What Is the Maximum Interval for Pausing Chest Compressions?

The answer

The maximum time you should pause chest compressions is no more than 10 seconds. This is a core rule of high-quality CPR in the American Heart Association's Basic Life Support (BLS) guidelines. Whether you are pausing to deliver rescue breaths, check a rhythm, analyze with an AED, or switch compressors, the interruption must be brief — 10 seconds or less — before compressions resume.

The reason is blood flow. During cardiac arrest, chest compressions are the only thing generating circulation. It takes several compressions to build up enough pressure to push blood to the heart muscle and brain, and that pressure collapses almost immediately when compressions stop. Every pause forces you to start rebuilding that pressure from scratch. Keeping pauses under 10 seconds prevents perfusion from dropping to dangerous levels and improves the chance of restoring a pulse and protecting the brain.

Chest compression fraction

The 10-second rule connects to a broader measure called chest compression fraction (CCF) — the proportion of total resuscitation time actually spent doing compressions. AHA guidelines target a CCF of at least 60%, ideally 80% or higher. Minimizing the length and number of pauses is how you keep that fraction high. Long or frequent interruptions drag CCF down and worsen outcomes, which is exactly why each individual pause is capped at 10 seconds.

The other components of high-quality CPR

The 10-second limit works alongside the other pillars of effective compressions for an adult:

• Rate: 100 to 120 compressions per minute.
• Depth: at least 2 inches (5 cm) but no more than 2.4 inches (6 cm).
• Full recoil: let the chest come all the way back up between compressions so the heart can refill.
• Minimize interruptions: keep every pause to 10 seconds or less.

Rescuers should also switch compressors about every 2 minutes (or sooner if fatigued) to prevent tired hands from delivering shallow, slow compressions — and that switch itself should take under 10 seconds, ideally happening during a rhythm check.

The bigger picture

Everything about the 10-second rule comes back to keeping blood moving to the heart and brain with as little interruption as possible. Fast, deep, fully-recoiling compressions build perfusion; short pauses preserve it. When you must stop — for a breath, a shock, or a compressor swap — count it out and get back on the chest in under 10 seconds. Doing so keeps the compression fraction high and gives the patient the best possible chance of survival.