Adequate sleep at night or an afternoon nap itself is a priceless luxury for those in the fast lane. In many cases a small duration 'shut eye' or the so-called Power Nap can be a huge refresher. Everyone has different indications when the body cries out for a pause and we often ignore them. These symptoms range between moodiness/drooping eyes/ lethargy/ difficulty in decision making or communicating to name just a few.
It works best if one can comfortably lie down in a quiet place. Generally a maximum of 30 minutes of sleep works best to recharge both body and mind. Longer can take a person into deeper sleep stages which can lead to sleeplessness at night. Solution: set the alarm even for a 20-minute nap.
This does not take away the importance of adequate sleep at night. Some experts opine that if a person gets adequate night sleep then there is no reason to feel tired during the day. Others recommend the power nap as a simple mid day relaxation technique.
Either way there is no reason for not grabbing 40 winks provided work efficiency remains high and its not an excuse to shirk work. Listen and understand your body and choose what works best for you.