  The spectrum of O and B Supergiants is known to be affected by an important
extra line-broadening (usually called macroturbulence) that adds to stellar
rotation. Recent analysis of high resolution spectra has shown that the
interpretation of this line-broadening as a consequence of large-scale
turbulent motions would imply highly super-sonic velocity fields, making this
scenario quite improbable. Stellar oscillations have been proposed as a likely
alternative explanation. We present first encouraging results of an
observational project aimed at investigating the $macroturbulent$ broadening in
O and B Supergiants, and its possible connection with spectroscopic variability
phenomena and stellar oscillations: a) all the studied B Supergiants show line
profile variations, quantified by means of the first (< v >) and third velocity
(< v^3 >) moments of the lines, b) there is a strong correlation between the
peak-to-peak amplitudes of the < v > and < v^3 > variability and the size of
the extra-broadening.
