Friday, August 29, 2008

More exercise, less high blood pressure

People who continue to exercise throughout their lifetimes are far less likely to develop high blood pressure and the more they exercise, the less likely they are to develop high blood pressure (Journal of Hypertension, June 2008). In various studies, up to 91 percent of the North American population suffers from high blood pressure which puts them at markedly increased risk for strokes, heart attacks, kidney damage and arteriosclerosis. Virtually all scientists agree that this frightening incidence of high blood pressure is caused by lifestyle, and the major lifestyle factors are lack of exercise, obesity, and eating too many calories, refined carbohydrates and saturated fats.

For some people, but not all, increased intake of salt also contributes to high blood pressure. However, if you exercise, you need to take in extra salt since salt is the only mineral that you lose in large amounts through sweating. Low salt levels can cause muscle damage, fatigue and depression. Salt deficiency can also raise high blood pressure because it causes your kidneys to produce large amounts of renin and your adrenal glands to make more aldosterone. These hormones constrict arteries to raise blood pressure.

Monday, August 25, 2008

Measure Abdominal Fat, Not Just Weight

Researchers at the University of Michigan report that not all people who are fat are at high risk for heart attacks (Archives of Internal Medicine, August, 2008). They showed that 51 percent of overweight adults (36 million Americans) have normal blood pressure, cholesterol and blood sugar, while 25 percent of normal- weight Americans (16 million) have high levels of at least two of these tests. The media picked up this study with headlines such as "Better to Be Fat and Fit Than Skinny and Unfit" (New York Times, August 19, 2008).

However, the entire study is flawed. The authors measured overweight, not abdominal obesity. If you just compare weight to height to define obesity, more than 50 percent of professional football players would be obese, and they are not. I am sure that the study would show the far more harmful effects if the authors had measured abdominal obesity rather than just weight. Storing fat primarily in your belly can predict premature death. It means that a person's insulin levels are very high and high insulin levels mean that your body is not responding to insulin so you are at increased risk for a heart attack, stroke, kidney damage, arteriosclerosis and all the other harmful side effects of diabetes.

Other studies do show that it is better to be fat and fit than out-of-shape at any weight. Steven N. Blair of the University of South Carolina showed that adults over 60 who had higher levels of fitness lived longer than unfit adults, independent of how fat they were (JAMA, December 5, 2007). He showed that fat people who were able to run on a treadmill longer than unfit, fat people had better blood tests and fewer heart attacks and deaths.

How should these studies affect you? If you are overweight, you increase your risk for heart attacks, strokes, cancers and premature death. If you store large amounts of fat primarily in your belly, you are at such great risk for premature death that you should check with your doctor and probably get a thallium stress test to see if your coronary arteries are already blocked. If they are not blocked, start a supervised exercise program and diet to lose weight and become fit. If your coronary arteries are already blocked, you will need immediate counseling about future treatment.
Vacation photos

Friday, August 22, 2008

Saturated fat risks cancelled by exercise

The Masai of Kenya and Tanzania eat the same type of high animal-fat diet as North Americans, but they have a very low incidence of heart attacks. In spite of the large amount of saturated fats in their diets, they have lower body weights, waist measurements, blood pressures and cholesterol levels (British Journal of Sports Medicine, July 2008). This is explained by the fact that the average Masai burns 4,000 kilocalories a day, which is roughly equal to walking 12 miles every day (this number includes the amount you burn for normal daily activities such as breathing and sleeping).

Saturated fat is the dominant fat in meat, chicken and whole milk dairy products. It raises cholesterol only when a person takes in more calories than he burns. A high-meat diet does not cause heart attacks in people who get a lot of exercise. Saturated fats are broken down by your body into two-carbon units. If you are getting too many calories, your liver converts these two-carbon units into cholesterol. If you are not getting enough calories, your body burns these units for energy.

When you take in more calories than your body needs, you store the excess as fat. Full fat cells release cytokines into your bloodstream, and they turn on your immunity. Your immunity is good because it protects you from infection, but if it stays overactive, it starts to destroy your body including your heart and blood vessels. The bottom line: if you eat much saturated fat, be sure to get plenty of exercise.
New photo of us