Do your prefer to push yourself and work through drowsiness or have a good rest and start refreshed?
for me it entirely depends on the circumstances.
i am the kind that works best under pressure, so if i happen to have a deadline on a project, best believe i will exhaust all the last energy i have in me to finish it.
I tend to have a relaxed mindset when its the opposite and rest at every slightest need . When i feel that i am not being as productive as i should be, i take power naps, i believe in these things (power naps), as 30-45 mins of good rest to recharge is better than 2 hours of being ineffective.