K. Hakkinen et A. Pakarinen, MUSCLE STRENGTH AND SERUM TESTOSTERONE, CORTISOL AND SHBG CONCENTRATIONS IN MIDDLE-AGED AND ELDERLY MEN AND WOMEN, Acta Physiologica Scandinavica, 148(2), 1993, pp. 199-207
Forty healthy males (M) and females (F) divided into two different age
groups i.e. M50 years (range 44-57; n = 9), F50 years (range 43-54; n
= 9), M70 years (range 64-73; n = 11) and F70 years (range 63-73; n =
11) volunteered as subjects for examination of muscle cross-sectional
area (CSA) and maximal voluntary isometric force production character
istics of the leg extensor muscles and serum androgen and sex hormone
binding globulin (SHBG) concentrations. The CSA in the male groups was
greatly larger (P < 0.01) than in the female groups and both elderly
groups demonstrated slightly (n.s.) smaller values in the CSA than the
two middle-aged groups. Maximal force of 2854 +/- 452 N in M50 was gr
eater (P < 0.05) than that of 2627 +/- 752 N recorded for F50 as well
as the force of 2787 +/- 843 in M70 was greater (P < 0.001) than that
of 1849 +/- 295 recorded for F70. The force between F50 and F70 differ
ed significantly (P < 0.05) from each other. The maximal rate of force
production in M50 was greater (P < 0.01) than in F50 as well as in M7
0 greater (P < 0.001) than in F70. Both middle-aged groups demonstrate
d greater (P < 0.05) values than the respective elderly groups of the
same sex. The individual values in the CSA correlated with the values
in maximal force both in the middle-aged subjects (r = 0.66; P < 0.01)
and in the elderly subjects (r = 0.69; P < 0.01). The mean concentrat
ion of serum testosterone in M50 was slightly (n.s.) greater than in M
70 and in F50 significantly (P < 0.05) greater than in F70. Serum SHBG
levels were lower in the males (P < 0.01) than in the females and ser
um testosterone/SHBG ratio in M70 and in F70 were lower (P < 0.05) tha
n in M50 and in F50, respectively. In the females significant positive
correlations were observed between the individual values in serum tes
tosterone concentration and the values both in the CSA (r = 0.46; P <
0.05) and in maximal force (r = 0.62; P < 0.01) as well as between ser
um testosterone/SHBG ratio and both the CSA (r = 0.55; P < 0.05) and m
aximal force (r = 0.68; P < 0.01). The present results imply that the
decreasing basal level of blood testosterone over the years in aging p
eople, especially in females, may lead to decreasing anabolic effects
on muscles thus having an association with age-related declines in the
maximal voluntary neuromuscular performance capacity in aging people.