Heart rate is measured by counting the number of beats per minute. Someone's normal heart rate depends on things like the person's age and whether he or she leads an active lifestyle. The resting heart rate decreases as people get older. Typical normal resting heart rate ranges are: 1  babies (birth to 3 months of age): 100â150 beats per minute. 2  kids 1â3 years old: 70â110 beats per minute. 3  kids by age 12: 55â85 beats per minute.
A respirator is a piece of protective respiratory equipment designed to protect the wearer from inhaling harmful particulate matter (as in dusts, including airborne microrganisms), fumes, vapors, or gases.
Sponsor Link. A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content of each breath. Oxygen is added to replenish the amount metabolised by the user.