There always has been a lot of stress, but there used to be relaxed moments as well. The issue is that we don't calm down anymore.
Relevant video by Kurzgesagt – In a Nutshell: https://www.youtube.com/watch?v=Mo1A45ShcMo
Relevant video by Kurzgesagt – In a Nutshell: https://www.youtube.com/watch?v=Mo1A45ShcMo
Sapolsky goes into great detail about the positive affects of stress in short durations, then demonstrates how these positives turn into negatives all over our body after being stressed for too long. Highly recommend!