Influence of acute and chronic exercise on insulin-like growth factor-I inhealthy active elderly men and women

We examined the influence of physical activity (PA) and acute resistance ex ercise on insulin-like growth factor I (IGF-I) in 39 healthy, independent, community-dwelling elderly volunteers (14 men and 25 women) aged from 66 to 84. In a longitudinal non-interventional study, we compared the fluctuatio ns in IGF-I levels and changes in habitual PA over a 6-month period. PA was evaluated by a questionnaire QAPSE (Questionnaire d'Activite Physique Sain t-Etienne), and expressed by two activity indices: mean habitual daily ener gy expenditure (MHDEE), and daily energy expenditure corresponding to leisu re time sports activities (sports activity index). In an experimental desig n we compared IGF-I levels before, at 1 and 15 minutes after short quadrice ps muscle exertion (10 consecutive repetitions) carried out with optimal mu scle power development. Changes in IGF-I levels over a 6-month period were positively related to changes in MHDEE (r=0.41; p<0.01), and sports activit y (r=0.40; p<0.02). When analyzed by gender, these correlations were still statistically significant in women (r=0.39; p=0.05 and r=0.41; p<0.05), but not in men (r=0.36; p=0.21 and r=0.20; p=0.50). No changes (p=0.17) were o bserved in serum IGF-I concentrations after the acute exercise protocol. Th ese findings indicate that IGF-I levels are positively related to fluctuati ons in habitual PA, at least in women. Further research is needed to establ ish the best intensity and duration of exercise training to induce these ch anges. (Aging Clin. Exp. Res. 11: 373-379, 1999) (C)1999, Editrice Kurtis.