ALLERGY, RESPIRATORY
Combating Myths About Seasonal Allergies
New Spray Could Benefit Cystic Fibrosis Patients
Know Your Asthma Triggers
ALTERNATIVE MEDICINE
Acupuncture May Ease Depression During Pregnancy
Taking the Mystery Out of Hypnotherapy
Grapefruit Compound Inhibits Hepatitis C Virus
ANIMAL CARE
Animals Respond to Acupuncture's Healing Touch
Rest Easy. When It Comes to Swine Flu, Your Pet Is Safe
'Comfort Dogs' Come to Emotional Rescue
BONES & JOINTS
Study Shows Exercise Shields Against Osteoporosis
Arthritis Hits More Than Half of Diabetics
Put Your Best Foot Forward Next Year
CANCER
Gene Studies Reveal Cancer's Secrets
Gene Screen May Predict Colon Cancer's Return
Supplements Might Reduce Breast Cancer Risk
CAREGIVING
Few Hospitals Embracing Electronic Health Record Systems
Preventing Shaken Baby Syndrome
Diabetes Epidemic Now Poses Challenges for Nursing Homes
CIRCULATORY SYSTEM
An Apple a Day May Help Keep Heart Disease Away
Bye, Bye Back Fat?
Potassium-Rich Foods May Cut Stroke, Heart Disease Risk
COSMETIC
With Psoriasis, the Internet May Offer Hope
What to Do If You Have Unsightly Veins
Mouse Study Finds Molecule That Tells Hair to Grow
DENTAL, ORAL
Gum Disease Might Boost Cancer Risk
Gum Disease May Reactivate AIDS Virus
Health Tip: At Risk for Gingivitis
DIABETES
Poor Blood Sugar Control After Heart Surgery Impacts Outcomes
Coffee, Tea Might Stave Off Diabetes
Boosting Vitamin D Can Do a Heart Good
DIET, NUTRITION
Common Antioxidant Might Slow Parkinson's
The Food Irradiation Story
The 3LS Wellness Program for Reversing Chronic Symptoms and Creating Lasting Health
DISABILITIES
Could Your Cell Phone Help Shield You From Alzheimer's?
Review Finds Marijuana May Help MS Patients
ENVIRONMENTAL HEALTH
Where You Live May Affect Your Cancer Diagnosis
FDA Faulted for Stance on Chemical in Plastics
Old-Growth Forests Dying Off in U.S. West
EYE CARE, VISION
Guard Kids' Eyes Against Long-Term Sun Damage
When Corks Fly, Watch the Eyes
'Blind' Man Navigates Obstacle Course Without Error
FITNESS
Walk Long, Slow and Often to Help the Heart
Exercise Extends Life of Kidney Patients
Marathoners Go the Distance on Heart Health
GASTROINTESTINAL PROBLEMS
Gum Chewing May Speed Colon Surgery Recovery
Bowel Prep Harder on Women Than Men
Intestinal Bacteria Trigger Immune Response
GENERAL HEALTH
Hand-Washing Habits Still Need Improvement: Survey Says
The Yearly Flu Shot Debate
Lose Weight, Sleep Apnea May Improve
HEAD & NECK
Many Children Will Outgrow Headaches
Zen May Thicken Brain, Thwart Pain
Ski Helmets Encouraged for All
HEALTH & TECHNOLOGY
E-Mailing Your Way to Healthier Habits
Study Suggests Link Between Cell Phones and Brain Tumors
Combating Myths About Seasonal Allergies
HEARING
Summer Sounds Can Lead to Hearing Loss
Noise Hurts Men's Hearing More, Study Shows
HEART & CARDIOVASCULAR
Arteries Age Twice as Fast in Smokers
Fewer Heart Attacks After England Goes Smoke-Free
Vigorous Exercise Cuts Stroke Risk for Men, Not Women
INFECTIOUS DISEASE
Swine Flu Now Reported in All 50 States
Poor Restroom Cleaning Causes Cruise-Ship Sickness
Swine Flu Closes Three Schools in NYC
INFERTILITY
Obesity May Affect Fertility in Young Womene
KID'S HEALTH
Bullying Seems to Affect Kids Years Later
Family Medicine Cabinet Top Source Of Kid's Poisonings
Babies Cared For In Others Homes Might Become Heavy Toddlers
MEN'S HEALTH
Vigorous Exercise Cuts Stroke Risk for Men, Not Women
Noise Hurts Men's Hearing More, Study Shows
Varicose Veins May Mask Larger Problem
MENTAL HEALTH
How to Attack Holiday Stress Head-On
Reminiscing Helps Build Emotional Strength
Using the Mind to Heal the Heart
PAIN
'Cell Phone Elbow' -- A New Ill for the Wired Age
Tai Chi May Help Ease Fibromyalgia
Alleviating Rheumatoid Arthritis
PHYSICAL THERAPY
PREGNANCY
Expectant Mom's Exercise Keeps Newborn's Birth Weight Down
Sleeping Could Help Women Lose The Baby Fat
Woman in America Are Delaying Motherhood, Study Says
SENIORS
Protein Deposits May Show Up Before Memory Problems Occur, Study Says
Exercise Benefits Even the Oldest Old
Seniors Who Volunteer May Live Longer
SEXUAL HEALTH
SLEEP DISORDERS
Meditation May Help Put Primary Insomnia to Bed
Exercising Throat Muscles May Relieve Sleep Apnea
Better Sleep, Grades Seem to Go Up
WOMEN'S HEALTH
Heart Defects in Newborns Linked to Antidepressants
Iodine in Prenatal Vitamins Varies Widely
Woman in America Are Delaying Motherhood, Study Says
Add your Article

