http://www.huffingtonpost.com/ornish-living/yoga-t...

High blood pressure (hypertension) describes when your blood pressure is regularly higher than recommended healthy levels. People often do not realise that they have high blood pressure as it rarely causes any obvious symptoms. However, it's one of the major risk factors for heart disease and stroke and is not something, therefore, to be taken lightly.

Stress and the way we respond to it can have a huge impact on our heart rate and blood pressure. This linked article explores how our stress response can up-regulate the sympathetic (fight or flight) nervous system.. When the sympathetic nervous system is up-regulated in such a way, it increases cortisol and adrenaline in the blood stream. This in turn increases our heart rate and constricts our blood vessels, which, in turn, increases our blood pressure to potentially health-compromising levels.

Yoga is potentially so efficacious for high blood pressure as it has been shown in multiple studies to stimulate parasympathetic (rest and digest) nervous system activity and to down-regulate sympathetic (fight or flight) arousal. A growing body of research is pointing to yoga's incredible benefits for stress within which the nervous system is strongly implicated alongside decreasing oxidative stress.

Calming yoga practices would appear to be the most beneficial for high blood pressure given their stimulation of the parasympathetic nervous system. Yin or a gentle hatha class are some examples with particularly useful pranayama practices including nadi sodhanan (alternate nostril breathing) and ujjayi ('ocean') breathing.