Afternoon sleepiness can be caused by several factors:

Too little sleep the night before

If you are not getting enough rest overnight, you can find yourself beginning to nod off in the

early afternoon hours. Especially if your job is one where you sit at a desk working at a computer,

the monotony of looking at a computer screen can heighten this drowsiness problem.

Excessive drinking the night before

Drinking a lot of alcohol can bring about sleepiness in the following afternoon. If you can sleep

in, that will sometimes stave off the drowsiness. But if you have to be at your job at the regular

starting time of 8:00 AM, you will find yourself running very low on energy in the afternoon.

Though you might feel energetic in the morning and be able to accomplish your daily duties, there

can be an afternoon 'crash' where you will suddenly feel tired and sleepy.

Eating a heavy lunch or drinking alcohol during lunch

If you eat a very heavy lunch – two or more courses, or if you have an alcoholic drink or two with

lunch you will experience some tiredness during the afternoon.  In fact, this is especially true

because alcohol is a depressant. The physical reaction to alcohol is a sleepy, tired feeling –

drinking at lunch during working hours is not as accepted as it once was during the years of the

'two martini" lunch. Though sometimes beer or two is permitted, always use caution depending upon

the nature of work you will be called upon to complete during the afternoon hours.

If you are recovering from illness

Recovering from a cold or the flu, the illness itself can make you tired before you have finished

your early morning work. If you are taking any cold remedies, one of the side effects can be

drowsiness. Be sure to read the precautions on the label before taking any medications that could

impair your judgment or activity level. In many cases, when recovering from illness, it is better

to return to work in partial days as opposed to full days. Allow your body the time to recover at

its rate, instead of being pushed to do more than you are capable of doing without suffering a

relapse of sickness.