Adult CPR comes down to pushing hard and fast on the center of the chest at a rate of 100 to 120 compressions per minute, with each compression at least 2 inches deep. If someone collapses and isn’t breathing normally, starting chest compressions immediately is the single most important thing you can do to keep blood flowing to their brain and heart until paramedics arrive.
The 2025 American Heart Association guidelines reinforce that CPR should be performed right where the person is found, as long as it’s safe to do so. You don’t need certification or special equipment. Here’s exactly what to do.
Step 1: Check for Responsiveness
Tap the person firmly on both shoulders and shout, “Are you okay?” You can also rub your knuckles hard against their breastbone. If they don’t respond and aren’t breathing normally (gasping doesn’t count as normal breathing), assume they’re in cardiac arrest. This entire check should take only a few seconds.
Step 2: Call 911 Immediately
If you’re alone, call 911 before starting compressions. Put your phone on speaker so you can talk to the dispatcher while you work. If someone else is nearby, point directly at them and say, “You, call 911.” Also ask them to find the nearest AED (automated external defibrillator), which are commonly mounted on walls in gyms, airports, offices, and schools.
The dispatcher can walk you through CPR in real time if you’re unsure of any step.
Step 3: Start Chest Compressions
Position the person flat on their back on a firm surface. Kneel beside them so their chest is roughly at the level of your knees. Place the heel of one hand on the center of their breastbone, just below the nipple line. Stack your other hand directly on top and interlace your fingers.
Lock your elbows straight and position your shoulders directly over your hands. Use your upper body weight, not just your arms, to push straight down at least 2 inches into the chest. Then let the chest come all the way back up before the next compression. This full recoil is critical because it’s what allows the heart to refill with blood between pushes. Leaning on the chest between compressions, even slightly, reduces blood flow to the brain and heart.
Push at a rate of 100 to 120 compressions per minute. A helpful reference: that’s roughly the tempo of the song “Stayin’ Alive” by the Bee Gees. Count out loud if it helps you keep pace.
Hands-Only CPR vs. Traditional CPR
If you’re an untrained bystander or uncomfortable giving rescue breaths, hands-only CPR (compressions without mouth-to-mouth) is the recommended approach for any adult who suddenly collapses. It is effective because when someone’s heart stops, their blood still contains several minutes’ worth of oxygen. Continuous compressions keep that oxygenated blood circulating.
Traditional CPR with rescue breaths is better suited for situations where oxygen depletion is the core problem: drowning, drug overdose, choking, or a cardiac arrest that’s been going on for a prolonged period. It’s also preferred for children. If you’re trained and willing, the ratio is 30 chest compressions followed by 2 rescue breaths, repeated in cycles.
How to Give Rescue Breaths
After 30 compressions, tilt the person’s head back by lifting their chin with one hand and pressing their forehead down with the other. This opens the airway. Pinch the nose shut, seal your mouth over theirs, and blow for about one second, watching for the chest to visibly rise. Give a second breath, then immediately return to compressions. Each cycle of 30 compressions and 2 breaths should take roughly 24 seconds. Don’t over-inflate the lungs or blow too forcefully.
If the person is breathing but unconscious and has a pulse, provide one breath every 6 seconds (about 10 breaths per minute) without chest compressions.
Using an AED
An AED is a portable device that analyzes the heart’s rhythm and delivers an electrical shock if needed. It cannot hurt someone whose heart is in a normal rhythm because it won’t allow a shock to be delivered. You do not need training to use one.
When an AED arrives, turn it on and follow the voice prompts. Peel the adhesive pads from their packaging and stick them to the person’s bare chest exactly where the diagrams on the pads indicate (typically one on the upper right chest and one on the lower left side). The device will analyze the heart rhythm and tell you whether a shock is advised. If it says to shock, make sure no one is touching the person and press the shock button.
After the shock, resume chest compressions immediately. Do not stop to recheck for a pulse. Continue for two more minutes (about 200 compressions), then let the AED re-analyze. Repeat this cycle until paramedics take over or the person starts moving, breathing normally, or showing other clear signs of recovery. An AED works alongside CPR, not instead of it.
When to Stop CPR
Keep going until one of three things happens: emergency medical services arrive and take over, you become too physically exhausted to continue (if others are present, take turns every two minutes), or the person shows clear signs of life. Those signs include normal breathing (not gasping), purposeful movement, or any response to stimulation.
CPR is physically demanding. Compression quality drops significantly after about two minutes of continuous effort even when you don’t feel tired yet. If a second person is available, switch roles every two minutes with as little pause as possible.
Common Mistakes to Avoid
- Compressing too shallow. Most untrained rescuers don’t push hard enough. Two inches of depth requires real force. You may feel or hear ribs crack, and that’s normal. Broken ribs heal. Cardiac arrest without CPR is fatal.
- Compressing too fast or too slow. Faster than 120 per minute reduces the time for the chest to recoil, cutting blood flow. Slower than 100 isn’t enough to maintain circulation.
- Leaning on the chest between compressions. Let the chest fully spring back each time. Even resting a small amount of weight prevents the heart from refilling properly.
- Interrupting compressions. Every pause in compressions drops blood pressure to near zero, and it takes several compressions to build it back up. Minimize breaks to 10 seconds or less, even when switching rescuers or using an AED.
Legal Protection for Bystanders
Every U.S. state has some form of Good Samaritan law that protects bystanders who provide emergency care in good faith. These laws exist specifically because legislators recognized that fear of lawsuits was stopping people from helping. If you crack someone’s ribs during CPR, for example, that’s considered the kind of mistake any reasonable person might make while trying to save a life, and you’re protected from civil liability.
The protection applies as long as you’re acting voluntarily in a genuine emergency, the person consents (which is legally implied when someone is unconscious), and you aren’t grossly negligent or reckless. Performing CPR as you reasonably understand it easily meets that standard.