Stress, activity, age and diet all affect your blood pressure. Eating too much salt during the day can increase your blood pressure significantly. For those with already-diagnosed hypertension, this knowledge is particularly important. High sodium intake causes water retention, which acutely raises blood pressure. Luckily, you can take steps to control your sodium intake, which can greatly benefit your blood pressure and cardiovascular system.
Influences
Blood pressure is measured according to millimeters of mercury, abbreviated mmHg, which is a measurement of force. A normal and healthy blood pressure should be kept under 120/80 mmHg, accoring to the American Heart Association. Between 120/80 mmHg and 140/90 mmHg is pre-hypertensive. If your blood pressure is 140/90 mmHg or greater, it is considered hypertensive.
Your blood pressure is a product of cardiac output and total peripheral resistance. Cardiac output is the amount of blood your heart pumps out each minute. Total peripheral resistance refers to the resistance against blood flow. For example, if veins are constricted, there is force working against blood flow that will raise the amount of force blood must produce to flow against it.
Sodium and Blood Pressure
Sodium is an electrolyte, a positive ion. In order to balance out your electrolytes, your body must also hold onto fluid. When you eat large amounts of salt, your brain signals your body to hold onto fluid. It also emits the thirst sensation so that you take in more water as well. Water retention increases the volume of your blood. This increases cardiac output and resistance. Your heart must work harder to pump more blood, and it must also work against the added resistance that the fluid places on the cardiovascular system.
Cutting Down on Salt
A study conducted by the Harvard Medical School in 2001 sought out to understand how effective cutting down on salt can be on blood pressure. This study took 412 participants and placed them on a regular-salt diet of 3,300 mg of sodium per day, a moderate-salt diet of 2,400 mg per day and a low-salt diet of 1,500 mg per day. When dieters cut down salt intake to 1,500 mg per day, blood pressure dropped by 8.3 mmHg. This is significant because it could make the difference between hypertension and a healthy blood pressure.
Recommendations
One of the most effective ways to cut down on salt is to follow the U.S. Department of Agriculture's DASH diet. This diet restricts salt intake to 2,300 mg but suggests lowering salt intake to even 1,500 mg for better results. It also emphasizes a restriction on fat and cholesterol intake. Total fat should be less than 27 percent of calories, and saturated fat should be no more than 6 percent of calories. Cholesterol intake should not exceed 150 mg per day. This dietary strategy has been successful for many at lowering and preventing high blood pressure.
References
- San Diego State University: Acute Cardiovascular Response to Exercise
- "Nutrition: Concepts and Controversies"; Frances Sizer and Eleanor Whitney; 2004.
- American Association of Kidney Patients; Why Does Salt Cause High Blood Pressure?
- CNN; Study: Reducing Salt Really Does Lower Blood Pressure; January 2001
- U.S. Department of Agriculture; Your Guide to Lowering Your Blood Pressure With DASH; April 2006
- U.S. Department of Agriculture; Dietary Guidelines for Americans: 2010; February 2011
