Complex question. Many things increase blood flow like physical exercise or even alcohol. While being active for sure is healthy, alcohol combines the positive and the negative so the effect will not be measurable.
Apart from that: caffeine is the only controversial thing in coffee (other studies report different results). Decaf is healthy without doubt. For old people caffeine has no effect on sleeping so we could recommend it for brain health. If you can still feel an effect on your sleep, do what feels best for you.
Iirc the causality is thought to be about opening vesicles and increasing blood flow in the brain.
Ah interesting. Can that be done equally without caffeine?
Complex question. Many things increase blood flow like physical exercise or even alcohol. While being active for sure is healthy, alcohol combines the positive and the negative so the effect will not be measurable.
Apart from that: caffeine is the only controversial thing in coffee (other studies report different results). Decaf is healthy without doubt. For old people caffeine has no effect on sleeping so we could recommend it for brain health. If you can still feel an effect on your sleep, do what feels best for you.
God made caffeine. Caffeine good for man. End. Of. Story.