NEW DELHI: Do your otherwise active grandparents find it difficult sometimes to climb stairs or go out to buy the groceries? Check their blood pressure.

High blood pressure ' blood pushing against the walls of the arteries each time the heart beats ' has till now been synonymous with stroke, heart failure, kidney failure and coronary artery disease. But doctors now say elevated blood pressure, specifically systolic blood pressure ' BP when the heart is contracting ' increases the risk of disabilities later in life, such as the inability to lift objects, walk up or down stairs, or bathe.

In a study reported in the November 20 issue of Hypertension : Journal of the American Heart Association, a team of doctors from Harvard Medical School confirmed this trend.

"This adds another dimension to how we think about hypertension," said Ihab Hajjar, lead author of the study. "We always think of it as a risk factor for CVDs and heart attacks. But this study shows elevated blood pressure also tends to affect our independence and functional abilities."

Reacting to the study, senior cardiologist of Apollo Hospital, Deepak Natarajan, told TOI: "High BP is an individual health risk for old people above the age of 70 years. It not only increases risk of heart diseases, but also causes dementia and limits cognitive functions. Controlling BP is the single most important factor. For those aged above 70 years, BP should be around 140/80 mmHg. They must not miss their BP medications, reduce their salt intake and do meditation."

The study has tremendous connotations for India where over 10 crore adults suffer from high BP. Some estimates say the disease is presently affecting about 32 million rural Indians and 34 million urban Indians. What's worse, India will soon have a tremendous volume of aged population.

According to the 2006 World Population Prospects, by 2050, the number of Indians aged above 80 will increase more than six times from the current figure of 78 lakh to nearly 5.14 crore. The number of people over 65 years of age in the country is expected to quadruple from 6.4 crore in 2005 to 23.9 crore.

For the Harvard study, researchers analyzed data from the Charleston Heart Study, which began in South Carolina in 1960 and collected its last survival data in 2001. The researchers investigated hypertension as a potential reason for why people age differently. Hajjar and his colleagues analyzed data from 999 study participants.

The researchers classified study members as normal (BP less than 140/90 mm Hg without using BP drugs) or hypertensive (BP at or above 140/90 mm Hg or taking medications to control it). Functional tests measured everything from physical strength (pushing, pulling, lifting) to mobility indexes (walking, using a wheelchair), to personal-hygiene ability (bathing, grooming, dressing).

The team then found that increases in systolic BP over time were associated with functional disability, even among those who are stroke-free with no other major diseases linked to high BP.