There's a mind body connection that an altered state can throw into disarray.

Under the influence of cannabis, one may be a lot more aware of physical pain, dehydration, and so on. The key word is aware. Suddenly becoming aware of the fact that you are stressed out, you are carrying tension, can lead to something of a latent processing effect of some of these suppressed or physically felt emotions.

However, if you're generally not tense, ingesting cannabis itself does not always raise the heart rate. I can validate this myself right now, given I wear an Apple Watch and can vaporize cannabis. Looking at my historical data, there is no relationship, and my resting heart rate remains in the 40s.

It's anecdotal, but at the same time we need to be careful with something that acts on the physical, the mental, and dare I say it, the spiritual. If we focus too much on one dimension, we lose the important synergy from processing all dimensions.