The effect of graded levels of exercise on energy intake and balance in free-living women.
OBJECTIVE
We assessed the effect of graded increases in exercised-induced energy expenditure (EE) on appetite, daily energy intake (EI), total daily EE and body weight in six lean women using a within-subject, repeated measures design.


METHODS
Subjects were each studied three times during 7 day treatments, corresponding to no-exercise (control; Nex; 0 MJ/day), medium exercise level (Mex; approximately 1.9 MJ/day) and high exercise level (Hex; approximately 3.4 MJ/day), with 2 day maintenance beforehand. Subjects self-weighed ad libitum food intake. EE was assessed by continual heart rate monitoring. During waking hours subjects recorded hourly sensations of hunger and appetite.


RESULTS
EE amounted to 9.2, 11.0 and 12.1 MJ/day (F (2, 10)=5.67; P=0.023 (s.e.d.=0.87)) on the Nex, Mex and Hex treatments, respectively. The corresponding values for EI were 8.9, 9.2 and 10.0 MJ/day (F (2, 10)=4.80; P=0.035 (s.e.d.=0.36)). There were very weak treatment effects on hunger. Weight loss was significantly different from zero on the Mex and Hex treatments.


CONCLUSIONS
Markedly increasing EE through exercise produced significant but partial compensations in EI ( approximately 33% of EE due to exercise). Accurate adjustments of El to acute increases in EE are likely to take weeks rather than days.
Stubbs
R J
RJ
The Rowett Research Institute, Bucksburn, Aberdeen, UK. J.Stubbs@rri.sari.ac.uk
Sepp
A
A
Hughes
D A
DA
Johnstone
A M
AM
King
N
N
Horgan
G
G
Blundell
J E
JE
D000328:Adult; D001066:Appetite; D001481:Basal Metabolism; D015992:Body Mass Index; D001835:Body Weight; D004032:Diet; D004435:Eating; D002149:Energy Intake; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006339:Heart Rate; D006801:Humans; D006815:Hunger; D010101:Oxygen Consumption; D017060:Patient Satisfaction; D012044:Regression Analysis; D015431:Weight Loss