Went for a long easy run, around 1 hour aiming for 7:15/km pace since I'm a beginner.

Ran around 8km and it was relatively easy and I could handle more, but I feel like my heart rate is a bit high, it's always like this at this pace. I'm 41 and the weather was around 28°C yesterday. Should I expect my heart rate to reduce naturally as I keep training? I'm running for 3 months and do around 4 runs each week