No changes during pregnancy in the net cost of cycling exercise.
OBJECTIVE
To investigate whether work efficiency improves during pregnancy.


METHODS
Longitudinal; energy expenditure measurements (ventilated hood system) before the onset of pregnancy and in weeks 13, 24 and 35 of gestation.


METHODS
Healthy Dutch women (n = 26), recruited with advertisements in local newspapers and posters displayed in public buildings.


METHODS
Resting metabolic rate (RMR); metabolic rate during cycling at workloads of 30, 45, 60 and 75 W (CMRgross); post-cycling metabolic rate (PCMRgross); net energy costs of cycling (CMRnet = CMRgross - RMR); net recovery costs after cycling exercise (PCMRnet = PCMRgross - RMR).


RESULTS
RMR, CMRgross and PCMRgross increased during pregnancy; under all conditions, metabolic rates were 0.9 kJ/min higher at 35 weeks gestation than before pregnancy (P < 0.05). CMRnet and PCMRnet showed no significant change during gestation.


CONCLUSIONS
Changes in metabolic rate during cycling exercise suggest that pregnancy does not induce an improvement of work efficiency.
Spaaij
C J
CJ
Department of Human Nutrition, Wageningen Agricultural University, The Netherlands.
van Raaij
J M
JM
de Groot
L C
LC
van der Heijden
L J
LJ
Boekholt
H A
HA
Hautvast
J G
JG
D000328:Adult; D004734:Energy Metabolism; D005080:Exercise Test; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D005082:Physical Exertion / Q000502:physiology*; D011247:Pregnancy / Q000378:metabolism*; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012146:Rest