Thursday, June 29, 2006

Non-diabetics should have HBA1C checked

When your blood sugar level rises too high, sugar sticks to cells. Once on a cell, sugar cannot be removed and is converted to a poison called sorbitol that destroys the cell to damage arteries and cause heart attacks. HemoglobinA1C (HBA1C) measures how much sugar is attached to cell membranes. A study in the Archives of Internal Medicine (Volume 16, 2005) shows that an HBA1C level below 4.6 percent means you are at very low risk for a heart attack. However, each one-percent increase raises the risk for a heart attack nearly 2.5 times. So people who have HBA1Cs above 4.6 are at increased risk for heart attacks, even if they are not diabetic.

More than 40 percent of Americans die of heart attacks and other blood vessel damaging diseases and 35 percent ultimately become diabetic. That means that all people who have HBA1Cs above 5 should consider losing excess weight by eating less and exercising more, avoiding smoking, and going on a diet that limits refined carbohydrates (foods made from flour or with added sugars), saturated fats (meat and chicken) and partially hydrogenated oils. If your HBA1C is above 6, your doctor may prescribe diabetic medications, even if he or she does not call you as a diabetic. See my report on insulin resistance

Wednesday, June 28, 2006

Are cell phones safe?

Researchers at the Swedish National Institute for Working Life reported that people who use cell phones for more than an hour a day for ten years are at significantly increased risk for brain cancers (International Archives of Occupational and Environmental Health, April, 2006). This study disagrees with the Dutch Health Council study and a British survey, both released this year, that failed to show increased any risk. Most studies so far have failed to show an association between cell phones and brain tumors.

Cell phones emit low dose microwaves that do not cause cancer because unlike X rays, they are not strong enough to break bonds that hold molecules together. The only way that microwaves can cause cell damage is by producing heat. A study in the British journal, Nature (May 25, 2001) showed that microwaves cause roundworms to release heat shock proteins that are a sign of tissue injury.

Nobody is concerned with the energy generated by electromagnetic waves that come into your cell phone. The concern is the energy necessary to send a signal from your phone to the tower many miles away. This 800 to 900 MHz range radio frequency comes almost exclusively from the antenna on the phone and not from the phone itself. Since the issue is not settled, it would be wise to keep the antenna at least two inches away from your skin, preferably with a wired or wireless earpiece. Sound waves in an earpiece have never been implicated in any type of damage.

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Monday, June 26, 2006

Will oxygenated water make me a better athlete?

Have you seen ads for oxygenated water, claiming to cure tiredness, improve memory, help you to exercise longer and make you a better athlete? A study from Austria shows that oxygenated water offers none of these benefits for humans (International Journal of Sports Medicine, Volume 27, 2006).

When you exercise as hard as you can, you gasp for breath because you cannot meet your needs for oxygen, no matter how hard or fast you breathe. Lack of oxygen prevents you from breaking down lactic acid so it accumulates in your muscles and blood, and you develop severe shortness of breath. Researchers analyzed the effects of drinking oxygenated water daily for two weeks on lung function and clearance of lactic acid from the bloodstream during exhausting exercise. During both exercise and rest, there was no difference between people who drank oxygenated water and those who drank ordinary water as a placebo.

Oxygenated water would be helpful to fish because they have gills whose main function is to extract oxygen from water. Since you don’t have gills, extra oxygen in water is useless to you. Lungs are the only organ humans have to provide oxygen to the bloodstream, extracting it from the air you breathe. Water is not broken down into hydrogen and oxygen in your digestive tract; it is absorbed, used and excreted as water. Since you have no mechanism for moving extra oxygen from water into your bloodstream, oxygenated water cannot possibly help you with exercise or anything else. I recommend that you save your money.

Friday, June 23, 2006

What would cause high blood pressure in a child?

Unlike high blood pressure in adults, doctors can almost always find the cause of hypertension in a child: kidney disease, blocked blood vessels, hormone abnormalities, pinching of the main blood vessels, or obesity. Many children with untreated high blood pressure have evidence of heart damage called left ventricular hypertrophy. The incidence of high blood pressure in children is increasing, probably because of the increased incidence of obesity (American Family Physician, Volume 73, 2006).

Whatever the cause, your child must learn how to control weight by exercising more and taking in fewer calories by limiting foods made with refined carbohydrates, saturated fats or partially hydrogenated oils. He or she will certainly need medication, at least until blood pressure is reduced or a cause is found. The drugs with the fewest side effects are ACE-inhibitors and angiotensin receptor blockers.

