The American Heart Association (AHA) recommends 100–120 compressions per minute for adult CPR. This rate maximizes blood flow while allowing the heart to refill between compressions. Rates above 120 BPM may reduce compression depth and effectiveness.

Hands‑Only CPR is a simplified form of CPR that focuses solely on chest compressions — no rescue breaths. It is recommended for untrained bystanders or situations where rescue breaths are not feasible. It is equally effective as conventional CPR for adult cardiac arrest in the first few minutes.

For adults, compressions should be at least 2 inches (5 cm) deep but no more than 2.4 inches (6 cm). For children, about 2 inches (5 cm). For infants, about 1.5 inches (4 cm). Proper depth ensures adequate blood circulation.

Continue CPR until emergency medical services arrive, an AED becomes available, the person shows signs of life (breathing, movement), or you are physically exhausted and unable to continue. Do not stop prematurely — sustained compressions are critical for survival.

Use Hands‑Only CPR for adult victims of sudden cardiac arrest when you are untrained or unwilling to give rescue breaths. Use traditional CPR (30:2) for infants, children, drowning victims, or drug overdose situations where breathing problems likely caused the arrest. Trained responders should follow their training protocols.

Yes! This metronome is an excellent training aid for CPR practice. It helps you internalize the 100–120 BPM rhythm. However, it should be used as a supplement to proper CPR certification training. In a real emergency, focus on the victim — use the metronome's rhythm in your head by remembering songs like "Stayin' Alive."