Because second hand smoke can and will affect the lungs of everyone who is around, not just the smokers
It's more accurate, especially since heart rate is almost universally measures in beats-per-minute, than, say, timing your pulse for a [factor of 60] seconds (30 seconds, 20 seconds, 15 seconds, 12 seconds, etc.).
Answer:
morning fog
Explanation:
can't drive fast in the fog
