Quick Answer

To perform CPR on an adult, place the heel of your hand on the centre of the chest and push hard and fast to a depth of at least 2 inches at a rate of 100 to 120 compressions per minute, allowing full chest recoil between each compression. After every 30 compressions, give 2 rescue breaths if you are trained and willing to do so. If you are untrained or uncomfortable with rescue breaths, hands-only CPR (compressions only) is still highly effective and far better than doing nothing.

2–3×

Higher survival odds when bystander CPR begins immediately

2 in.

Minimum compression depth for effective adult CPR

30:2

The compression-to-breath ratio for conventional CPR in adults and children

What You Will Learn

Why compression depth and rate matter more than most people expect
How to adjust CPR technique for adults, children, and infants
When hands-only CPR is appropriate and how to perform it correctly
How to open the airway and deliver effective rescue breaths
When to stop CPR and how an AED fits into the response chain
How acting fast can double or triple a cardiac arrest victim’s chance of survival

Why CPR Isn’t as Intimidating as It Looks

Four years ago, I stood at the front of my very first class, slightly nervous, with a Preston mannequin in front of me. Today, I’ve taught hundreds of students — from doctors and nurses to office workers and parents who just wanted to feel prepared. The one thing that never changes is how much people underestimate what they already know.

CPR isn’t as intimidating as it looks on TV. Here are the core techniques and tips I repeat in every class, because they are vital to saving a life. The American Heart Association puts it simply: acting quickly can double or triple a person’s chance of survival during a cardiac emergency. Someone in cardiac arrest has no pulse and no breath. The difference between doing something and doing nothing could be someone’s life.

Whether you’re a complete beginner or refreshing skills you haven’t used in a while, the fundamentals below are what I come back to in every class, because they are the ones that actually matter when it counts.

How to Perform CPR: Step-by-Step

Performing CPR correctly involves a cycle of chest compressions and rescue breaths. Before you start, make sure the environment is safe. A rescuer who gets hurt can’t help anyone. Once you’ve confirmed safety, check responsiveness, call emergency services, and then move through the steps below.

Step 1: Perform 30 Chest Compressions

Push harder than you think you should. This is the tip that surprises people the most. I always tell my students: if you’re not a little tired after 30 compressions, you’re probably not pushing hard enough. Yes, it can feel uncomfortable. Do it anyway.

First, make sure the person is lying flat on a firm surface — not a soft mattress, which absorbs the force and makes compressions nearly useless. Kneel beside them, place the heel of your hand in the centre of their chest, and put your other hand on top. Lock your elbows, get your shoulders directly over your hands, and press straight down using your entire body weight, not just your arms.

Push hard and fast in the centre of the person’s chest. For adults, you need at least 2 inches of depth. Most first-timers barely scratch an inch, which is not enough to keep blood moving to the brain and vital organs. Between each compression, allow the chest to fully recoil so the heart can refill with blood before the next push. Don’t lean on the chest.

How Deep Should CPR Compressions Be?

Patient	Depth	Hand Position
Adult	At least 2 inches (5 cm)	Two hands, heel on lower sternum
Child (1 yr to puberty)	At least 1/3 of chest depth	One or two hands on centre of child’s chest
Infant (under 1 yr)	At least 1/3 of chest depth	Two fingers or two thumbs on centre of infant’s chest

You may feel or hear something crack, especially in older patients. That’s a broken rib, and it doesn’t mean you stop. A broken rib is treatable. Cardiac arrest without CPR is not. Keep going.

Step 2: Give Two Rescue Breaths

I always tell my students: try to keep a plastic face shield in your pocket. You never know when you’ll need it. After 30 chest compressions, place your face shield over the person’s mouth and nose.

Open the airway by gently tilting the head back — one hand on the forehead, two fingers under the chin to lift it. This is the head-tilt chin-lift, and it matters because a relaxed jaw can block the airway completely. Pinch the nose, seal your mouth over theirs, and blow steadily for about 1 second while watching for the chest to rise visibly.

