title: Igf-I and fgf-2 responses to wingate anaerobic test in older men.
abstract: insulin-like growth factor-I (IGF-I) and fibroblast growth factor-2 (FGF-2), play a role in aging associated muscle loss. The effect of fitness level on IGF-I and FGF-2 responses to all-out anaerobic exercise in older men was studied. Twenty four healthy older males: 12 higher fit (58 ± 1y) and 12 lower fit (59 ± 1y) underwent the Wingate anaerobic test. Serum levels of IGF-I and FGF-2 were measured before, immediately after exercise, and 50 min into recovery. Immediately post exercise, the average peak power output and serum lactate were higher (p < 0.05) in the higher fit (446.0 ± 14. 9 kgm·min(-1) for mean (± SD) peak power and 12.6 ± 1.1 mml·l(-1) for lactate) compared with the lower fit individuals (284.0 ± 6.5 kgm·min(-1) and 8.5 ± 0.7 mml·l(-1), respectively). Pre-exercise IGF-I was lower and FGF-2 was higher in the higher fit (335.0 ± 54.0 ng·ml(-1) and 1.6 ± 0.1 ng·ml(-1), respectively) compared with lower fit individuals (402.0 ± 50.0 ng·ml(-1) and 1.4 ± 0.2 ng·ml(-1), respectively). Following the anaerobic exercise, in both groups, FGF-2 decreased dramatically (p < 0.05); in the higher fit individuals FGF-2 level was 0.4 ± 0.1 pg·ml(-1) compared to 0.1 ± 0.02 pg·ml(-1) in the lower fit individuals. In contrast to FGF-2, IGF-I increased transiently to levels of 405.0 ± 62.0 ng·ml(-1) in the higher fit individuals and to levels of 436 ± 57.0 ng·ml(-1) in the lower fit individuals. However, the IGF-I elevation was significant (p < 0. 05) only in the higher fit individuals. In conclusion, the present study demonstrates that during aging, fitness level can alter circulating levels of IGF-I and FGF-2. Furthermore, fitness level can affect the response of both mediators to all-out anaerobic exercise. Key pointsThe present study suggests that during aging, fitness level can alter circulating levels of IGF-I and FGF-2.Furthermore, fitness level can affect the response of both mediators to all-out anaerobic exercise.Anaerobic muscle activity is represented in many daily life activities of elderly individuals.This may have clinical implications during aging, where the declined activity of growth factors is a major determinant of the loss of muscle strength and function.
authors.affiliation: Sports Medicine & Rehabilitation Division, Zinman College of Physical Education and Sport Sciences , Wingate, Israel.
authors.forename: Ruthie
authors.initials: R
authors.lastname: Amir
authors.forename: David
authors.initials: D
authors.lastname: Ben-Sira
authors.forename: Moran
authors.initials: M
authors.lastname: Sagiv
keywords: Anaerobic exercise; aging; angiogenesis; growth factors; hypertrophy