When giving chest compressions to an adult, you should push hard and fast in the center of the chest at a rate of 100 to 120 compressions per minute, pressing down at least 2 inches (5 cm) deep. These core numbers, along with proper hand placement and full chest recoil between compressions, determine whether your effort actually moves blood through the body. Here’s what you need to know to do it effectively.
Where to Place Your Hands
Place the heel of one hand on the breastbone, just below the nipples. Put your other hand directly on top of the first, interlocking your fingers. Keep your arms straight and position your shoulders directly over your hands so you’re pressing straight down. The 2025 AHA guidelines specifically recommend that the person’s torso be at approximately the level of your knees, which means if someone collapses at home, getting them onto the floor is usually the right move.
Locking your elbows and using your upper body weight rather than your arm muscles is the key to sustaining effective compressions. Bending your elbows wastes energy and makes it much harder to hit the right depth consistently.
Depth, Rate, and Recoil
The current guideline target is a compression depth of at least 2 inches (50 mm). However, a large study published in Circulation found that peak survival actually occurred at a depth of about 45.6 mm, within an optimal range of roughly 40 to 55 mm (about 1.6 to 2.2 inches). Pushing too shallow fails to circulate blood. Pushing too deep increases injury risk without improving outcomes. For most people, aiming for a solid 2 inches is a practical and effective target.
The rate should be 100 to 120 compressions per minute. A useful mental trick: this matches the tempo of the Bee Gees’ “Stayin’ Alive” or Beyoncé’s “Crazy in Love.” Compressing faster than 120 per minute tends to reduce depth, which defeats the purpose.
Between each compression, let the chest come all the way back up to its normal position. This full recoil creates a vacuum effect inside the chest that draws blood back into the heart, refilling it for the next compression. If you lean on the chest between pushes, you cut off that refilling process and reduce blood flow even when your compression depth looks fine.
Compressions Only vs. Compressions With Breaths
If you’re untrained or uncomfortable giving rescue breaths, hands-only CPR (compressions without breaths) is the recommended approach. The AHA encourages this for bystanders because it simplifies the process and makes people more likely to act at all, which is the single biggest factor in survival.
If you’re trained in CPR, the standard ratio is 30 compressions followed by 2 rescue breaths, repeated in cycles. A meta-analysis found no significant difference in survival outcomes between compression-only and standard CPR for out-of-hospital cardiac arrest overall, though one European study did find higher survival-to-discharge rates when bystanders added breaths. The 2025 guidelines reaffirm that 30:2 cycles are reasonable for both lay rescuers and healthcare professionals.
When giving breaths, the updated guidance is to deliver enough air to produce visible chest rise, while avoiding both too many breaths and breaths that are too large. Over-ventilating can increase pressure in the chest and actually reduce blood flow.
Why Surface Matters
A soft surface absorbs compression force that should be going into the chest. In manikin studies, a mattress can absorb up to 57% of compression force, dramatically reducing effective depth. That said, research comparing firm hospital mattresses and firm home mattresses to the floor found relatively small differences in actual compression depth (around 2 to 5 mm). The practical takeaway: a firm mattress isn’t ideal but isn’t a disaster. A soft, pillow-top mattress or couch cushion is a real problem. When possible, get the person onto the floor.
Managing Fatigue
Chest compressions are physically exhausting, and quality drops faster than most people realize. Current guidelines recommend switching rescuers every 2 minutes, or sooner if you feel fatigued. Recent research suggests that rotating every 1 minute instead of every 2 actually improves compression depth and reduces fatigue. If you’re alone, there’s no option to rotate, but knowing that your compressions will degrade over time can help you stay mentally focused on pushing hard enough as minutes pass.
Compression-only CPR tends to cause fatigue faster than standard CPR with breaths, since the brief pause to ventilate gives your muscles a few seconds of recovery. If you’re performing hands-only CPR solo for several minutes, expect your arms and shoulders to burn. Push through it. Even degraded compressions are better than none.
Minimizing Pauses
Every second you stop compressing, blood flow to the brain and heart drops toward zero. The AHA sets a target called chest compression fraction: at least 60% of total resuscitation time should be spent actively compressing. That means pauses for breaths, rhythm checks, or switching rescuers need to be as brief as possible. When you do stop to give two breaths in a 30:2 cycle, aim to keep that interruption under 10 seconds.
Rib Fractures and Other Injuries
Effective chest compressions frequently cause rib fractures. A systematic review and meta-analysis found that about 55% of adult cardiac arrest patients who received CPR had rib fractures, and roughly 24% had a fractured breastbone. Multiple rib fractures occurred in about half of those with any fracture at all. More serious injuries like flail chest (where a section of ribs breaks free from the chest wall) occurred in about 4% of cases.
These numbers can sound alarming, but they reflect the force required to actually pump blood through someone’s body from the outside. A person in cardiac arrest will die without compressions. Broken ribs heal. If you feel a crack or pop while compressing, confirm your hand placement is correct and keep going.
CPR for Adults With Obesity
The 2025 guidelines added a new recommendation: CPR for adults with obesity should use the same techniques as for any other adult. The same hand position, the same depth target, the same rate. No modifications are needed, though reaching adequate depth may require more physical effort from the rescuer.