Effect of physical training on age-related reduction of GH secretion during exercise in normally cycling women.
OBJECTIVE
To evaluate whether prolonged physical activity (25 km/week running for 8 years) modifies GH decline.


METHODS
The GH response to maximal exercise on bicycle-ergometer was tested in younger (26-30 years) and older (42-46 years) healthy women. Each age group included 2 subgroups of 10 sedentary and 10 runners, which were compared. The workload was increased at 3 min intervals from time 0 until exhaustion. Subjects with a low maximal capacity (as established in a preliminary test) pedalled for 3-4 min against no workload at the beginning of the test, so that exercises lasted about 15 min in all individuals.


RESULTS
At exhaustion, heart rate and systolic pressure were significantly higher in sedentary than in trained subjects, whereas V(O(2)max), blood glucose and plasma lactate levels were similar in all groups. Exercise induced similar GH responses in younger sedentary and exercise-trained subjects and in older exercise-trained subjects, with mean peak levels 7.5 times higher than baseline. In contrast, in older sedentary women peak GH level was only 4.4 times higher than baseline and was significantly lower than in the other groups.


CONCLUSIONS
These data suggest that in women prolonged physical training exerts protective effects against age-dependent decline in GH secretion.
Coiro
Vittorio
V
Department of Internal Medicine and Biomedical Sciences, Via A. Gramsci 14, 43100 Parma, Italy. vittorio.coiro@unipr.it
Volpi
Riccardo
R
Gramellini
Dandolo
D
Maffei
Maria Ludovica
ML
Volta
Elio
E
Melani
Andrea
A
Chiodera
Paolo
P
D000328:Adult; D000375:Aging / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D019382:Human Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D047648:Perimenopause; D057185:Sedentary Behavior
D019382:Human Growth Hormone