I came across this by somebody from Iyenger yoga :-
A quickened heart beat may be the result of the specific asanas you’re referring to. Backbends (Urdhva Mukha Svanasana/upward facing dog pose, Ustrasana/camel pose, etc.) have an invigorating affect on the body which may increase your heart beat. Forward bends have the opposite affect, slowing the heart beat, and making them the ideal counter pose for backbends. ; If you suffer from anxiety, or are generally quite hyper, using yoga to increase your heart beat may worsen these conditions. If you suffer from fatigue or depression, an increased heart beat may be helpful.
This probably implies that one should rest between the increasing heart beat asanas and probably the reason behind doing one counterpose after a pose. Is it all right to do three backward bending poses and then do three forward bending posesI? I only do 3-4 minutes of savasan after a 15 minute asana session and have never been particular about resting between asanas.
I googled for Do;s and don’ts of yoga but the results revealed general guidelines like when to do and when not to do, what to ear and things like that. What about some special do’s and don’ts like the one above. From what I remember, Inversions like Sarvangasana should not be done by people with high blood pressure, People with slip disc or spinal problems should not do forward or backward bending asanas(I am not too sure). If somebody can contribute to more specific and special do’s and don’ts of Asana and Pranayam,especially what not to do for different medical problems(better to know at one place), I would appreciate that greatly.