If the first breath goes in, give a second. If both breaths go in, immediately repeat the cycle of 30 compressions and 2 rescue breaths. If a breath doesn’t go in, reposition the head and try once more before resuming compressions. Don’t spend more time on the airway than you have to. Compressions are what keep the blood moving.

CPR with rescue breaths is particularly valuable when resuscitation continues for longer than a few minutes, because it replenishes oxygen in the blood. That’s what hands-on CPR training prepares you for — so the motion of delivering two breaths after 30 compressions becomes automatic before you ever need it in real life.

What Is Compression-Only CPR and When Should You Use It?

If you don’t have a breathing barrier device, or if you’re not comfortable giving rescue breaths for any reason, perform compression-only CPR — also known as hands-only CPR. This means skipping the rescue breaths entirely and just pushing hard and fast in the centre of the chest, without stopping.

Here’s why it works: oxygen already in the bloodstream can sustain the brain and vital organs for longer than most people realize. Keeping the blood pumping through continuous chest compressions is the most critical factor in those first few minutes of cardiac arrest. The American Heart Association is clear that hands-only CPR is recommended for untrained bystanders precisely because any CPR is better than none.

That said, hands-only CPR becomes less effective as time passes and blood oxygen continues to drop. If resuscitation needs to continue for more than a few minutes, conventional CPR with rescue breaths provides the oxygen the blood needs to sustain the brain. It’s one more reason why getting trained matters even if you already know the basics.

How Does an AED Fit Into CPR?

An automated external defibrillator (AED) and CPR are not competing options. They work together. CPR keeps oxygenated blood circulating to the brain and vital organs while the AED is retrieved and set up. The AED then addresses the underlying electrical problem in the heart that caused the sudden cardiac arrest.

One of the things I emphasize in every class is this: you don’t need to be trained to use an AED. The device provides voice prompts that walk you through every step — pad placement, analysis, and when to deliver a shock. The machine makes the decision. You just follow along. The American Heart Association specifically recommends that AED access not be limited to trained individuals, because getting to it quickly matters more than waiting for someone with a certificate.

When an AED is available, send someone for it while you continue compressions. Attach the pads, follow the prompts, stand clear when a shock is advised, then resume CPR immediately after. Accredited CPR and AED courses practice both skills together, which is important because muscle memory under stress is built through repetition, not reading.

How CPR Differs for Children and Infants

The approach changes slightly for smaller bodies, and this is something I spend real time on in class because the instinct to be cautious with kids can actually cause hesitation at the wrong moment. The principles are the same. The technique adjusts.

Children (1 Year to Puberty)

For children, use one or two hands depending on the child’s size, placed in the centre of the child’s chest. Push down at least one-third of the child’s chest depth. The 30:2 ratio applies here just as it does for adults. If you are alone and did not witness the child collapse, perform 2 minutes of CPR before calling for emergency help. If you witnessed the collapse, call first or have someone call while you start compressions.

Open the child’s airway by gently tilting the child’s forehead back — less aggressively than you would for an adult. Give rescue breaths with just enough air to see the child’s chest rise. You’re working with smaller lungs, so gentle and steady is the goal.

Babies and Infants (Under 1 Year)

For infants, place two fingers in the middle of the infant’s chest, just below the nipple line. Push down at least one-third of the infant’s chest depth and allow full chest recoil between each compression. If two rescuers are present, the two-thumb encircling technique is preferred for better depth and consistency.

To open an infant’s airway, gently tilt the head to a neutral position — not hyperextended, which can actually close the airway in very young infants. Cover both the infant’s mouth and nose with your mouth and give small, gentle puffs, just large enough to see the infant’s chest rise. The 30:2 cycle applies here as well. Maintaining that rhythm with an infant takes practice, which is exactly why doing it on an infant manikin in a certified first aid course matters so much for parents and caregivers.

