When providing rescue breaths to an adult, deliver one breath every 6 seconds (10 breaths per minute), with each breath lasting about 1 second. The key indicator that you’re delivering enough air is visible chest rise. These numbers come from the 2025 American Heart Association guidelines and apply to an adult who has a pulse but is not breathing normally.
When Rescue Breaths Are Needed
Rescue breaths are specifically for a person in respiratory arrest, meaning their heart is still beating but they’ve stopped breathing or are only gasping. This can happen during a drug overdose, drowning, severe allergic reaction, or choking that has been partially cleared. The situation is different from full cardiac arrest, where both the heart and breathing have stopped and chest compressions become the priority.
Before starting rescue breaths, check for a pulse at the side of the neck (the carotid artery). Spend no fewer than 5 seconds and no more than 10 seconds feeling for it. If you detect a pulse but the person isn’t breathing, rescue breaths alone are what they need. If there’s no pulse, you’ll need to begin full CPR with chest compressions.
How to Open the Airway
An unconscious person’s tongue can fall back and block the throat, so you need to open the airway before delivering any breaths. The standard method is the head-tilt, chin-lift: place one hand on the person’s forehead and gently tilt the head back while lifting the chin upward with the fingers of your other hand. This pulls the tongue forward and clears the air passage.
There is one important exception. If you suspect a neck or spinal injury (from a fall, car crash, or diving accident), tilting the head can worsen the damage. In that case, use a jaw-thrust maneuver instead: kneel behind the person’s head, place your fingers along the lower jawbone on both sides, and push the jaw forward without moving the head or neck. Research on cervical spine injuries shows this produces the least movement at the upper vertebrae compared to the head-tilt technique. If the jaw thrust doesn’t produce visible chest rise, switch to head-tilt, chin-lift anyway, because getting oxygen into the lungs takes priority.
Delivering Each Breath
Pinch the person’s nose shut with the hand that’s on their forehead. Make a complete seal over their mouth with yours, then blow steadily for 1 second. Watch the chest as you blow. If it rises visibly, pull away to let the air escape, then deliver the next breath after 6 seconds. If the chest doesn’t rise on the first attempt, re-do the head-tilt, chin-lift to reposition the airway and try again.
The amount of air you need to deliver is moderate, roughly 600 milliliters per breath, which is less than a full exhalation. A common mistake is blowing too hard or too fast. When air enters quickly under high pressure, it’s more likely to push past the valve at the top of the stomach rather than filling the lungs. Slow, steady breaths over that full 1-second window keep mouth pressure low enough that nearly all the air goes where it should.
Why Exhaled Air Still Works
A reasonable question is whether your exhaled breath contains enough oxygen to help someone. Room air is about 21% oxygen. The air you breathe out during rescue breathing contains roughly 16 to 17% oxygen. That’s lower, but it’s still more than enough to support blood oxygenation in someone whose lungs are otherwise healthy. The limiting factor in respiratory arrest isn’t the quality of the air, it’s the absence of breathing itself.
Avoiding Stomach Inflation
One of the most common complications during rescue breathing is gastric inflation, where air fills the stomach instead of the lungs. This happens when the pressure in the mouth exceeds the pressure of the valve (lower esophageal sphincter) that normally keeps the stomach closed off. A stomach full of air raises the risk of vomiting, which can then block the airway or enter the lungs.
Three things help prevent it. First, keep each breath to 1 second and deliver it gently rather than forcefully. Shorter, controlled breaths limit the time air has to slip past the stomach valve. Second, don’t over-inflate. Stop blowing as soon as you see the chest rise. Third, make sure the airway is properly opened. A partially blocked airway increases resistance in the lungs, which forces more pressure into the throat and redirects air toward the stomach.
If the Person Vomits
Vomiting during rescue breathing happens frequently. If it does, immediately roll the person onto their side to let fluid drain from the mouth. If you can see solid material blocking the airway, sweep it out with a finger. Then roll them back onto their back and resume rescue breaths, re-opening the airway with a fresh head-tilt, chin-lift. Don’t try to deliver breaths through vomit, as the priority is clearing the airway first, even if that means a brief pause.
Using a Barrier Device
If you have access to a pocket mask (a small, rigid mask with a one-way valve), use it. You place the mask over the person’s nose and mouth, seal it with both hands, and blow through the valve port. In a study comparing pocket masks to flat face shields, pocket masks produced visible chest rise 100% of the time, while face shields achieved it only 82% of the time. Pocket masks also delivered a higher volume of air per breath and caused shorter pauses in care. Face shields are better than nothing for personal protection, but they make it harder to form a tight seal and require more effort to ventilate effectively.
Reassessing Every 2 Minutes
While you continue delivering 1 breath every 6 seconds, pause approximately every 2 minutes to re-check the person’s pulse and look for signs of spontaneous breathing. If the pulse disappears, switch immediately to full CPR with chest compressions. If the person starts breathing on their own, stop rescue breaths, place them in a recovery position on their side, and monitor them until help arrives. During these pulse checks, keep the interruption as brief as possible, no more than 10 seconds, so the person isn’t left without ventilation for too long.
Rescue Breaths During Full CPR
If the adult has no pulse and you’re performing full CPR, the ratio changes. You deliver 30 chest compressions followed by 2 rescue breaths, then repeat. Each of those 2 breaths still lasts 1 second and should produce visible chest rise. The goal is to keep pauses for breathing as short as possible so chest compressions aren’t interrupted for more than a few seconds. With two rescuers, the same 30:2 ratio applies for adults unless an advanced airway device is in place.