I think the phrase "breathing space" is misleading to the point of damage.
How does giving someone "breathing space" sit with making a story "unputdownable"?
"Changing gears" or "Pacing dynamically" is perhaps a better way of phrasing the experience you are looking for.
In movie script writing they refer to each "gear" or mood as a "beat". If you have a movie made entirely of one kind of beat then it just becomes stupefying in some way. Like a constant metronomic pulse... think Transformers 3, yes?
In order to give people a compelling ride you must interpolate beats to make a fascinating rhythm of events. So you have an action beat, then an emotional beat, maybe another action beat, a plot twist beat, an emotional beat, another plot twist and so on and so forth. When authors tend to be bad at this, as far as I can tell, they very much believe that they are giving the audience breathing space. "Emotional Beat" translates in the head of someone who prefers writing action scenes as "Moment of irrelevant whiny introspection". It's also possible to make a reverse error. People who like to write twisty-turny "exposition as action" scenes can really stuff up physical action scenes by making them overlong, one-note, cacophonous descriptions of unemotional laundry-list active descriptions.
Hollywood scriptwriters do not believe in giving the audience breathing space. Bear in mind that screenwriters are authoring works for the most mercurial, perverse, bizarre audience in the world: Hollywood movie producers. If these guys have time to inhale the next thing out of their mouth will likely be that they're not interested in the script.
I am of the school of thought that, like a screenplay, every scene should grab the reader by the scruff of the collar and keep them involved. Rather than just blaring noise into their faces, though, to achieve this, like a great actor, the prose must have its own metre, sometimes soft, sometimes loud, sometimes clever, sometimes stirring, sometimes light, sometimes dark. Like a compelling orator good prose can command a variety of moods but sustain a constant intensity.
Forget "breathing space".
To summarise. You do not need to give a reader breathing space. You need to give them a variety: an action scene with a sense of real stakes in which the reader is emotionally invested; a scene of emotion with a raw and charismatic intensity that seduces and fascinates the reader; a scene of revelation that hammers blows upon the reader's sense that they know where the story is going. If you just repeat any of these things over and over you will end up being tedious; loud and brash; manipulative and cynical; unsure what you are trying to say.
Of course, all of this is easy to say, doing it is the challenge.