Luutje, you're over 40 now.. learn to find the middle gears (on a 1~5 scale). Since day and age you only seem to find either gear 1 (pretty passive) or gear nr. 5 (let's say, ADHD-like active). Gear 2, 3 or 4 are better/healthier for you, mate.
Um, saying this to myself cos I've overdone (5) the hedge trimming two bits this afternoon. My body says so and my knees and arms hurt quite a bit at the moment.