Percentage contribution of increased heart rate to increased oxygen transport during activity in Pseudemys scripta, Terrapene ornata and other reptiles

Abstract

A new formula which correctly expresses the percentage contribution of increased heart rate to increased oxygen transport during activity is presented. 2. The percentage contribution is reported for the turtles Pseudemys scripta and Terrupene ornata at body temperatures of 1@-4O"C. 3. Corrected values for this parameter in reptiles studied at 30°C by other authors are also presented.

Aspects of cardiovascular oxygen transport in vertebrates

“…This is contrary to the conclusions of Carey (1979) who calculated (based on the equations of Gatten, 1974) a decline in the percentage contribution of heart rate during activity in A· boreas from 5% at s 0 c to 1.7% at 3ooc. Although she did not measure blood flow rates or A-V differences, she concluded that stroke volume and/or A-V difference must contribute the most to increased V02 during activity.…”

Aspects of cardiovascular oxygen transport in vertebrates

“…This is contrary to the conclusions of Carey (1979) who calculated (based on the equations of Gatten, 1974) a decline in the percentage contribution of heart rate during activity in A· boreas from 5% at s 0 c to 1.7% at 3ooc. Although she did not measure blood flow rates or A-V differences, she concluded that stroke volume and/or A-V difference must contribute the most to increased V02 during activity.…”

Aspects of cardiovascular oxygen transport in vertebrates

“…Since temperature significantly increased heart rate during rest and activity, it would appear that increased cardiac output in amphibians is primarily augmented by heart rate and not stroke volume. This is contrary to the conclusions of Carey (1979) who calculated (based on the equations of Gatten, 1974) a decline in the percentage contribution of heart rate during activity in A• boreas from 5% at s 0 c to 1.7% at 3ooc. Although she did not measure blood flow rates or A-V differences, she concluded that stroke volume and/or A-V difference must contribute the most to increased V02 during activity.…”

Constraints of bioenergetics on the ecology and distribution of vertebrate ectotherms

“…The results of this research should make it possible to use cardiac rate as an index of energy expenditure in these turtles. While the correlation between metabolic rate and heart rate is not absolute ( Gatten 1974 ), it appears to be sufficient for the purposes of this study. This, combined with behavioral time-budget analysis, will allow the calculation of energy budgets for this species.…”

Aspects of cardiovascular oxygen transport in vertebrates

“…This is contrary to the conclusions of Carey (1979) who calculated (based on the equations of Gatten, 1974) a decline in the percentage contribution of heart rate during activity in A· boreas from 5% at s 0 c to 1.7% at 3ooc. Although she did not measure blood flow rates or A-V differences, she concluded that stroke volume and/or A-V difference must contribute the most to increased V02 during activity.…”

Aspects of cardiovascular oxygen transport in vertebrates

“…Since temperature significantly increased heart rate during rest and activity, it would appear that increased cardiac output in amphibians is primarily augmented by heart rate and not stroke volume. This is contrary to the conclusions of Carey (1979) who calculated (based on the equations of Gatten, 1974) a decline in the percentage contribution of heart rate during activity in A• boreas from 5% at s 0 c to 1.7% at 3ooc. Although she did not measure blood flow rates or A-V differences, she concluded that stroke volume and/or A-V difference must contribute the most to increased V02 during activity.…”

Constraints of bioenergetics on the ecology and distribution of vertebrate ectotherms

“…The results of this research should make it possible to use cardiac rate as an index of energy expenditure in these turtles. While the correlation between metabolic rate and heart rate is not absolute ( Gatten 1974 ), it appears to be sufficient for the purposes of this study. This, combined with behavioral time-budget analysis, will allow the calculation of energy budgets for this species.…”

Aspects of cardiovascular oxygen transport in vertebrates

“…This is contrary to the conclusions of Carey (1979) who calculated (based on the equations of Gatten, 1974) a decline in the percentage contribution of heart rate during activity in A· boreas from 5% at s 0 c to 1.7% at 3ooc. Although she did not measure blood flow rates or A-V differences, she concluded that stroke volume and/or A-V difference must contribute the most to increased V02 during activity.…”

Aspects of cardiovascular oxygen transport in vertebrates

“…Since temperature significantly increased heart rate during rest and activity, it would appear that increased cardiac output in amphibians is primarily augmented by heart rate and not stroke volume. This is contrary to the conclusions of Carey (1979) who calculated (based on the equations of Gatten, 1974) a decline in the percentage contribution of heart rate during activity in A• boreas from 5% at s 0 c to 1.7% at 3ooc. Although she did not measure blood flow rates or A-V differences, she concluded that stroke volume and/or A-V difference must contribute the most to increased V02 during activity.…”

Constraints of bioenergetics on the ecology and distribution of vertebrate ectotherms

“…The results of this research should make it possible to use cardiac rate as an index of energy expenditure in these turtles. While the correlation between metabolic rate and heart rate is not absolute ( Gatten 1974 ), it appears to be sufficient for the purposes of this study. This, combined with behavioral time-budget analysis, will allow the calculation of energy budgets for this species.…”