Why Blood Pressure gets High

Any pathological or physiological factors that strain the heart too much, or cause constriction of our blood vessels or cause retention of excessive water in our body, tend to increase our blood pressure - as the space within our blood vessels is limited. So, narrowing of blood vessels would thus naturally increase blood pressure. Same happens when our plasma volume increases 'coz of excessive fluid retention within the limited vascular space.

Factors affecting mild to moderate (reversible) increase in blood pressure : cold temperature, physical strain, excessive exercise, stress & anxiety, weight gain, lack of sleep, certain drugs and chemicals, sedentary lifestyle (lack of physical activity), pregnancy (gestational hypertension). tobacco and caffeine etc. Accordingly, most other factors being same, our blood pressure tends to go up somewhat in winters, and in colder climates, and tends to get a bit lower in summers, or upon moving to warmer, tropical climates. This happens because of temperature-related constriction or dilation of our blood vessels. And, such temperature-related fluctuations in blood pressure are far more common among the elderly, than among the younger populations.

How does excess body weight raise our blood pressure ? Our excess body weight is an expresssion of our increased stored body fat as ‘adipose tissue’. This is living fatty tissue with good blood supply of its own. We fail to appreciate that as little as 1 kg of adipose tissue in fact carries several kilometers long bed of blood capillaries - therefore considerably enhancing our circulatory pathway thorough which heart has to pump blood. If one is just about 10 kg overweight, just imagine the enhanced workload on our heart to propel blood through our thus extended circulatory system. To effectively attain this, our heart has to pump blood far more forcefully than what it does in non-obese subjects. Sooner or later, our heart, as a matter of compensatory physiological adaptation, keeps our blood pressure chronically raised, resulting in the general malaise of hypertension thus acquired. This is precisely why shedding of excessive body weight by suitable dietary and lifestyle modification normalises our otherwise raised blood pressure to quite some extent.