It is critical to pace oneself appropriately during a workout. If you workout too quickly, you risk having a heart attack before you've worked the muscles sufficiently. Furthermore, you may tend to become sloppy and begin flinging the weights around instead of performing each movement correctly.
However, training too slowly is also detrimental. For example, if you wait 5 minutes between sets, your heart rate will slow, you will lose your pump, your muscles will become cold, and your level of intensity will be zero.
Rest intervals between sets should be kept to a minute or less. After a weight-training exercise, you recover 72 percent of your strength in the first minute. By 3 minutes, you have recovered everything; you will recover without extended rest.
However, remember that this training aims to stimulate and fatigue as much muscle fiber as possible. This occurs only when the body is forced to recruit additional muscle fiber to replace what is already depleted.
So you don't want to give your muscles too much time to recover between sets—just enough to allow you to continue your workout and force your body to recruit more and more muscle tissue.
One more thing to think about: Physiologists have long recognized the connection between maximal muscle strength and muscular endurance.
The more powerful you are, the more frequently you can lift a submaximal weight. The more you push yourself to improve muscular endurance (rather than cardiovascular endurance), the stronger you will become.
Maintaining a consistent tempo in your exercise results in a gain in overall strength.