The short answer
Gardens and tea rooms. Le Jardin Secret is a calm, restored riad garden in the heart of the medina; the Menara Gardens have olive groves and open space around a big basin; Jardin Majorelle is shaded and compact if you go at opening time. A riad roof terrace or a quiet tea room does the same in minutes.
In more detail
Le Jardin Secret is the closest escape to the souks. It is a restored riad garden with an Islamic-style courtyard, an exotic garden and running water, a welcome breather between busy lanes, with a tower to climb for rooftop views.
The Menara Gardens, Almohad-era olive groves around a huge reflecting basin, give children room to stretch their legs, and families picnic under the trees with the Atlas behind on clear days. Jardin Majorelle is compact and shaded, but popular, so go early to beat both heat and queues.
Inside the medina, a tea room is the quick fix. Riad Yima's tea room, down an alley behind the spice square, is a gallery and salon de thé. Dar Daoud Tea Lounge sits in a Mouassine riad that was once a painter's studio. The tea salon of the Moroccan Culinary Arts Museum, next to the Bahia Palace, is in a restored palace.
The simplest break is your riad. Its courtyard faces inwards, with no street noise, so a midday rest there, or at a pool, resets everyone for an evening at the square.