Senior walking

I'm 68 years old and walk 30 to 45 minutes 3 to 4 times a week at about 5.5km/h (3.4mph). Resting heart rate averages 68 bpm. AI (Claude and Gemini) tell me this the heart of an athlete. I'm definitely not an athlete. Aside from walking, I shovel snow (I'm in Toronto, Canada) and spend time gardening in summer. How much should I trust AI?