When Should You Stop CPR?

Once you begin CPR, you should only stop or pause if one of the following occurs:

EMS personnel arrive on scene and take over
Another trained person relieves you
The scene suddenly becomes unsafe
You are too physically exhausted to continue
The person shows an obvious sign of responsiveness, like breathing or purposeful movement

CPR is tiring. After 2 minutes, compression quality starts to drop without you realizing it. If another bystander is available, swap out so the compressions stay deep and consistent. Fatigue is one of the most common reasons CPR loses effectiveness in longer resuscitation attempts.

Every time I see a student walk out of class standing a little taller, knowing they could actually do something if it came to it, that’s why I keep showing up. Knowing when to stop is part of that. So is knowing when to push through discomfort and keep going. Both are part of proper first aid and CPR training.

Workplace Readiness Note

Many Canadian provinces require workplaces to maintain a minimum number of employees with valid first aid and CPR certification. Certifications typically expire after 2 to 3 years. Confirming your team’s certification status proactively keeps your workplace compliant and prepared. Contact your provincial occupational health authority or review your jurisdiction’s OHS regulations for specific requirements.

Key Takeaway

Effective CPR comes down to three fundamentals: start immediately, push hard and fast in the centre of the chest, and minimize interruptions. For adults, compress at least 2 inches deep at 100 to 120 compressions per minute, then give 2 rescue breaths after every 30 compressions. If rescue breaths are not an option, hands-only CPR is still highly effective. Add an AED as soon as one is available. Acting quickly can double or triple a cardiac arrest victim’s chance of survival.

Practice CPR Before You Need It

Reading about CPR builds awareness. Hands-on practice builds confidence. A certified course lets you work through chest compressions, rescue breaths, and AED use on a manikin with a qualified instructor guiding your technique.

Find a CPR Course

Frequently Asked Questions: 2025 CPR Tips

Q1: What is the correct compression depth for adult CPR?

A: For an adult, chest compressions must reach a minimum depth of 2 inches (approximately 5 centimetres). Most untrained bystanders push to only about 1 inch, which is not sufficient to circulate blood effectively. To reach the required depth, position your shoulders directly over the victim’s chest, straighten your arms, and use your entire body weight pressing straight down rather than just arm strength. Allow full chest recoil between each compression so the heart can refill with blood. Compression depth is consistently identified as one of the strongest predictors of CPR quality.

Q2: How fast should I perform chest compressions during CPR?

A: The recommended compression rate is 100 to 120 compressions per minute for all age groups. This range is fast but not frantic. A commonly used pacing cue is the beat of the song “Stayin’ Alive,” which falls right in the middle of this range at approximately 103 beats per minute. Going faster than 120 compressions per minute reduces compression quality because the rescuer cannot achieve adequate depth or allow full chest recoil. Both rate and depth matter, and neither should be sacrificed for the other.

Q3: Is hands-only CPR as effective as CPR with rescue breaths?

A: Hands-only CPR is highly effective in the first few minutes after a witnessed adult cardiac arrest because residual oxygen in the bloodstream can sustain the brain and vital organs for a short period. For that window, continuous compressions without interruption for rescue breaths can produce outcomes comparable to conventional CPR. However, as time passes, blood oxygen levels decline and rescue breaths become increasingly important. For cardiac arrests in children, infants, or cases caused by drowning or respiratory failure, conventional CPR with rescue breaths is significantly more effective and should be used whenever possible.

Q4: What does full chest recoil mean and why does it matter?

A: Full chest recoil means completely releasing downward pressure after each compression so that the chest wall springs back to its natural position before the next compression begins. This recoil creates negative pressure inside the thoracic cavity, which draws blood back into the heart between compressions. If you lean on the chest or do not fully release between compressions, the heart cannot refill adequately and cardiac output drops significantly. Recoil is as important as depth. During CPR, consciously lift your hands slightly after each compression without losing hand position.