Thursday, June 22, 2006

What's the best cycling cadence?

Experienced bicycle riders know that fatigue comes from how hard you press on the pedals, not how fast you turn them. Novice racers may try to ride with maximum force on the pedals, but they quickly exhaust themselves and often can't even finish the race.

Cycling is a power sport. The number of times you spin your bicycle pedals in a minute is called your cadence, and your power is the product of the force that your feet apply to the pedals time your cadence. A study from Toledo, Spain shows that spinning the pedals too fast slows you down (Medicine and Science in Sports and Exercise, May 2006). Most bicycle riders do best when they chose gears that allow them to pedal at a cadence of 80 to 90.

You want to pedal as fast as you can with the greatest force you can maintain on your pedals, but if you spin too fast, your brain cannot coordinate your muscles so you lose efficiency. Try to choose gears that allow you to spin as fast as you can and still feel some pressure on your pedals. If you have to push on your pedals so hard that your body moves from side to side, you need to reduce the gear ratio and pedal faster. If you are spinning faster than 100 times a minute, you are probably losing coordination. Bicycle computers that show your cadence are available in bike shops and online bicycle catalogs.

When you are going out on a long ride, try to keep a comfortable fast cadence. However, if you are going to sprint or race for less than 30 minutes, you will ride faster by putting more pressure than usual on you pedals, which will slow your cadence by about 10 percent. You can also use this technique to pick up the pace when you want to catch up with another rider.

Wednesday, June 21, 2006

Does heart size affect endurance?

What laboratory test is the best predictor of finishing times for a running race of 100 kilometers (62 miles), or more than twice the distance of a marathon)? A study from Yokohama, Japan suggests that it is an echocardiogram to measure the size of your left ventricular heart chamber (British Journal of Sports Medicine, Volume 40, 2006), which determines how much blood your heart can pump with each beat. This would be expected to predict how fast you can run for short distances in which you have to move so fast that the limiting factor is lack of oxygen. This study is surprising because most athletes believe that the major limiting factor for running very long distances is the amount of fuel you can store in your muscles.

Now we know that the limiting factors for ultra- endurance competitions are similar to those of shorter distances: the time it takes to move oxygen from blood in your lungs to your muscles. This is determined by how much blood your heart can pump and how much oxygen your blood can carry. Since 98 percent of the oxygen in your blood is carried by the hemoglobin in your red blood cells, the higher your red blood count, the more oxygen you can circulate. However, a more important factor is how rapidly your heart can pump blood to your muscles, and this is determined by the strength of your heart muscle. The longer and harder you train by running, the stronger your heart, and that’s what a thicker left ventricle means. The runners who ran the most miles in training had the strongest hearts and the best finishing times. So if you want to compete in any sport requiring extremes of endurance, you have to spend a lot of time training and you also need to exercise very intensely once or twice a week to strengthen your heart.

Monday, June 19, 2006

Is loss of strength with age inevitable?

The older you become, the more you need to exercise. Researchers at Slippery Rock University of Pennsylvania measured grip strength in older men at baseline and an average of seven years later (Aging Male, September-December 2005). The men squeezed a machine that measured the force that they could exert. They lost 20 percent of their grip strength in seven years. The older they were, the more they lost. Those who lost the most height or weight, those on calcium channel blockers for high blood pressure, and those who took in the most caffeine had greater losses of strength. Loss of height is linked to osteoporosis, which is associated with loss of muscle. High blood pressure and unintentional weight loss indicate other health problems. No explanation was offered for the association of caffeine with loss of muscle strength.

These results are expected. Muscles are made of millions of individual muscle fibers. A single nerve enervates each fiber. With aging, a person loses nerve fibers that cause loss of each connected muscle fiber. However, you can continue to build strength in the remaining muscle fibers into your 90's and beyond. Perhaps all people over 50 should get a stress electrocardiogram as a screening test to see if exercise is likely to harm them. If they pass the test, they should start or continue an exercise program that includes some form of strength training such as lifting weights or using strength-training machines.

Sunday, June 18, 2006

I'm not a diabetic; why did my doctor do an HBA1C test?

When your blood sugar level rises too high, sugar sticks to cells. Once on a cell, sugar cannot be removed and is converted to a poison called sorbitol that destroys the cell to damage arteries and cause heart attacks. HemoglobinA1C (HBA1C) measures how much sugar is attached to cell membranes. A study in the Archives of Internal Medicine (Volume 16, 2005) shows that an HBA1C level below 4.6 percent means you are at very low risk for a heart attack. However, each one-percent increase raises the risk for a heart attack nearly 2.5 times. So people who have HBA1Cs above 4.6 are at increased risk for heart attacks, even if they are not diabetic.

