When switching from the lower-sodium to a high-sodium diet, those who experienced a 5 percent or greater boost in their systolic blood pressure (the heart contraction measure represented by the top figure of a blood pressure reading) were deemed "high salt-sensitive."
Those reporting the most physical activity had a 38 percent lower risk of being highly salt-sensitive than the least active group. This group was the least likely to see a 5 percent or greater rise in their blood pressure in response to a high-salt diet.
Compared with the most sedentary group, those in the next-to-highest activity group had a 17 percent lower risk of salt-sensitivity, and those in the next-to-lowest activity group had a 10 percent lower risk.
The team concluded that engaging in physical activity has a "significant," independent and progressively healthful impact on the degree to which salt sensitivity relates to blood pressure.
The authors acknowledged that the study needs to be repeated. Also, experts note that research presented at meetings has not been subjected to the same type of rigorous scrutiny given to research published in peer-reviewed medical journals.
Still, "there's no reason to think these findings will not apply to a U.S. population. Stress factors for hypertension are the same for a Chinese and American population," said He.
"So the basic message here is, first we need to encourage the population to both lower their sodium intake and to increase their physical activity," He added. Those who can't increase their physical activity, perhaps because of age or disability, should still be encouraged to follow a low-sodium diet, "because sodium has a marked affect on blood pressure," He said.
Lona Sandon, a registered dietitian and assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, said that the findings highlight some of the well-known benefits of regular exercise.
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