CBSE Class 7 Answered

Body size, weight and activity level influence normal breathing rates. But age is the factor most commonly used to determine normal values. Normal breathing rate ranges from as high as 30 to 60 breaths per minute at birth to as low as 12 to 16 breaths per minute at age 18. This means that the breathing rate in children is higher as compared to the adults. This is due to the fact that the infant’s body is growing rapidly and their body metabolism is high. This requires more oxygen which is achieved with the help of supply of more oxygen to the body. Hence, the breathing rate is high to compensate for the increased demand for oxygen in the body.