Ma. Ferguson et al., Effects of exercise training and its cessation on components of the insulin resistance syndrome in obese children, INT J OBES, 23(8), 1999, pp. 889-895
OBJECTIVE: To determine the effect of exercise training (ET) on components
of the insulin resistance syndrome (IRS) in obese children.
DESIGN: Randomized, modified cross-over study, with subjects assigned to on
e of two conditions: (1) 4 months of ET followed by 4 months of no-ET; or (
2) 4 months of no-ET:followed by 4 months of ET. Measurements were made at
three time points: 0, 4 and 8 months.
SUBJECTS: 79 obese, but otherwise healthy children (age: 7-11 y, percent fa
t (%fat) 27-61%).
MEASUREMENTS: Plasma lipid and lipoprotein concentrations, plasma insulin a
nd glucose concentrations; %fat; submaximal heart rate (HR) as an index of
fitness.
EXERCISE TRAINING: ET was offered 5 d/week 40 min/d. For the 73 children wh
o completed 4 months of ET, the mean attendance was 80% (that is, 4d/week)
and the average HR during ET was 157 bpm.
RESULTS: Significant (P < 0.05) group x time interactions were found for pl
asma triglyceride (TG) and insulin concentrations and %fat. The average cha
nge for both groups, from just before ET to just after the 4 month ET was -
0.24 mmol.l(-1) for TG, -25.4 pmol.l(-1) for insulin and -1.6 units for %fa
t. When Group 1 ceased ET, over the following 4 month period the average ch
ange for insulin was +26.6 pmol.l(-1) and for %fat +1.3 units.
CONCLUSION: Some components (plasma TG, insulin, %fat) of the IRS are impro
ved as a result of 4 months of ET in obese children. However, the benefits
of ET are lost when obese children become less active.