Effect of very low calorie diet on body composition and exercise response in sedentary women.
The effect of very low calorie diet (VLCD) on fat-free mass (FFM) and physiological response to exercise is a topic of current interest. Ten moderately obese women (aged 23-57 years) received VLCD (1695 kJ.day-1) for 6 weeks. FFM, estimated by four conventional techniques, and heart rate (fc), blood lactate (la(b)), mean arterial pressure (MAP), respiratory exchange ratio (R) and rating of perceived exertion (RPE) were measured during a submaximal cycle ergometry test 1 week before, in the 2nd and 6th week, and 1 week after VLCD treatment. Strength and muscular endurance of the quadriceps and hamstrings were tested by isokinetic dynamometry. The 11.5-kg reduction in body mass was approximately 63% fat and 37% FFM. The latter was attributed largely to the loss of water associated with glycogen. Whilst exercise fc increased by 9-14 beats.min-1 (P < 0.01), there were substantial decreases (P < 0.01) in submaximal MAP (1.07-1.73 kPa), la(b) (0.75-1.00 mmol.l-1 and R (0.07-0.09) during VLCD. R and fc returned to normal levels after VLCD. Gross strength decreased (P < 0.01) by 9 and 13% at 1.05 rad.s-1 and 3.14 rad.s-1, respectively. Strength expressed relative to body mass (Nm.kg-1) increased (P < 0.01) at the lower contraction velocity, but there was no change at the faster velocity. Muscular endurance also decreased (P < 0.01) by 62 and 82% for the hamstrings and quadriceps, respectively. We concluded that the strength decrease was a natural adaptation to the reduction in body mass as the ratio of strength to FFM was maintained.(ABSTRACT TRUNCATED AT 250 WORDS)
Eston
R G
RG
Department of Movement Science and Physical Education, University of Liverpool, England.
Shephard
S
S
Kreitzman
S
S
Coxon
A
A
Brodie
D A
DA
Lamb
K L
KL
Baltzopoulos
V
V
D000328:Adult; D001794:Blood Pressure; D001823:Body Composition / Q000502:physiology*; D002149:Energy Intake; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008875:Middle Aged; D009132:Muscles / Q000503:physiopathology; D009765:Obesity / Q000178:diet therapy / Q000503:physiopathology*; D010101:Oxygen Consumption; D010807:Physical Endurance
D007773:Lactates; D019344:Lactic Acid