Mouth-to-mouth is still part of CPR, but it’s no longer expected of every rescuer. Current guidelines from the American Heart Association and international resuscitation bodies distinguish between situations where chest compressions alone are sufficient and situations where rescue breaths remain important. The short answer: for most adult cardiac arrests witnessed by a bystander, hands-only CPR (pressing hard and fast on the chest without giving breaths) is the recommended approach for untrained rescuers. But rescue breathing hasn’t disappeared from CPR. It still plays a critical role for children, infants, drowning victims, and overdose cases.
What Changed and Why
For decades, CPR training centered on the classic cycle: tilt the head, pinch the nose, blow two breaths, then do chest compressions. That changed in 2010 when the AHA began promoting hands-only CPR for bystanders. The reasoning was practical as much as medical. Studies in Sweden tracked bystander CPR rates over nearly two decades as compression-only CPR was gradually adopted into guidelines. Bystander CPR rates climbed from 40.8% in the early 2000s to 68.2% by 2017, driven almost entirely by more people performing the simpler, compressions-only technique.
The reluctance to put your mouth on a stranger’s was a real barrier. By removing that requirement for the most common type of cardiac arrest, guidelines made it far more likely that someone would step in at all. And doing something is dramatically better than doing nothing. A large Arizona study found that survival from out-of-hospital cardiac arrest was 5.2% when no bystander performed CPR, compared to 13.3% when bystanders did chest compressions only.
Why Compressions Alone Can Work for Adults
When an adult’s heart suddenly stops due to a cardiac problem (the most common scenario), their blood still contains a reasonable amount of oxygen. The immediate crisis isn’t a lack of air in the lungs. It’s that blood has stopped circulating. Chest compressions act as a manual pump, pushing oxygenated blood to the brain and heart. For the first several minutes, that existing oxygen supply can sustain vital organs if compressions keep the blood moving.
Pausing compressions to deliver breaths actually creates problems. Rescue breaths increase pressure inside the chest, which makes it harder for blood to flow back into the heart. Each pause in compressions also drops the blood pressure you’ve been building up. Research has shown that excessive ventilation during CPR limits the heart’s output and reduces the blood flow reaching the coronary arteries. For an untrained bystander, the time spent trying to deliver breaths (often incorrectly) can do more harm than good by interrupting the compressions that matter most.
When Rescue Breaths Still Matter
Not every cardiac arrest starts with a heart problem. In some cases, the heart stops because the person ran out of oxygen first. These situations are fundamentally different, and compressions alone aren’t enough.
Children and Infants
Respiratory problems, not heart rhythm issues, are the leading cause of cardiac arrest in children and infants. A child who stops breathing from choking, asthma, or another airway problem needs oxygen restored quickly. Large observational studies have shown that children who receive CPR with breaths (at a ratio of either 30:2 or 15:2 compressions to breaths) have better survival than those who receive compressions only. The AHA’s 2025 pediatric guidelines encourage lay rescuers to provide breaths along with compressions for infants and children if they are able and willing to do so.
Infant guidelines apply to babies under one year old. Child guidelines apply from age one until puberty. Once a person shows signs of puberty, adult guidelines take over.
Drowning
Drowning is a textbook case where rescue breathing is essential. The sequence in drowning moves from oxygen deprivation to respiratory arrest to cardiac arrest. By the time the heart stops, the blood is severely depleted of oxygen, so simply pushing it around the body with compressions won’t help much. The 2024 AHA focused update on drowning resuscitation states clearly that rescue breathing is associated with improved outcomes and should be provided as soon as possible. If a trained rescuer can safely deliver breaths while still in the water, doing so may prevent the situation from progressing to full cardiac arrest.
Drug Overdose
Opioid overdoses suppress breathing. Like drowning, the heart eventually stops because the body has been starved of oxygen, not because of an electrical problem in the heart. Rescue breaths are important in these cases for the same reason: the blood needs fresh oxygen, not just circulation.
What the 2025 Guidelines Recommend
The most recent international guidelines, published in 2025, maintain the same basic framework that’s been in place since 2020. For adults in cardiac arrest, CPR should start with compressions rather than breaths. The recommended ratio, when breaths are given, is 30 compressions followed by 2 breaths.
For untrained bystanders, hands-only CPR is the standard. Push hard and fast in the center of the chest at a rate of 100 to 120 compressions per minute. Don’t stop until emergency medical services arrive or an AED is available.
For trained lay rescuers, the guidelines encourage adding breaths to compressions. The AHA notes that CPR with breaths may lead to improved outcomes compared to compressions alone, even in adults. So if you’ve taken a CPR class and feel confident delivering effective breaths, doing so is reasonable.
For healthcare professionals, providing both compressions and ventilation is the standard for all adult cardiac arrests, regardless of the suspected cause. EMS personnel can use either the traditional 30:2 ratio or continuous chest compressions with breaths delivered at a rate of about 10 per minute without pausing compressions.
Compression-to-Breath Ratios at a Glance
- Untrained bystander, adult victim: Continuous chest compressions only (no breaths needed)
- Trained bystander, adult victim: 30 compressions, then 2 breaths
- Trained bystander, child or infant: 30 compressions, then 2 breaths (or 15:2 if two rescuers are present)
- Healthcare professional, any victim: 30:2 ratio, or continuous compressions with ventilation delivered without pausing
- Drowning or overdose victim: Breaths are a priority; begin rescue breathing as early as possible alongside compressions
The Bottom Line on Rescue Breathing
Mouth-to-mouth isn’t obsolete. It’s been moved from “always required” to “depends on the situation.” For the most common scenario, an adult who suddenly collapses from a heart problem, hands-only CPR is effective and far simpler to perform under stress. For children, drowning, and overdose, rescue breaths remain a key part of giving that person the best chance of survival. If you’re unsure or untrained, continuous chest compressions are always better than doing nothing. The Arizona data makes this stark: survival nearly tripled when bystanders performed compressions-only CPR compared to standing by and waiting for paramedics.