Mini Review Volume 1 Issue 6
1Postgraduate Program in Exercise and Sport Sciences, State University of Rio de Janeiro, Brazil
2Laboratory of Human Motricity Biosciences, Federal University of the State of Rio de Janeiro, Brazil
3Laboratory of Exercise Physiology, Estácio de Sá University, Brazil
Correspondence: Rodrigo Gomes de Souza Vale, Department of Postgraduate Program in Exercise and Sport Sciences, Rio de Janeiro State University, Brazil
Received: July 01, 2017 | Published: August 7, 2017
Citation: Castro JBP, Vale RGS. Insulin-like growth factor i (igf-1) in older adults: a review. MOJ Gerontol Ger. 2017;1(6):175-176. DOI: 10.15406/mojgg.2017.01.00034
Aging can be described as a dynamic and progressive process, including morphological, functional and biochemical changes, as well as psychological modifications. These changes determine the progressive loss of adaptability to the environment, causing a high tendency to vulnerability and a higher incidence of pathological processes.1 Among the inherent alterations in the aging process, it can be highlighted the deficits in balance, mobility, muscular strength, flexibility2,3 changes in body composition, including decreased muscle mass and bone mass4 and endocrine abnormalities, such as the reduction of insulin-like growth factor I (IGF-1) serum levels.5,6
Therefore, the aim of the present study was to review the effects of physical exercises on IGF-1 serum levels in the elderly and the possible mechanisms underlying these responses.
The circulating IGF-1 is mainly produced by the liver in response to increased growth hormone (GH) levels, but it can also be produced in other tissues, including skeletal muscles and bones.7 The IGF-1 provides information about the rate of bone remodeling, related to bone mineral density (BMD)8 and exerts, on the bones, an anabolic effect on the osteoblasts, increasing the cellular proliferation and estimating the synthesis of the bone mineral matrix.9
The IGF-1 generates an anabolic effect on skeletal muscle, related to the preservation of lean body mass.10 Accordingly, the reduction of IGF-1 due to aging may be associated with greater susceptibility to sarcopenia and functional dependence11,12 loss of lean mass, decreased protein synthesis, increased fat mass13 and myostatin in elderly individuals.14 Consequently, higher levels of IGF-1 are associated with improvements in physical fitness15 and lean body mass 10, and reduced risk of heart disease16 and mortality.17
Physical exercises may influence the secretion of hormones in the elderly.18 The hormonal impact of physical exercise can help to verify the effectiveness of training programs to maintain or improve IGF-1 levels and to determine the potential effects of different types of exercise on this hormone. However, the training programs presented methodological differences, such as the type of exercise used, the intensity and the volume of training.19-23
Among the different types of exercises that influenced the IGF-1 serum levels in the elderly, increases of this hormone were found with strength training21,22,24 aerobic training – with aquatic exercises 22 and running25 flexibility training20 dance21,26 and kinesiotherapy.27 The interventions ranged from two to three times per week, during three to six months.
Muscle strength training has shown higher increases in IGF-1 levels in the elderly compared to endurance training.22,25 This may improve functional autonomy28 and quality of life in aging.29
Therefore, due to the benefits of higher levels of IGF-1 in the elderly, it is suggested to extend the knowledge of means that can possibly increase the synthesis and release of this hormone. Thus, future researches should investigate the effects on IGF-1 of different configurations of intensity and volume of training, as well as different types of exercises.
None.
Author declares there is no conflict of interest in publishing the article.
©2017 Castro, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.