Caffeine can decrease memory performance, unlike the nap, which actually boost your memory, cognitive skills and energy as well. Power naps can also lift the mood and make you more productive. So, all you have to do is take a nap in the morning or after lunch, but avoid napping in the afternoon – because of the way our body works, it’s more likely that period of the day to fall in deep sleep (the one at night). It is also important to keep the naps short, 20 minutes or so.