circadian clock
They allow for overnight rest stops that are consistent with the drivers' circadian rhythms.
What effect, if any, does circadian rhythm have on pain?
Your circadian rhythms rely on natural light cues.
With jet lag, some people's circadian rhythms are so severely disrupted that they suffer something close to true depression.
SMART Vocabulary: related words and phrases Relating to regular periods of time
afternoons
annual
annum
bi-yearly
biannual
dailiness
daily
daily grind
evenings
fortnightly
hourly
nights
p.c.m.
p.w.
per annum
quadrennial
quadrennially
triennial
triennially
weekly
You can also find related words, phrases, and synonyms in the topics:
Animal & plant biology - general words