Final answer:
A level above 600 pg/mL of BNP indicates severe limitations with the heart during activity and rest.
Step-by-step explanation:
A level of above 600 pg/mL of BNP indicates severe limitations with the heart during activity and rest. BNP, or B-type natriuretic peptide, is a hormone secreted by the heart in response to stress or heart failure. When the heart is not able to pump effectively, BNP levels rise, indicating severe limitations with the heart.