How to prevent daytime sleepiness without taking in too much caffeine?

Light and Oxygen: If you feel you have more daytime sleepiness than you should given your work and sleep schedule see your doctor - sleep apnea and restless leg syndrome can disrupt sleep without you knowing it. General tips - try to keep to a regular schedule of light and dark (without that your circadian rhythms will be messed up and you'll have trouble waking up. Also regular exercise, but not too late.