title: Endurance training associated with slightly lowered serum estradiol levels decreases mineral density of canine skeleton.
abstract: The effects of long-term running exercise were studied in 20 beagle dogs. A total of 10 dogs ran from the age of 15 weeks to the age of 70 weeks in a progressive program for up to 40 km/day. A total of 10 sister dogs spent the study period in individual cages. When the dogs were 70 weeks old, bone mineral density of the vertebrae, hip, and radius was analyzed by dual-energy x-ray absorptiometry (DEXA; Lunar) and the vertebrae were also assessed by quantitative computed tomography (QCT; Siemens DR 1). Mineral density was lower in the running dogs than in the controls. The difference was greatest in the spine in the QCT analysis. Blood chemistry analyses revealed that the metabolism of the bone was significantly accelerated. The estradiol levels showed the trend to be reduced in the running group. The beneficial effect of exercise on mineral density has been shown in many earlier studies. However, in this study we demonstrate the possibility of adverse effects of long-term exercise on bone tissue. The change was associated with a decrease of serum estradiol level.
authors.affiliation: Department of Anatomy, University of Kuopio, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Puustjärvi
authors.forename: P
authors.initials: P
authors.lastname: Karjalainen
authors.forename: J
authors.initials: J
authors.lastname: Nieminen
authors.forename: J
authors.initials: J
authors.lastname: Arokoski
authors.forename: M
authors.initials: M
authors.lastname: Parviainen
authors.forename: H J
authors.initials: HJ
authors.lastname: Helminen
authors.forename: S
authors.initials: S
authors.lastname: Soimakallio
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D015519:Bone Density / Q000502:physiology*; D002118:Calcium / Q000652:urine; D004285:Dogs; D004958:Estradiol / Q000097:blood*; D005260:Female; D010805:Physical Conditioning, Animal
chemical_list: D004958:Estradiol; D000469:Alkaline Phosphatase; D002118:Calcium