Do what works for your body!
While it's great to feel the increased heart rate, I would never try to keep up with my tall/slim boyfriend if he ever tried to power walk away from me. It may be all mental to think I couldn't, but I'd probably faint from exhaustion.
So, don't feel like you're under what other people consider normal. Increase your rate with time, IF you feel you can handle it.
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Perhaps misguided moral passion is better than confused indifference. - Iris Murdoch
