The mark of a true professional is breath control. A great MC can effortlessly fire off a series of dizzying multi-syllable rhymes and never skip a beat. It's essential for sounding professional, pulling off impressive flows and rhyme schemes, and presenting a strong presence on the mic.
So how do the greats do it? Turns out there's a few tricks.
The number one rule for almost anything applies to breath control as well. The more you rap, the more you train your brain to subconsciously account for difficult portions of the verse and take breaths at appropriate spots. Over time you also condition your lungs to hold more air and you can rap unimpeded.Do you have to be in great physical shape? Not necessarily. Many rappers we associate with being overweight show amazing feats of breath control. That said, they do have the benefit of years of practice. Their brains are finely attuned and their lungs are much stronger than their overall image would suggest. All else equal someone who's athletic will have better breath control, but being out of shape isn't a prohibitive factor.
2. Punching in
Punching in is the practice of rapping a few bars, hitting stop on the record button - catching your breath, and then jumping back in where you left off. It's commonly done every 4 bars, and it's a great way to initially build your breath control. Even the great Big Pun would often only rap one bar at a time. A challenge of punching in is matching the vocal pitch and rhythm you left off with (otherwise it will sound uneven, and the "punch-in spots" will be obvious to the listener). A great engineer or producer can make punching in a seamless process, but it can also be done in a home studio using software like ProTools or Reaper.
Before you even step into the booth you can account for breath control in your lyrics. Part of this is knowing your own limitations as a rapper (or if your client's if you're ghostwriting). Trying to pull of a series of double time multi-syllable rhymes right out the gate (like Eminem on "Forever") is extremely challenging. You can sprinkle in impressive lines between parts where the flow changes, breaks down, or where you stretch out words. A secondary benefit of changing your flow for better breath control is that it keeps your delivery interesting and the listener engaged. You can also put pause marks "[--]" in your written lyrics to remind yourself where to take a breath or slow down.