  We calculate the low-energy limit of heavy quark current correlators within
an expansion in the inverse heavy quark mass. The induced low-energy currents
built from the gluon fields corresponding to the initial heavy quark currents
are obtained from an effective action for gauge fields in the one-loop
approximation at the leading order of the 1/m expansion. Explicit formulae for
the low-energy spectra of electromagnetic and tensor heavy quark current
correlators are given. Consequences of the appearance of a nonvanishing
spectral density below the two-particle threshold for high precision
phenomenology of heavy quarks are discussed quantitatively.
