Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 51, Issue 1 B38-B42, Copyright © 1996 by The Gerontological Society of America
The effect of exercise training on cold tolerance in adult and old C57BL/6J mice
VI Schaefer, MI Talan and O Shechtman
Laboratory of Behavioral Sciences, National Institute on Aging, Baltimore, USA.
In order to ascertain the effect of aging on cross-adaptation between
exercise training and cold tolerance, we studied cold tolerance in adult
and old C57BL/6J male mice before and after 6 weeks of an exercise regimen
of moderate intensity. There were two age groups of 32 mice each, including
12-month-old (adult) and 24-month-old (aged) mice equally divided into
control and exercise groups. The exercise consisted of daily runs on a
treadmill (1 hr/day, 5 days/week) for 6 weeks, while the control mice spent
the same time on a stationary treadmill. All mice were subjected to a cold
stress test (3-hr partial restraint at 6 degrees C) prior to and following
the designated regimen. The results revealed a statistically significant
interaction between age and exercise training. In adult mice, exercise
resulted in a reduction of cold-induced heat production and weakening of
cold tolerance, while in aged mice, the opposite effect was observed; i.e.,
an increase in cold-induced heat production accompanied by greater cold
tolerance. However, only the attenuating effect on cold tolerance of adults
was statistically significant. The results of our experiments do not
support the existence of cross-adaptation between exercise training and
cold tolerance. They indicate, however, that exercise training affects the
cold tolerance in adult and old mice through different physiological
mechanisms.
