A respiration detector includes mouth guard 1 connectable via coupling portions 11, 25 to seat 2, having detection unit 3 including microphone and micro-processing circuitry to indicate a respiratory rate of the user. A transmission circuit proceeds with data transmission with an external device, for example wirelessly. Lamps 35 such as LEDs may be activated when breathing times reach a set value, such as 50%, 70% and 90% of the maximum breathing rate, as determined for example by multiplying the users BMI by a present coefficient. An app downloaded into the external device may allow input of the sex, age, height and weight of the user for conversion into BMI. A detection hole 26 may be aligned with the microphone and power switch and power indication lamp may be accessible via through-holes 311, 312. The user during exercise can know whether the current respiratory rate is normal in real time.
