Many thanks for your advice Rob!
During my walks I use a heart rate monitor (with chest strap) and I do not go above 120 bpm (80% of my maximum heart rate would be 125). After reading your advice, I emailed my cardiologist asking him if I should reduce the intensity of my physical activity, he answered that what I do is OK.
From my walks, two Cyclamen purpurascens with
heart shaped (
) leaves...