  An analytical derivation is presented for computing mass-loss rates of
Cepheids by using the method of Castor, Abbott, & Klein (1975) modified to
include a term for momentum input from pulsation and shocks generated in the
atmosphere. Using this derivation, mass-loss rates of Cepheids are determined
as a function of stellar parameters. When applied to a set of known Cepheids,
the calculated mass-loss rates range from 10^{-10} to 10^{-7}M_{Sun}/yr, larger
than if the winds were driven by radiation alone. Infrared excesses based on
the predicted mass-loss rates are compared to observations from optical
interferometry and IRAS, and predictions are made for Spitzer observations. The
mass-loss rates are consistent with the observations, within the uncertainties
of each. The rate of period change of Cepheids is discussed and shown to relate
to mass loss, albeit the dependence is very weak. There is also a correlation
between the large mass-loss rates and the Cepheids with slowest absolute rate
of period change due to evolution through the instability strip. The enhanced
mass loss helps illuminate the issue of infrared excess and the mass
discrepancy found in Cepheids.
