Unfortunately, learning breath control will not allow you to time travel and go to war with Daleks. However, mastering it and maximizing the strength of your diaphragm can give you two hearts. That's right, training your breath control can give you two hearts, but more on that later.
Breath training is a very important part of strength training. If you perform an exercise while holding your breath, you can truly harm yourself health wise. On the flipside, proper breathing during your exercise can keep your blood flowing properly, aiding the strength building process.
Even without strength training, breath training is great for its health benefits. Learning to breathe properly can help to reduce stress, improve concentration, improve digestion, improve blood flow, and cause many other overall improvements in physical vitality. This is where the power of the diaphragm comes in.
Your diaphragm is made up of skeletal muscle, so it can be strengthened through proper training. Exercising this muscle can increase the volume of oxygen that enters your lungs and the amount of blood that flows through your body because of its strength and surface area. Though your diaphragm may not operate like a heart or possess a beat, the volume of blood that it can help to move throughout the body, when fully controlled will be akin to you having a second heart, reducing a lot of strain on your actual heart. This is not to be confused with abdominal or belly breathing.
A good way of training your diaphragm is using the stomach vacuum. This is performed by exhaling until your lungs are empty, then drawing your stomach cavity inwards, as if to inhale without actually drawing in air. This helps to massage the internal organs and increase diaphragmatic strength. This should be a part of every strength training regimen, and performing a stomach vacuum or diaphragmatic breathing before a workout or early in the morning can give you an energy boost. Breath control will optimize your health in great ways overall.