Which of the following represents an 8-second inter-breath interval?

• A. 4 seconds
• B. 6 seconds
• C. 8 seconds
• D. 12 seconds

Answer: (C)

An inter-breath interval is the time between the end of one breath and the start of the next. If that pause lasts eight seconds, the breathing rate is about 60 divided by eight, which is roughly 7.5 breaths per minute. In the list, eight seconds is the duration that matches the requested eight-second interval. The other options would correspond to different breathing rates (four seconds about 15 breaths per minute, six seconds about 10 bpm, twelve seconds about 5 bpm).