How to Perform CPR on Adults: A Step-by-Step Guide for Bystanders

Knowing how to perform CPR on adults means knowing a short sequence well enough to run it under stress: recognize cardiac arrest, call for help, push hard and fast on the chest, use an AED, and keep going until professionals take over. This guide walks through each step, including hand placement, depth, and rhythm. You need a firm surface, your own two hands, and a phone. No certification is required to help, though a hands-on class makes these skills far more reliable.

Two terms first. Cardiac arrest is an electrical failure in which the heart stops pumping effectively. A heart attack is a blocked artery, and the person is usually awake and talking. A heart attack can lead to cardiac arrest, but they are not the same thing, and CPR is for cardiac arrest.

Step 1: Check the Scene and the Person

Before you touch anyone, look around for anything that could injure you too. Common hazards include moving traffic, water, downed power lines, fire, smoke, and unstable structures. If you become a second victim, nobody gets help. Move the person only if staying put is clearly unsafe, such as lying in a roadway, and then move them the shortest distance necessary.

Once the area is safe, test responsiveness. Kneel beside the person, tap them firmly on the shoulders, and shout, "Are you okay?" Use a loud voice. Someone who is asleep, intoxicated, or in a faint will usually react to noise and touch with eye opening, words, or movement.

If there is no response, treat it as an emergency and move on immediately. The most common mistake here is hesitating. Bystanders sometimes spend a minute wondering whether the person is just sleeping, whether they should step in, or whether they will do something wrong. Give this check a few seconds, no more.

If you are unsure whether the person is in cardiac arrest, act as though they are. Starting CPR on someone who turns out not to need it is a far smaller problem than withholding it from someone who does. A person who is unresponsive and not breathing normally is, for practical purposes, in cardiac arrest.

Many people worry about legal exposure. Good Samaritan laws protect rescuers in most places, but the details vary by state. If you live or work in Washington or California, check the current rules for your state, since these laws can change. In general, they are written to encourage people to help in good faith.

Step 2: Call 911 and Get an AED

Do not shout a general request for help and hope someone responds. People in a crowd often assume someone else has already called. Point at one specific person and give a clear instruction: "You in the blue jacket, call 911 and bring an AED." Then point to a second person and send them to look for an AED if one might be nearby.

An AED, or automated external defibrillator, is a portable device that analyzes the heart's rhythm and delivers a shock if one is needed. AEDs are often mounted on walls in gyms, offices, schools, airports, shopping centers, and community buildings, usually in a marked cabinet. If you work in a facility, learn where yours is before you ever need it.

If you are alone, call 911 yourself and put the phone on speaker. Set it down next to you so both hands are free. Do not leave the person to search for an AED unless you know exactly where one is and it is very close.

Stay on the line. Dispatchers are trained to coach callers through CPR, and they can count compressions with you, tell you when to switch, and relay what responders need to know. Follow their instructions and let them end the call. If a bystander is making the call for you, ask them to put it on speaker and report back what the dispatcher says.

Be ready to answer a few questions: the exact address or nearest cross street, whether the person is awake, and whether they are breathing. Answer briefly. Information that helps crews find you matters, but it should not delay the next step.

Step 3: Check for Normal Breathing and a Pulse

With the person on their back, look at the chest for no more than 10 seconds. You are watching for the chest to rise and fall in a regular pattern. Tilting the head back slightly can help you see and hear better.

The key phrase is normal breathing. Many people in the first minutes of cardiac arrest make gasping, snorting, or snoring sounds. This is called agonal breathing. It is a reflex, not effective breathing, and it does not mean the person is fine. It is easy to mistake for breathing, and it is one reason bystanders delay CPR. If the breathing is irregular, noisy, or gasping, treat it as no breathing.

Trained healthcare providers check for a pulse during the same 10 seconds, usually at the carotid artery in the neck. Lay rescuers can skip the pulse check. Pulses are hard to find, even for experienced people, and fumbling for one wastes time. If the person is unresponsive and not breathing normally, begin CPR.

If the person is breathing normally but unresponsive, do not start compressions. Stay with them, keep the line to 911 open, and watch their breathing. If there is no suspicion of spinal injury, and you are trained to do so, you can roll them onto their side to keep the airway clear. Recheck breathing regularly, because their condition can change quickly. If breathing stops or becomes abnormal, start CPR at once.

Step 4: Position Your Hands and Body for Compressions

Compressions work only against a firm, flat surface. If the person is on a bed or sofa, slide them to the floor if you can do so quickly. Lay them on their back and kneel beside their chest, with your knees about shoulder width apart and close to their body.

Find the lower half of the breastbone, which sits in the center of the chest between the nipples. Place the heel of one hand there. Put your other hand on top and either interlace your fingers or lift them so that only the heel of your bottom hand touches the chest. Keeping your fingers off the ribs focuses the force on the breastbone.

Then set your body up so that gravity does the work:

Straighten and lock your elbows.

Bring your shoulders directly above your hands, so your arms form a vertical column.

Hinge at the hips, not the waist or the elbows, so your upper body weight drives each push.

If your arms bend or your shoulders drift behind your hands, you will tire quickly and lose depth. Many rescuers find that they need to shuffle closer than feels natural.

