documentclass{article}

usepackage{mathabx}

begin{document}

$upuparrows$ -  $downdownarrows$ - $updownarrows$ - $downuparrows$

end{document}

documentclass{article}

usepackage{amsmath,amssymb}

newcommand{updownarrows}{mathbinuparrowhspace{-.5em}downarrow}
newcommand{downuparrows}{mathbindownarrowhspace{-.5em}uparrow}

begin{document}

$upuparrows$ -  $downdownarrows$ - $updownarrows$ - $downuparrows$


end{document}

documentclass{article}

usepackage{amsmath,amssymb}

newcommand{updownarrows}{mathbinuparrowhspace{-.3em}downarrow}
newcommand{downuparrows}{mathbindownarrowhspace{-.3em}uparrow}
renewcommand{upuparrows}{mathbinuparrowhspace{-.3em}uparrow}
renewcommand{downdownarrows}{mathbindownarrowhspace{-.3em}downarrow}

begin{document}

$upuparrows$ -  $downdownarrows$ - $updownarrows$ - $downuparrows$

end{document}

documentclass{article}

usepackage{amsmath,amssymb}

newcommand{updownarrows}{uparrowmathrel{mspace{-1mu}}downarrow}
newcommand{downuparrows}{downarrowmathrel{mspace{-1mu}}uparrow}
renewcommand{upuparrows}{uparrowuparrow}
renewcommand{downdownarrows}{downarrowdownarrow}

begin{document}

$upuparrows$ -  $downdownarrows$ - $updownarrows$ - $downuparrows$

end{document}