Exercise May Blunt Salt's Effect on Hypertension

Physical activity may diminish the negative impact of a high-salt diet on blood pressure, a new study suggests.

Researchers found that the more people exercise, the less their blood pressure will rise in response to a high-salt diet.

"For those with low physical activity, their blood pressure will increase more if they increase their sodium intake," said study co-author Dr. Jiang He, chair of the department of epidemiology at the Tulane University School of Public Health and Tropical Medicine in New Orleans.

"It's a little bit of a surprise," He added. "But this is the first study to look at this particular association between physical activity and salt sensitivity and blood pressure. But after thinking it over it makes sense, because we already know that physical activity will reduce blood pressure."

He and his colleagues are slated to present their findings Wednesday at the American Heart Association's meeting on nutrition, physical activity and cardiovascular disease, held in Atlanta.

High blood pressure, or hypertension, is a leading cause of stroke. Because of salt's association with high blood pressure, the American Heart Association recommends consuming less than 1,500 milligrams (mg) of sodium per day.

To explore a potential association between exercise and the hypertensive role of dietary salt, the authors focused on roughly 1,900 men and women (average age 38) living in a rural region in northern China. None took blood pressure medication during the study.

For one week all of the participants consumed 3,000 mg of sodium a day in their diet; for another week, they were placed on a high-sodium diet -- 18,000 mg per day.

Nine blood pressure readings were taken each week, and questionnaires were completed to assess routine levels of physical activity, ranging from "very active" to "quite sedentary."

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.

"Even if we don't understand the mechanism of how it works, we definitely do know that people who exercise regularly have healthier blood vessels," she noted. "The blood vessels are like a muscle. And if you engage in cardiovascular activity, they are more pliable and respond better to changes in blood volume and blood pressure."

Why this is so merits exploration, Sandon said. "One explanation might be that people who exercise more lose more salt through their sweat," she said. "Or it could be that activity sends a different kind of physiological message to the body to excrete sodium. Or it could be that it triggers a mechanism that tells the blood vessels to relax.

"To understand which it is will take further study," she added.

More information

For more on high blood pressure, visit the U.S. National Heart, Lung, and Blood Institute.

SOURCES: Jiang He, M.D., Ph.D., professor and chair, department of epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans; Lona Sandon, R.D., assistant professor of clinical nutrition, University of Texas Southwestern Medical Center at Dallas; American Heart Association, news release, March 23, 2011