Friday, September 30, 2005

How can I increase my endurance?

It takes a lot of energy to run, cycle or ski long distances; to play three sets of tennis or a pickup game of basketball; or to walk for several hours. During intense exercise, your muscles draw sugar from your bloodstream at a rapid rate. Your liver can run out of its stored sugar and your blood sugar level can drop. You can markedly improve your performance in any of these events by eating shortly before your event begins, and by starting to eat and drink as soon as you start exercising.

The energy for your brain comes almost exclusively from the sugar in your bloodstream. When blood sugar levels drop, you feel tired and have difficulty coordinating your muscles. However, there is only enough sugar in your bloodstream to last three minutes at rest. To maintain blood sugar levels, your liver has to release sugar into your bloodstream. But there is only enough sugar in your liver to last around twelve hours at rest and far less than that when you exercise. When muscles run out of their stored sugar supply, it hurts to exercise and the muscles become difficult to control. Most people who exercise for more than an hour will improve their endurance if they start replenishing energy reserves as soon as they start to exercise.

Hunger during exercise is a very late sign of not getting enough calories. You can increase your endurance by starting to eat anything or to drink fluids that contain sugar as soon as you start to exercise. This will give you far greater endurance than waiting to take food after an hour of exercise or when you feel hungry.

Wednesday, September 28, 2005

Will taking boron help to build stronger muscles?

You should always be skeptical of articles in sports magazines about pills that make you a better athlete. There are no non-prescription pills that will grow stronger muscles. The only two types of pills that can make you stronger are hormones such as testosterone or growth hormone, and beta agonist derivatives used to treat asthma. These drugs are banned by the International Olympic Committee and are available legally only by prescription.

Several studies have shown that lack of boron weakens bones, but there is no data to show that extra boron makes bones stronger. One study from the US Department of Agriculture showed that boron pills increased blood levels of testosterone in post-menopausal women, but it is illogical to conclude from this study that boron pills make athletes stronger. Giving testosterone to athletes causes them to recover faster from exercise so they can train harder and grow larger and stronger muscles. However, the USDA study did not measure the women's strength, athletic training or muscle size. In spite of this, articles appeared in sports magazines claiming that boron pills make you stronger. If you want to grow larger and stronger muscles, don’t look for pills; lift heavier weights and then allow enough time for your muscles to recover before you lift heavy weights again.

Tuesday, September 27, 2005

Will exercising without a bra cause my breasts to sag?

Women can wear bras when they exercise if they want to, but there is no medical evidence that exercising braless will harm them or cause breasts to sag. A breast is made up of skin on the outside, fat underneath and muscles under that. Breasts are held in place by skin and small ligaments that go from the skin to muscles underneath the breasts. The intermittent stretching that occurs during exercise does not stretch out the skin or ligaments. A breast is composed mostly of fat, so when a woman starts to exercise, she loses fat from her breast as well as the rest of her body and they become smaller and may appear to sag. Sagging is determined to some degree by heredity. All women develop some sagging as they age and those with the largest breasts are the ones who are most likely to develop sagging.

Many women with small breasts prefer not to wear bras when they exercise. However, women with large breasts may need them to feel comfortable. If a woman wants to wear a bra, she should choose one that is loose enough to let her breathe comfortably, and tight enough to keep the breasts from bouncing and the bra from riding up or twisting during exercise. The bra should not have bones or wires that dig into the body, or rough seams or hooks that rub against the skin.

Monday, September 26, 2005

How can I tell which fats are healthful and which are unhealthful?

Fat is classified into saturated fats, polyunsaturated fats, and monounsaturated fats. Saturated fats appear to increase your risk for heart attacks when you take in more calories than you burn.

Monounsaturated fats are considered healthful because they form LDL cholesterol that is resistant to oxidation; plaques are formed by oxidized LDL. Good sources include olive oil and avocados.

We used to think that all polyunsaturated fats help to prevent heart attacks when they replace saturated fats, but now we have different information. Polyunsaturated fats are classified by their structures into omega-3s and omega-6s, and you need both types; these are called the essential fatty acids because you cannot make them in your body and must get them from your food.

For most of the time humans have been on earth we have eaten foods that contain omega-6's and omega-3's in a ratio of about 2:1. However, over the last 50 years in North America, the ratio has changed; it now ranges from 10:1 to 20:1. Today our diet includes huge amounts of oils that are extracted from plants and used for cooking or in prepared foods. These oils (such as corn oil, safflower oil, cottonseed oil, peanut oil, soybean oil) are primarily omega-6s. We have decreased our intake of omega-3's, found primarily in whole grains, beans and other seeds, and seafood. Eating too much omega-6 and too little omega-3 causes clots and constricts arteries to increase risk for heart attacks, increases swelling to worsen arthritis, and aggravates a skin disease called psoriasis. It may block a person’s ability to respond to insulin, causing high insulin and blood sugar levels and obesity. It increases hormone levels of insulin like growth factor-1 that causes certain cancers. To get your ratio on omega-6s to omega-3s back to a more healthful 2:1, eat seafood, whole grains, beans and other seeds, and reduce your intake of foods made with or cooked in vegetable oils.

