Are You Too Old for Weight Training?

EFFECTS OF HUMAN GROWTH HORMONE IN MEN OVER 60 YEARS OLD

IN middle and late adulthood all people experience
a series of progressive alterations in body composition.

The lean body mass shrinks and the mass of
adipose tissue expands. The contraction in lean body
mass reflects atrophic processes in skeletal muscle, liver,
kidney, spleen, skin, and bone.
These structural changes have been considered unavoidable
results of aging.

It has recently been proposed,
however, that reduced availability of growth hormone
in late adulthood may contribute to such
changes.

This proposal is based on two lines of evidence.
First, after about the age of 30, the secretion of
growth hormone by the pituitary gland tends to decline.

Since growth hormone is secreted in pulses,
mostly during the early hours of sleep, it is difficult to
measure the 24-hour secretion of the substance directly.
Growth hormone secretion can be measured indirectly,
however, by measuring the plasma concentration
of insulin-like growth factor I (IGF-I, also known as somatomedin
C), which is produced and released by the
liver and perhaps other tissues in response to growth
hormone.