Q5: What is the correct CPR ratio of compressions to breaths?

A: For both adults and children aged 1 year to puberty, the standard ratio is 30 chest compressions followed by 2 rescue breaths. This 30:2 cycle is recommended by the American Heart Association and the Canadian Red Cross for single rescuers and is the ratio taught in accredited CPR courses. For infants under 1 year, the same 30:2 ratio applies in single-rescuer scenarios. When two trained rescuers are working together on an infant, the ratio changes to 15 compressions to 2 breaths. Healthcare providers delivering CPR to an intubated patient may use continuous compressions without pausing for breaths.

Q6: How do I perform CPR on an infant safely?

A: For an infant under 1 year old, place two fingers in the centre of the infant’s chest just below the nipple line. If a second rescuer is available, use the two-thumb encircling technique for better depth and recoil. Compress to at least one-third of the infant’s chest depth and allow full recoil. For the airway, gently tilt the head to a neutral position, covering the infant’s mouth and nose with your mouth. Give small, gentle puffs just large enough to see the chest rise. Use the same 30:2 ratio as for adults. Force must be carefully controlled to match the infant’s small chest.

Q7: Can CPR break ribs and should I still continue if it does?

A: Yes. Rib fractures during CPR are possible, particularly in older adults, and are a sign that compressions are reaching the required depth. If you feel or hear cracking during compressions, do not reduce your force or stop. A broken rib is a treatable injury. Cardiac arrest without adequate CPR almost always results in death or severe neurological damage within minutes. Continue compressions at the correct depth and rate, and let emergency medical services manage any rib injuries when they arrive. Reducing compression depth out of concern for ribs dramatically lowers the effectiveness of resuscitation.

Q8: How do rescue breaths work and how long should each one take?

A: Rescue breaths deliver oxygen directly into the victim’s lungs when they are no longer breathing on their own. After opening the airway with a head-tilt chin-lift, pinch the person’s nose closed, seal your mouth over theirs, and blow steadily for about 1 second while watching for the chest to rise visibly. If the chest rises, deliver a second breath the same way. If it does not rise on the first attempt, reposition the head and try again once before resuming compressions. Do not attempt multiple failed breaths. Excessive force can force air into the stomach, increasing the risk of vomiting and aspiration.

Q9: Does it matter what surface the person is lying on when I do CPR?

A: Yes. The victim must be on a firm, flat surface for CPR to be effective. If a person collapses on a soft mattress or cushioned surface, the compression force is absorbed by the surface rather than transmitted to the chest, making it nearly impossible to achieve adequate depth. Move the person to a hard floor if at all possible before starting CPR. On a bed, place a CPR board or a hard object under their back if one is immediately available. In a cardiac arrest, every second counts, so prioritize getting to a hard surface quickly rather than spending time on an elaborate repositioning.

Q10: Can I use an AED without any training?

A: Yes. AEDs are specifically designed to be used by untrained bystanders. The device provides clear, step-by-step voice prompts that guide the user through pad placement, analysis, and shock delivery. The AED itself determines whether a shockable rhythm is present and will not deliver a shock unless one is warranted. You cannot accidentally shock a person who does not need it. The American Heart Association recommends that access to AEDs not be restricted to trained personnel only, because the speed of deployment matters more than the operator’s certification level in a sudden cardiac arrest situation.

Q11: When should I call 911 versus starting CPR first?

A: For a witnessed adult collapse, call 911 or direct a bystander to call immediately, then begin CPR. For an unwitnessed child collapse where you are alone, the protocol differs: perform 2 full minutes of CPR first, then call for emergency help if no one else has done so. This is because pediatric cardiac arrests are more often caused by respiratory failure, and early CPR has a higher relative impact than for adults. Whenever other bystanders are present, the roles of caller and rescuer should be divided simultaneously to avoid any delay in either action.