The most unhealthful fats are the polyunsaturated oils that have been processed to form trans fats (partially hydrogenated vegetable oils); see reports #N198 and #N185.

Sunday, September 25, 2005

How can pepper cream control pain?

Pain messages are passed along nerves by a neurotransmitter called substance P. Capsaicin, the substance that makes peppers hot, blocks substance P and the resultant pain. A cream containing .025 percent capsaicin has been shown to block pain in joints, nerves and skin. It can be used to relieve the pain from a variety of causes: arthritis, surgery, various injuries, tumors, nerve damage from diabetes and so forth. Reports suggest that capsaicin cream also can control the discomfort of cluster headaches, psoriasis or itching from any cause.

Pepper creams are available over-the-counter in most drug stores. When you use pepper cream, you need to know that capsaicin is a very stable alkaloid that does not wash off your skin, even with soap. If you apply it with your fingertips and later touch your eyes, lips, or any mucous membrane or open cuts, you can get a nasty burning sensation that will last about twenty minutes. You can avoid this problem by wearing rubber gloves to apply it, or buy the pepper cream in a special roll-on applicator bottle so you don’t get it on your hands.

Saturday, September 24, 2005

I have arthritis; should I exercise?

When you have arthritis, your joints hurt you wake up, but you force yourself to get out of bed and as you keep on moving, the pain lessens. Is your body trying to tell you something when you feel better after you start to move? Many studies have shown that bed rest worsens the pain of arthritis, and a strength training program can help to control it.

Most people with arthritis think they should rest their muscles and joints, but resting is the worst thing you can do. When you move around, the cartilage in your joints acts like a shock absorber. Resting weakens cartilage and increases its likelihood to break. Resting also weakens muscles so they can’t control the joints, allowing more wobble of the joints with each movement and increasing cartilage damage.

People with arthritis should exercise, but they should not jog, run or engage in sports that cause your feet to pound on the ground, such as tennis or rope-jumping. When you hit the ground hard with each step, your foot stops suddenly and the force is transmitted up your leg to your knees and hips. This force can break cartilage. Choose an activity with smooth motions such as cycling, swimming or rowing. You can pedal a bicycle because pedaling is done in a smooth rotary motion that does not jar your joints.

People with arthritis should also lift weights because this strengthens muscles to stabilize joints, and helps to strengthen cartilage to protect it from breaking. Ideally, everyone with arthritis should have access to weight machines and be taught how to lift weights with proper form, in sets of ten, two or three times week. The combination of a smooth, continuous exercise and a supervised weight lifting can help protect you from further joint damage and reduce your pain.

If you have pain in multiple joints or sudden onset of joint pain, read more about reactive arthritis

Friday, September 23, 2005

Will vinegar help me lose weight?

Vinegar is an excellent preservative and a good household cleaner, but it is not a medicine or a weight-loss drug. Several popular books claim that vinegar prevents cancer and heart disease, lowers high blood pressure and helps you to lose weight, but here is no evidence to support any of these claims. One of the books explains that vinegar helps you to lose weight because oil and vinegar don't mix, so vinegar and your fat won't either.

Vinegar is nothing more than a mixture of 95 percent water and around 5 percent acetic acid, made from grapes, apples, rice, potatoes or other fermented plants. It is very low in calories, but the only way vinegar could possibly help you to lose weight is by causing you to eat lots of salads while you cut back on other sources of calories. Try Diana's Mix and Match Salads.

You can put vinegar in a footbath to help soften hard calluses. Because it is acidic, it prevents the growth of bacteria in a bottle and is used as a preservative to pickle a wide variety of foods. However, it has not been shown to prevent infection in humans.

Thursday, September 22, 2005

Should I exercise when I have a cold or the flu?

Most doctors allow their patients to exercise when they have a cold, as long as they don't have a fever and their muscles don't hurt when they exercise. However, it's probably better to stop exercising altogether when you have an infection. You risk injury if you exercise when your muscles hurt at rest or when you start to exercise. When muscles are damaged, they release enzymes from their cells into the bloodstream and they fill with blood from broken blood vessels. One study reported markedly increased muscle damage during relatively minor exercise during an infection, with blood tests demonstrating increases in muscle enzymes and ultrasound tests demonstrating hemorrhage into the muscles.