More than 40 percent of Americans die of heart attacks and other blood vessel damaging diseases and 35 percent ultimately become diabetic. That means that all people who have HBA1Cs above 5 should consider losing excess weight by eating less and exercising more, avoiding smoking, and going on a diet that limits refined carbohydrates (foods made from flour or with added sugars), saturated fats (meat and chicken) and partially hydrogenated oils. If your HBA1C is above 6, your doctor may prescribe diabetic medications, even if he or she does not call you as a diabetic. See my report on insulin resistance

Saturday, June 17, 2006

What would cause a leg clot in an otherwise healthy person?

Leg clots occur without warning with sudden pain and swelling in a leg muscle, usually the calf. This is a particularly dangerous condition because the clot can break lose from the veins in the leg, travel to the lungs and block blood flow to kill a person. In a report in the British medical journal, Lancet (April 1, 2006), doctors at the London School of Hygiene and Tropical Medicine showed that infections may cause sudden clotting in the leg muscles called Deep Vein Thrombosis. They showed a 20 percent increase in infections, particularly urinary and respiratory, one to two weeks before a person develops clots. This report supports the current theory of inflammation causing heart attacks, strokes, and clotting. Your immunity is good because it is supposed to kill germs when they enter your body. However, if your immunity keeps on being active, it attacks your own body to damage arteries and other tissues.

People at the highest risk for clots are those who are sedentary for a long time, such as in long distance plane flights, and those who suffer cancers. Since infections are common and deep vein clots are not, you should not worry about clots every time you get an infection. However, if after a urinary or respiratory infection, you suffer sudden pain in a leg without any other explanation, check with a doctor immediately to rule out a clot.

Monday, June 12, 2006

Can I increase the number of good bacteria in my intestines?

Normal intestinal bacteria are so numerous that they make up approximately 95 percent of the total number of cells in the human body. They help prevent bad bacteria from infecting you, and may help prevent intestinal diseases such as ulcerative colitis, Crohn's disease and cancer. When you eat, enzymes from your intestines, stomach, liver and pancreas break down your food into its building blocks that can be absorbed into your bloodstream. Carbohydrates are broken down into sugars; proteins into amino acids; and fats into glycerol, fatty acids and monoglycerides. However, many foods contain undigestible starches that cannot be broken down into sugars, so they cannot be absorbed in the upper intestinal tract. When they reach the colon, the "good" bacteria ferment these undigestible starches to form other chemicals including short chain fatty acids that protect your intestinal lining from irritation and cancer, and are absorbed into your bloodstream to lower cholesterol and prevent heart tacks. These same "good" bacteria, such a lactobacillus, are used to ferment and preserve some foods made from milk or plants. So eating yogurt may help you maintain or increase the number of good bacteria you have in your gut. Not all yogurt contains live bacteria; read the label to make sure yours is "active."

Friday, June 09, 2006

Fatigue or heatstroke? Know when to stop exercising

After you have played a long tennis match on a hot summer day, you feel weaker and less accurate with your shots. The fatigue, muscle weakness, tired aching feeling and decreased coordination that you get in any sport lasting several hours is caused by low levels of fluids, salt or calories. There are no early warning signals. By the time you feel hungry, you have already run low on calories and are ready to crash. By the time you feel thirsty, you are already severely dehydrated and feel weak and tired. By the time you are low on salt, you already have tired, aching or burning muscles; feel weak, tired and dizzy; and may already have muscle cramps.

The primary limiting factor in sports that require great endurance is the time it takes for your heart to pump oxygen in your bloodstream from your lungs into your muscles. A study from the University of Connecticut (Medicine and Science in Sports and Exercise, May, 2006) shows that with dehydration, your heart beats with far less force so it pumps far less blood with each beat, and is unable to bring as much oxygen to your muscles.

You can't depend on thirst to tell you when you lack fluids. Certain brain cells called osmoreceptors tell you when you are thirty, but only after the salt concentration of your blood has risen considerably. When you exercise, you sweat. Sweat contains far more water than salt in comparison to blood. So you lose far more water than salt during exercise and blood levels of salt rise. By the time that a your blood salt concentration is high enough to trip off the osmoreceptors, you are severely dehydrated and it is too late for you to be able to drink enough during exercise to catch up with your water deficit. On the other hand, if you take salt with fluids, then your blood salt levels rise faster and tell you that you are thirsty earlier.

