Final answer:
The workout you described is considered vigorous, as indicated by your inability to maintain a conversation and a heart rate of 176 BPM after running, which aligns with vigorous-intensity levels.
Step-by-step explanation:
Based on the information provided, your workout would be classified as vigorous. The Talk Test is a simple way to measure the intensity of your workout and it indicates that if you cannot say more than a few words without pausing for breath, you are engaging in vigorous-intensity activity.
Since you mentioned that after running 2 miles you had a heart rate of 176 BPM and were not able to have a conversation due to heavy breathing, this clearly aligns with the vigorous-intensity activity definition. Moreover, healthy young individuals may reach up to 150 bpm during exercise, and vigorous activities often result in heart rates that are higher still, supporting your experience post-run as being part of a vigorous workout.