sleep cycle
... that as you progress through your 90-minute sleep cycle, your brainwaves change and your body secretes different hormones?
... that as you progress through your 90-minute <b id="mwBSo"><a href="./Sleep_cycle" id="mwBSs" rel="mw:WikiLink" title="Sleep cycle">sleep cycle</a></b>, your <a href="./Neural_oscillation" id="mwBSw" rel="mw:WikiLink" title="Neural oscillation">brainwaves</a> change and your body secretes different <a href="./Hormone" id="mwBS0" rel="mw:WikiLink" title="Hormone">hormones</a>?