Effects of exercise training and its cessation on components of the insulin resistance syndrome in obese children

Abstract

OBJECTIVE: To determine the effect of exercise training (ET) on components of the insulin resistance syndrome (IRS) in obese children. DESIGN: Randomized, modi®ed cross-over study, with subjects assigned to one 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 fat (%fat) 27 ± 61%). MEASUREMENTS: Plasma lipid and lipoprotein concentrations, plasma insulin and glucose concentrations; %fat; submaximal heart rate (HR) as an index of ®tness. EXERCISE TRAINING: ET was offered 5 daweek 40 minad. For the 73 children who completed 4 months of ET, the mean attendance was 80% (that is, 4 daweek) and the average HR during ET was 157 bpm. RESULTS: Signi®cant (P`0.05) group x time interactions were found for plasma triglyceride (TG) and insulin concentrations and %fat. The average change for both groups, from just before ET to just after the 4 month ET was À0.24 mmol Á l À1 for TG, À25.4 pmol Á l À1 for insulin and À1.6 units for %fat. When Group 1 ceased ET, over the following 4 month period the average change for insulin was 26.6 pmol Á l À1 and for %fat 1.3 units. CONCLUSION: Some components (plasma TG, insulin, %fat) of the IRS are improved as a result of 4 months of ET in obese children. However, the bene®ts of ET are lost when obese children become less active.

Efficacy of exercise for treating overweight in children and adolescents: a systematic review

“…Of 45 potentially relevant papers considered, we excluded 32 for the following reasons: eight were conducted in mixed weight cohorts, [31][32][33][34][35][36][37] four were specifically conducted in normal weight cohorts, [38][39][40][41] six studies compared overweight subjects with normal weight control subjects, [42][43][44][45][46][47] five studies were nonrandomized trials [48][49][50][51][52] and nine studies [53][54][55][56][57][58][59][60][61] published data which were previously published, in three studies already included in this review. 51,62,63 Treatment/intervention All studies were of supervised exercise. One study prescribed exercise in a clinical laboratory setting, 63 whereas the remainder used various outdoor/indoor settings.…”

“…One study compared the effects of two different exercise plus behavioral treatments with that of a control group which received the behavioral treatment alone (three arm study) providing two datum points, 64 and was therefore included as two separate studies. Among these 14 studies, two compared the effects of aerobic exercise with untreated controls, 29,62 one study compared the effect of a device which permitted television viewing contingent to exercise (TV cycling) with that of a control group which received a similar device but differed in that television viewing was not contingent to exercise, 65 one investigated the effects of 'extra gymnastics' sessions/weeks reported to entailed 45 min of intense physical activity performed in a small group setting compared to untreated controls, 66 whereas the remaining nine studies compared the effects of various dietary/behavioral treatments with/without aerobic exercise 30,[67][68][69][70][71] or combined aerobic and weighttraining exercise. 63,64,72 The mean (7s.d.)…”

“…Only two studies investigated long-term treatment effects beyond the intervention phase, one of which reported follow-up data at 26 and 52 weeks, 67 and another at 52 weeks. 63 Eight studies were conducted in the US, 29,30,62,65,67,68,70,71 one in Australia, 69 one in Austria, 72 one in Canada, 64 one in Sweden 66 and one in Hong Kong. 63 Cohorts Of 14 studies, one was in boys only, 66 one was in girls only, 67 11 were in boys and girls, 29,30,[62][63][64][65]68,[70][71][72] whereas gender characteristics were not reported in another.…”

“…63 Eight studies were conducted in the US, 29,30,62,65,67,68,70,71 one in Australia, 69 one in Austria, 72 one in Canada, 64 one in Sweden 66 and one in Hong Kong. 63 Cohorts Of 14 studies, one was in boys only, 66 one was in girls only, 67 11 were in boys and girls, 29,30,[62][63][64][65]68,[70][71][72] whereas gender characteristics were not reported in another. 69 In total, the 14 studies pooled yielded a sample of 481 boys and girls, and the mean age reported in nine studies was 10.971.5 years, while age ranges of 13-16 years was reported in one study, 30 of 8-12 years in one study, 67 and of 12-15 years in two Efficacy of exercise for treating overweight in youth E Atlantis et al studies (two treatments from one study), 64 while another did not report age (mean or range).…”

“…64 Randomization protocols were clearly described in only four studies. 62,[65][66][67] The proportion of subjects recruited which completed each respective study, defined as the number of subjects with pre-and post-test data, divided by the number of subjects recruited, ranged between 50 and 100% (median 96%). Only six studies analyzed post-test data on all subjects who entered as study participants, 29,63,[68][69][70]72 whereas eight studies analyzed post-test data in study completers only.…”