go downhill
To worsen or degenerate.
I usually run fast enough, but my speed goes downhill when I don't sleep enough.
ADJ.
all, all, fast, light, long
VERB + DOWNHILL
found, go, goes, going, gone, kept, leads, pushed
DOWNHILL + NOUN
afternoon, course, sections, shrewsbury, uphill, way
PREP.
after, after, from, in, into, on, with, with
ADV.
definitely, nearly, only