score:8
It is an experience, like any other, so you have to face it and recognize it clearly as it is. In our tradition we describe the experience of catching up the fatigue in one's awareness and reminding oneself "tired, tired"; if one's mindfulness is sharp, it will either disappear completely or, if the body needs sleep, one will fall asleep.
As the Mahasi Sayadaw describes this process:
Make a mental note of drowsy, when drowsy, and sleepy, when sleepy. After you have gained sufficient concentration in contemplating you will be able to overcome drowsiness and sleepiness and feel refreshed as a result. Take up again the usual contemplation of the basic object. Suppose you are unable to overcome a drowsy feeling, you must then continue to contemplate until you fall asleep.
Also, the commentary to the Satipatthana sutta has a number of ancillary techniques for overcoming sloth and torpor:
http://www.accesstoinsight.org/lib/authors/soma/wayof.html#sloth
Upvote:3
Some things that have worked for me-- and may be entirely personal:
Sometimes these practices have caused my torpor to suddenly "flip" into very bright concentration. Sometimes torpor is actually concealing some unacknowledged agitation, and when that agitation is known, the sluggishness vanishes.
However, that's less likely if it's genuine physical exhaustion, or sluggishness caused by digesting a meal. "Sometimes a cigar is just a cigar" :)