Spirometry data CER analysis

Claim: My resting heart rate is within a healthy range, sitting slightly above the middle of the predicted resting band rather than pointing to a heart problem.\n\nEvidence: I measured my resting heart rate twice after sitting quietly for five minutes. The first reading was 78 beats per minute and the second was 74 beats per minute, for an average of 76. A typical predicted resting range for a healthy teenager is about 60 to 100 beats per minute, so both readings fall inside that band.\n\nReasoning: Resting heart rate reflects how efficiently the heart pumps blood while the body is at rest. A strong, well-conditioned heart pushes out more blood with each beat, so it can meet the body's oxygen needs with fewer beats per minute. My average of 76 sits comfortably inside the predicted range, which means my heart is meeting my resting oxygen demand without straining. The 4-beat difference between my two readings is small and is best explained by normal measurement variation, such as still settling down or miscounting by one or two beats, rather than by a real change in heart function. A single count near the high end of the range does not by itself signal disease, because the predicted band is wide on purpose to cover healthy people.\n\nFactor that could affect resting heart rate: Recent caffeine intake would raise resting heart rate for a while, because caffeine is a stimulant that makes the heart beat faster and can push a reading toward the top of the range even when the heart is healthy. Measuring before drinking coffee or energy drinks gives a truer resting value.