You can perform effective CPR using only chest compressions, no mouth-to-mouth needed. The American Heart Association recommends this approach, called hands-only CPR, for any bystander who witnesses an adult suddenly collapse. Survival rates are virtually identical: a large randomized trial in Sweden found 28.6% survival with compression-only CPR versus 28.4% with standard CPR that included rescue breaths.
Why Chest Compressions Alone Work
When someone’s heart stops, their blood still holds a substantial reserve of oxygen. The problem isn’t a lack of air. It’s that the blood has stopped moving. Pushing on the chest forces that oxygenated blood toward the brain and heart, buying critical time until paramedics arrive.
Chest compressions also act like a bellows, pushing a small amount of air in and out of the lungs with each push. That passive ventilation supplements the remaining oxygen in the bloodstream. For the first several minutes of a cardiac arrest in an adult, this is enough. Pausing compressions to deliver breaths actually interrupts blood flow, which can do more harm than good when oxygen levels are still adequate.
The Two Steps
Hands-only CPR has just two steps: call 911, then push hard and fast on the center of the chest. Here’s how to do each part well.
1. Call 911 Immediately
If someone collapses and isn’t breathing normally, call 911 right away or tell someone nearby to call. Put the phone on speaker so the dispatcher can guide you in real time. Every minute without CPR reduces the chance of survival, so don’t wait to see if the person “comes around.”
2. Start Chest Compressions
Kneel beside the person and place the heel of one hand on the center of their chest, on the lower half of the breastbone. A good landmark is slightly below an imaginary line drawn between the nipples. Place your other hand directly on top of the first and interlace your fingers.
Lock your elbows straight and position your shoulders directly above your hands. Use your upper body weight, not just your arms, to press down. Push at least 2 inches deep but no more than about 2.4 inches. After each compression, let the chest spring all the way back up before pushing again. This recoil phase is important because it lets the heart refill with blood between compressions.
Aim for a rate of 100 to 120 compressions per minute. Research on over 13,700 patients found that this range produces the best survival rates compared to slower or faster tempos. Keep going without stopping until paramedics take over or an AED (automated external defibrillator) becomes available.
How to Keep the Right Tempo
Counting to yourself works, but matching a familiar song is easier under stress. The classic recommendation is “Stayin’ Alive” by the Bee Gees, which sits right at about 104 bpm. But plenty of other songs land in the 100 to 120 range:
- “Billie Jean” by Michael Jackson (117 bpm)
- “Bad Romance” by Lady Gaga (119 bpm)
- “Eye of the Tiger” by Survivor (109 bpm)
- “I Wanna Dance With Somebody” by Whitney Houston (119 bpm)
- “Smells Like Teen Spirit” by Nirvana (117 bpm)
- “Can’t Stop the Feeling” by Justin Timberlake (113 bpm)
Pick one you know well enough to hear in your head. The specific song doesn’t matter as long as it keeps you in that 100 to 120 range.
Common Mistakes to Avoid
The most common error is compressing too shallowly. People worry about hurting the person, but compressions that are too light don’t generate enough blood flow. Studies show survival drops significantly when depth falls below about 2 inches. A cracked rib is survivable. A cardiac arrest without adequate compressions is not.
The second most common mistake is stopping. Fatigue sets in fast, often within two minutes. If someone else is nearby, take turns every two minutes to keep the quality of compressions high. When you switch, do it as quickly as possible. Even brief pauses let blood pressure in the brain and heart drop.
Finally, don’t lean on the chest between compressions. Keeping your weight pressed down prevents the chest from fully expanding, which limits how much blood refills the heart.
When Rescue Breaths Are Still Needed
Hands-only CPR is designed for the most common scenario: an adult whose heart suddenly stops due to a cardiac problem. But some situations involve a breathing problem first, meaning the blood’s oxygen supply is already depleted before the heart stops. In these cases, compressions alone may not be enough:
- Drowning: The lungs may be full of water, leaving very little oxygen in the blood.
- Drug overdose: Opioids and other substances suppress breathing, so oxygen levels drop before the heart fails.
- Infants and children: Pediatric cardiac arrest is almost always caused by a breathing problem, not a heart rhythm issue.
- Choking or airway blockage: If the airway was blocked long enough to cause collapse, oxygen reserves are gone.
- Asthma attacks or carbon monoxide poisoning: Both starve the blood of oxygen before the heart stops.
If you’re trained in conventional CPR, use a ratio of 30 compressions to 2 breaths for these situations. If you’re not trained, hands-only CPR is still far better than doing nothing. Dispatchers on 911 can walk you through what to do for the specific situation.
You’re Legally Protected
Every U.S. state has some form of Good Samaritan law that shields bystanders who provide emergency care in good faith. These protections apply whether or not you’ve had formal CPR training. The only exceptions involve gross negligence or intentional misconduct, neither of which applies to someone genuinely trying to help during a cardiac emergency.
This legal protection exists precisely because bystander CPR saves lives, and lawmakers don’t want fear of a lawsuit to stop people from acting. The American Heart Association has pushed for hands-only CPR in part because eliminating the mouth-to-mouth component removes a major barrier. People hesitate over concerns about disease transmission, the “ick factor,” or simply not knowing how to do rescue breaths correctly. Compression-only CPR sidesteps all of those concerns while delivering the same survival benefit for adult cardiac arrest.
Why Acting at All Is What Matters Most
Only about 40% of people who have an out-of-hospital cardiac arrest receive bystander CPR. The rest wait for paramedics, and by then, brain damage or death is far more likely. The single biggest factor in survival isn’t perfect technique. It’s whether someone starts compressions at all.
Hands-only CPR was designed to lower the barrier. Two steps, no mouth contact, no special equipment. If you see someone collapse and they’re not breathing, put your hands on their chest and push. That’s the whole thing.