"Email should not be sent at night, but during the day." When it comes to email etiquette, most people agree that sending late-night emails is unacceptable. Emails, they suggest, should be sent during the day. However, that is founded on the idea of time rather than energy. In actuality, we should be optimizing our energy rather than our time. There are several reasons why sending an email at night is a bad idea. First of all, it's exhausting to do anything for more than eight hours without sleep. Even if you don't feel tired when you first wake up, by noon you will need some rest. Secondly, the human body was not designed to operate on two hours of sleep or less per day. The brain and other organs are deprived of important things they need in order to function properly. For example, research has shown that sleeping less than six hours a night increases your risk of diabetes and heart disease. The best time to send emails is during daytime hours. This allows you to give your recipients time to read their messages and gives them a chance to respond if needed. Sending emails at night uses up your energy without giving others a chance to reply to you. This is why it's best to send emails during the day; so you can avoid any rudeness issues.