Bare the chest if you can. Move or cut clothing aside quickly, but do not delay compressions for more than a moment. Bare skin matters later, because AED pads must stick directly to it. If you are in a position to remove a bra with metal underwire, do so before applying pads.

Step 5: Give High-Quality Chest Compressions

Begin pushing straight down. For adults, both the American Heart Association and the American Red Cross call for a depth of at least 2 inches (about 5 cm) and no more than 2.4 inches (6 cm). Aim for a rate of 100 to 120 compressions per minute. Guidelines are reviewed periodically, so a certified course will give you the latest figures. A song with a matching tempo, such as "Stayin' Alive," can help you hold the pace.

Depth and rate are only part of quality. Two other elements matter just as much:

Full chest recoil. Let the chest come all the way back up after each push. Recoil lets the heart refill with blood. Leaning on the chest between compressions prevents this.

Minimal interruptions. Every pause stops blood flow to the brain and heart. Keep any pause as short as possible.

Compressions are tiring. Fatigue sets in within a couple of minutes and quality drops, often without the rescuer noticing. If another person is present, switch about every 2 minutes, or sooner if you feel yourself slowing. Make the swap quickly, in a few seconds, with the new person ready beside you.

The most common mistakes are:

Pushing too shallow, usually from fear of hurting the person.

Bending the elbows and using arm strength alone.

Slowing down, or stopping to check whether the person has revived.

Resting a hand or body weight on the chest between pushes.

It helps to know that rib fractures can happen, especially with proper depth. That is an accepted risk. Broken ribs heal; cardiac arrest without CPR usually does not end well. Also, CPR does not restart the heart on its own. It keeps blood moving to the brain and organs until a defibrillator and advanced care can address the underlying rhythm.

Step 6: Add Rescue Breaths if You Are Trained

If you have been trained in CPR and are willing to give breaths, use cycles of 30 compressions followed by 2 breaths. If you are untrained, or uncomfortable giving breaths, do Hands-Only CPR instead. That means continuous compressions, with no pauses for breathing, and it is the recommended approach for untrained adult bystanders. It is far better than doing nothing.

To give breaths, follow these steps after the 30th compression:

Open the airway with a head tilt and chin lift: one hand on the forehead tilting the head back, the fingertips of the other lifting the chin.

Pinch the nose closed.

Make a seal over the person's mouth with yours, or use a face shield or pocket mask if you have one.

Give a breath over about 1 second, watching for the chest to rise.

Take a breath yourself, then give the second breath the same way.

Each breath should be just enough to make the chest visibly rise. Forceful or excessive breaths can push air into the stomach, which can cause vomiting and complicate things. If the chest does not rise, reposition the head, reopen the airway, and try again with the next breath. Do not spend long troubleshooting. If it still does not work, go straight back to compressions.

Keep the entire pause for breaths under 10 seconds. Then place your hands back in the same position and resume compressions immediately. A face shield or pocket mask is a reasonable item to keep in a first aid kit, car, or workplace emergency station, because it adds a barrier and makes breaths feel less awkward for many rescuers.

Step 7: Use the AED and Continue Until Help Takes Over

When an AED arrives, keep compressions going while someone opens it. Turn the device on and follow the voice prompts. Attach the pads to bare, dry skin as shown in the pictures on the pads, one on the upper right chest and one on the lower left side. If the chest is wet, dry it quickly. If there is excessive hair, a razor in the AED kit can help, but do not delay long.

When the AED says it is analyzing, make sure nobody is touching the person. Say "Clear" loudly and look to confirm. If the device advises a shock, check again that everyone is clear, then press the shock button. As soon as the shock is delivered, or if the AED says no shock is advised, resume compressions immediately. Do not wait to see whether the person responds. The AED will prompt you to pause again for another analysis about every 2 minutes.

Continue CPR until one of these happens:

Emergency medical services arrive and take over.

The person starts moving, speaking, or breathing normally.

An AED prompts you otherwise.

You are too exhausted to continue safely, and no one can replace you.

The scene becomes unsafe.

When responders arrive, give them a short, clear handoff. Tell them what happened and when you found the person, how long CPR has been going on, whether an AED was used, and how many shocks were delivered. Mention anything you know about the person's medical history. Then step back and let the team work. Afterward, it is common to feel shaken. Talking with someone you trust, or with your workplace's support resources, is a normal part of recovering.

Turning a Memorized Sequence into a Practiced Skill

Adult CPR is a sequence you can repeat from memory: check, call, compress, breathe if trained, shock if advised. Reading it is a start, but the skills hold up under stress only when you have practiced them. A hands-on course lets you work on manikins, get feedback on depth and rhythm, and learn how to use an AED and barrier devices. Certifications generally need renewal every two years, and your instructor can confirm the current requirements.

Taylored Instruction offers courses through both the American Red Cross and the American Heart Association, with personalized instruction for individuals, workplaces, and healthcare professionals in the Vancouver, WA, Portland metro, and San Luis Obispo, CA areas. Don't wait until an emergency happens. Get the life-saving certification you need today. Register for a CPR, First Aid, or Lifeguarding class and gain the confidence and skills to respond when it matters most.