There are other reasons that you should take salt with fluids during prolonged exercise. First, it helps prevent muscle cramps. Remember, during exercise you lose salt and water. If you are replacing only water, you can eventually take in so much water that your salt levels drop to cause muscle cramps. Second, even though salt is a mild diuretic at rest, during exercise it helps your body to retain water. So when you are going to exercise for more than a couple hours, particularly in hot weather, drink small amounts frequently and eat salted foods such as peanuts. Always stop if you feel sick, have chills, headache, severe muscle burning or aching, dizziness, or blurred vision. Seek help if your symptoms do not subside in a few minutes; you could be headed for heat stroke that can kill you.

Thursday, June 08, 2006

Are there any drugs to make athletes stronger that are not banned?

Some athletes take estrogen blockers and human chorionic gonadotropin (Journal of Clinical Endocrinology & Metabolism, Volume 91, 2006), which have not been banned by sports authorities such as the Olympic committee. Estrogen blockers such as Tamoxifen, Arimedex, Aromasin, and Femara are used to treat women with, or at high risk, for breast cancer. Evidently lowering the female hormone, estrogen, may act the same way as raising the male hormone, testosterone, to help athletes recover faster from hard workouts. Human chorionic gonadotropins are hormones that are produced in very large amounts by a woman's body when she is pregnant. These hormones appear to promote cells growth, which includes muscle tissue.

Both male and female athletes can experience strength gains from these hormones or anti-hormones. Since nobody really knows all the side effects that occur when healthy athletes take them, the athletes may be risking their lives.

Saturday, June 03, 2006

How does weight loss affect your heart?

A study from Turkey shows that the heart beats with greater strength when a person loses weight (Heart Vessels, March 2006). The obese patients in the study received echocardiograms to predict their risk for heart failure by measuring their left ventricular function. After they lost at least ten percent of their total body weight, the strength of the contractions of their hearts increased significantly. This study shows that weight loss should be part of the treatment for heart failure if the person is overweight. It also explains why being overweight makes you tired and short of breath, because your heart has to work much harder to push blood through blood vessels blocked by fat. Losing excess weight improves heart function and also helps to prevent diabetes, heart attacks, strokes, kidney damage and even certain cancers.

Best diet for heart health and weight loss

Friday, June 02, 2006

How can I prevent wrinkles?

Unfortunately, there may not be much you can do; a study from Denmark shows that skin wrinkling and aging are influenced heavily by genetic factors (Age and Aging, January 2006). However, this doesn’t mean that you can smoke or spend many hours in the sun, two behaviors that are known to increase wrinkling. The authors studied twins to show that skin aging is associated equally between genetic and environmental factors. They also found that looking older with severely wrinkled skin is associated with dying earlier. You increase your chances of having aged, wrinkled skin by smoking, exposing your skin frequently to sunlight or being very thin.

Read more about why skin creams may do more harm than good.

Thursday, June 01, 2006

Does extra protein build muscles?

Many body builders and weight lifters are overly concerned about what they eat and what food supplements they take. If you want to grow larger and stronger muscles, it helps to understand how food can help your training program. Just exercising does not grow large muscles. If volume of exercise made you strong, marathon runners would have the largest muscles. The only stimulus to make muscles larger and stronger is to stretch them while they contract against resistance. When you lift a heavy weight, your muscles start to stretch before they start to contract. This tears the muscle and causes soreness on the next day. If you rest and let the muscle heal, it will be stronger than before you stretched it. You improve by taking hard workouts so your muscles can grow and heal while you recover on your easy days.

Anything that helps you recover faster from a hard workout will allow you to do more work to make you stronger. Scientists have known for years that you recover faster by eating immediately after you finish your hard workout. Now we know that eating extra protein helps you recover even faster. Muscles are made primarily from protein building blocks called amino acids. Muscles heal from a hard workout when amino acids and other nutrients travel from your bloodstream into the muscles. Eating any food, particularly foods with plenty of protein, immediately after you finish your workout helps your muscles heal faster so you can do more work. The sooner you eat protein after you finish your hard workout, the quicker you will recover.

However, you don't need to take expensive supplements; ordinary foods provide high-quality protein and taste better. Remember, your body cannot store extra protein. If you don't need all of the protein you have eaten, it is broken down into ammonia and organic acids, which are used for energy. Any excess is stored as fat.