Q12: What is the Chain of Survival in CPR?

A: The Chain of Survival is a framework from the American Heart Association that outlines the critical sequence of actions needed to maximise survival after sudden cardiac arrest. The links in the chain are: (1) early recognition and call for help, (2) early CPR to maintain blood flow, (3) rapid defibrillation with an AED, (4) advanced life support by emergency medical services, and (5) post-cardiac arrest care in hospital. Each link reinforces the next. Bystanders control the first three links. Bystander CPR is the single most impactful intervention available before EMS arrives, with the potential to double or triple survival rates when initiated immediately.

Q13: What does the C-A-B method in CPR stand for?

A: C-A-B stands for Compressions, Airway, and Breathing. The American Heart Association introduced this sequence to replace the older A-B-C (Airway, Breathing, Compressions) approach. The change prioritises chest compressions at the start of resuscitation because compressions are the most time-sensitive intervention and are often delayed when rescuers spend time on airway management first. Under C-A-B, a rescuer starts with 30 chest compressions immediately, then opens the airway and gives 2 rescue breaths, then cycles back to compressions. This sequence applies to adults, children, and infants in single-rescuer CPR scenarios.

Q14: Why is minimizing interruptions during CPR so important?

A: Every pause in chest compressions causes the blood pressure generated by CPR to drop rapidly, and it takes several compressions to rebuild it after a restart. Even a 10-second interruption can significantly reduce coronary perfusion pressure, the pressure that drives blood into the coronary arteries supplying the heart muscle itself. Current guidelines recommend that any pause in compressions be kept to an absolute maximum of 10 seconds. This is why rescue breath delivery should be efficient and why AED pad attachment is practised to be as fast as possible. The fraction of time that compressions are actually being delivered is called chest compression fraction, and a higher fraction correlates with better outcomes.

Q15: How is CPR training structured and what does a course typically cover?

A: Accredited CPR training courses are available for individuals, families, workplaces, and community groups. Most courses cover adult, child, and infant CPR, how to use an AED, how to manage a choking victim, and how to recognise the signs of sudden cardiac arrest. Many programs now use a blended learning format: participants complete the cognitive portion online at their own pace, then attend a shorter in-person skills session to practise compressions, rescue breaths, and AED use on a manikin with an instructor. Certifications are typically valid for 2 to 3 years, after which a renewal course is required to stay current with guideline updates.

Sources & Regulatory References

American Heart Association — 2020 Guidelines for CPR and Emergency Cardiovascular Care
Canadian Red Cross — First Aid and CPR/AED Program Guidelines
Heart & Stroke Foundation of Canada — CPR and AED Recommendations
Government of Canada — Workplace First Aid Requirements under the Canada Labour Code
Ontario Ministry of Labour, Immigration, Training and Skills Development — Occupational Health and Safety Act, First Aid Requirements Regulation (O. Reg. 1101)

This article is reviewed for clinical accuracy against current Canadian Red Cross and American Heart Association CPR guidelines. Content is intended for general educational purposes and does not replace formal first aid and CPR certification training.

Author

Azra Siddique

Background: Azra is a certified Red Cross First Aid & CPR Instructor, BLS Instructor, and Training Equipment Specialist at Coast2Coast First Aid and Aquatics. With a Master's in Chemistry and over twelve years of coaching and development experience at CIBC, she brings a rare combination of scientific precision and extensive corporate training expertise to her role.

Teaching Style: Drawing on an inherited gift for teaching—passed down from her mother, a school principal—Azra brings both depth and clarity to her classroom. She leverages her scientific background and corporate coaching experience to break down complex medical skills into accessible, practical lessons.

Instructor Mission: Azra's ultimate goal is to empower her students through confidence-building instruction. She is dedicated to ensuring that the vital life-saving skills she teaches truly resonate and stick with her participants long after the class comes to an end.