Those who try to bring down blood pressure levels should focus on reducing weight because obesity has a direct link with hypertension, says a new US study.

The study conducted by the University of Texas Southwestern Medical Center in as many as 35,000 people found that obese people are often likely to have a high systolic pressure.

While obese people were on top of the list of prospective hypertension patients, it was observed that those with high Body Mass Index (BMI) only had a small impact on blood pressure levels.

"Obesity is such a strong predictor of blood pressure or hypertension risk that having a normal body weight is really what's going to drive your blood pressure" according to researcher Dr. Susan Lakoski, a cardiologist.

To reach this conclusion, Lakoski and colleagues analyzed data collected over the last 20 years at the Cooper Clinic in Dallas. The investigators then compared the data in terms of BMI, fitness levels, and systolic blood pressure of all patients to see if the three measurements were linked.

They found that patients with a higher BMI often associated with having a higher systolic blood pressure. The researchers also noted that being fit had less of an impact on systolic blood pressure readings than BMI, irrespective of age and gender.

Only people having normal weight seemed to get much of a blood pressure benefit from having better fitness levels - possibly because fitness alone cannot overcome the negative effects of being obese, says Lakoski.

However, when considering the overall health and mortality risk, fitness plays a crucial role. "The ultimate thing we'd like to see is people obtain a lean body weight and start improving their fitness in the real world," she says in the study published in the American Heart Journal.