Your performing cardiovascular exercise
you don't work at too high an intensity level
your heart is strengthened<span />
Probably because copper contracts and expands when it is cold or hot, respectively. he added slack to the line so when it gets cold the line does not contract too much and break.
The reason for the gender differences in energy metabolism is not known; however, it may relate to sex steroids, differences in insulin resistance, or metabolic effects of other hormones such as leptin.