The pairs of activities that can best help a dancer develop better stage performance would most likely be muscle-strengthening and balance/stretching.
When you think about it - dancers obviously need muscles to a certain extent in order to be able to move in a specific way but they also need good balance and the ability to stretch. All of these things play an important role in dancing :)
Sweat glands release sweat when your body is heated up, which cools your sin as it evaporates. This lowers your body heat like when you have a fever, are under stress or when exercising.