Yogi: I couldn’t sleep all night because I was coughing, but the mind was still fresh the next day.

Sayadaw: When not sleeping becomes a problem, it means that there’s a lot of defilement thinking. If you’re not thinking, and you’re trying to be aware the whole night, not sleeping isn’t a problem.

Resistance and defilement thinking make the mind tired. If you’re aware and can maintain your samadhi the whole night, not sleeping is not a problem.

That’s why some yogis practice meditating the whole night long (to prevent defilement thinking during sleep). Now you are already doing that practice.