multiple bouts of brief activity are performed intermittently, the energetic cost per unit distance is less than when only one short bout is performed. Mice were run 1, 2, 3, 5, 9 or 13 times for 15 s at their maximal speed within a 375 s period while enclosed in an open-flow respirometry system on a treadmill. The mice were also run continuously for 375 s. Following the last sprint and the continuous run, the mice remained in the respirometry chamber until their vdot (O2) reached resting levels. Excess exercise oxygen consumption (EEOC), the excess volume of oxygen consumed during the exercise period, increased from 0.03+/-0.01 to 0.40+/-0.02 ml O(2 )g(-)(1) (mean +/- s.e.m., N=9) with activity frequency. However, the excess post-exercise oxygen consumption (EPOC), or volume of oxygen consumed during the recovery period, was independent of activity frequency (range 0.91-1.16 ml O(2 )g(-)(1)) and accounted for more than 80 % of the total metabolic cost when activity was performed intermittently. Lactate concentration was measured at rest, immediately after running and immediately after recovering from running 1, 5 and 13 times within the 375 s period. After running, [lactate] was significantly higher than resting values, but following recovery, [lactate] had reached resting values. The net cost of activity, C(act), calculated by summing EEOC and EPOC and then dividing by the distance run, decreased significantly from 132+/-38 to 6+/-1 ml O(2 )g(-)(1 )km(-)(1) as activity frequency increased. When these values for C(act) were compared with the cost of running continuously for the same amount of time, the values were identical. Therefore, we conclude that animals can minimize energetic expenditure by performing brief behaviors more frequently, just as they can minimize these costs if they increase the duration of continuous behaviors.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  S. Ward, U. Moller, J. M. V. Rayner, D. M. Jackson, W. Nachtigall, and J. R. Speakman Metabolic power of European starlings Sturnus vulgaris during flight in a wind tunnel, estimated from heat transfer modelling, doubly labelled water and mask respirometry J. Exp. Biol., November 15, 2004; 207(24): 4291 - 4298. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Girard, M. W. McAleer, J. S. Rhodes, and T. Garland Jr. Selection for high voluntary wheel-running increases speed and intermittency in house mice (Mus domesticus) J. Exp. Biol., March 14, 2002; 204(24): 4311 - 4320. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. T. Gleeson and T. V. Hancock Modeling the Metabolic Energetics of Brief and Intermittent Locomotion in Lizards and Rodents Integr. Comp. Biol., April 1, 2001; 41(2): 211 - 218. [Abstract] [Full Text] [PDF]
|
|
