  Let $\H$ denote the discrete Heisenberg group, equipped with a word metric
$d_W$ associated to some finite symmetric generating set. We show that if
$(X,\|\cdot\|)$ is a $p$-convex Banach space then for any Lipschitz function
$f:\H\to X$ there exist $x,y\in \H$ with $d_W(x,y)$ arbitrarily large and
\begin{equation}\label{eq:comp abs} \frac{\|f(x)-f(y)\|}{d_W(x,y)}\lesssim
\left(\frac{\log\log d_W(x,y)}{\log d_W(x,y)}\right)^{1/p}. \end{equation}
  We also show that any embedding into $X$ of a ball of radius $R\ge 4$ in $\H$
incurs bi-Lipschitz distortion that grows at least as a constant multiple of
\begin{equation}\label{eq:dist abs} \left(\frac{\log R}{\log\log
R}\right)^{1/p}. \end{equation}
  Both~\eqref{eq:comp abs} and~\eqref{eq:dist abs} are sharp up to the iterated
logarithm terms. When $X$ is Hilbert space we obtain a representation-theoretic
proof yielding bounds corresponding to~\eqref{eq:comp abs} and~\eqref{eq:dist
abs} which are sharp up to a universal constant.