You also should not exercise when you have a high fever. When you exercise, your heart has to pump blood to your muscles to supply them with oxygen. It also has to pump blood from your muscles to your skin where the heat is dissipated. When you have a fever, your heart has to work extra hard to get rid of extra heat. Furthermore, some viruses that infect your nose and throat can also infect your heart muscle. The combination of the extra work and an infected heart muscle could cause irregular heart beats. You won't lose much conditioning unless you take off more than a week.

Wednesday, September 21, 2005

Why do exercisers need salt?

The key to retaining water during exercise is to take in salt to replace the salt you lose in your sweat. Until recently, many scientists did not appreciated how important salt is to retaining fluid in your body. Thirst is a late sign of dehydration. You lose water during exercise primarily through sweating, and sweat contains a far lower concentration of salt than blood. So exercisers lose far more water than salt, causing the concentration of salt in the blood to rise. A person will not feel thirsty until the concentration of salt in the blood rises high enough to trip off thirst osmoreceptors in the brain and it takes a loss of between 2 and 4 pints of fluid to do that.

You need to take salt to retain the fluid you drink while exercising. If you lose two pints of fluid, you can replace it with two pints of water if you also take salt, but if you don't take salt, it can take four pints of fluid to replace two pints of sweat because the water you drink will pass out through your kidneys. In one study, female competitive distance runners took in drinks with different concentration of salt during a four-hour run. Ninety-two percent of those who took in plain water with no additional salt developed low blood levels of salt. Taking in fluid without also taking in adequate amounts of salt dilutes the bloodstream, so that the concentration of salt in the blood is lower than that in brain cells. This causes fluid to move from the low-salt blood into the high-salt brain causing the brain to swell which can cause seizures and death. Taking in extra salt during prolonged exercise increases thirst so you drink more fluids, and prevents blood salt levels from dropping so low that you become tired, develop muscle cramps, and can even die. You can keep yourself fresh during extended exercise by eating foods with salt and drinking frequently, before you feel hungry or thirsty. Once you feel hungry or thirsty, you will find it very difficult to regain your strength. Please read the earlier post on hyponatremia.

Tuesday, September 20, 2005

Does it matter whether I get omega-3 fatty acids from plants or seafood?

By now, most people know that omega-3 fatty acids help to prevent heart attacks, and that they can get lots of omega-3 fatty acids from fish. But most people do not know that the omega-3 fatty acids in seeds such as whole grains may be even more important in maintaining your health than the omega-3 fatty acids found in fish. Virtually every plant source of omega-3's also contains vitamin E, while fish oils are low in vitamin E. All omega-3's break down very quickly when exposed to oxygen in your body, and vitamin E stabilizes them so they are more effective.

Omega-3s found in fish oils are mostly long chain fatty acids. Omega-3s in plants, particularly seeds, contain much shorter chains and are weaker than the omega-3s found in fish. However, the shorter chain omega-3s, particularly alpha-linolenic acid (ALA), found in leafy greens and seeds are converted to the long chain fatty acids in the human body. To meet your needs for short chain omega-3 fatty acids found in plants, eat lots of green leafy vegetables, and seeds such as flaxseed, whole grains, beans and nuts.

Monday, September 19, 2005

What exercise can I do after a knee injury?

If you break cartilage in your knee, avoid sports that cause further damage such as those requiring running and jumping. You can help to prevent more cartilage loss with an exercise program that strengthens the muscles that control your knee. Bones are soft. To keep them from wearing down at joints, their ends are covered with a thick white gristle called cartilage. Broken cartilage never heals. Removing broken cartilage may increase a person's chances of needing a knee replacement in the future, particularly if the exerciser continues to run and jump.

Former world-class athletes are supposed to have tough, strong bodies, but they suffer high risk for permanent knee damage, while non-competitive exercisers are at very low risk. Repeated cortisone-type injections can weaken cartilage and cause further damage. Nonsteroidal pain medications do not prevent further damage. Weak thigh muscles increase chances for further knee damage, so all people with knee damage should strengthen the muscles that control their knees using a special knee weight machine, and start a supervised program of cycling or swimming, provided that it does not hurt.

Sunday, September 18, 2005

Does stress increase your need for vitamins?

Several years ago a major drug company claimed that its vitamin pills helped to relieve stress from the "complications of everyday life" and gave their products names such as "StressTabs." The New York Attorney General forced them to stop their deceptive advertising, but many people still remember and believe this claim. There is no evidence that stress increases your needs for vitamins or that taking vitamins will help you handle stress. When you eat vitamins in pills or in your food, they go into your bloodstream and then into cells. They function by combining with other chemicals in cells called apoenzymes, to form complete enzymes that cause reactions to proceed in your body. All chemical reactions in your body require enzymes to make them go, and that is why vitamins are essential. For example, all of the B vitamins form enzymes that convert food to energy. But since enzymes only start chemical reactions and are not used up by them, they can be used over and over again and only minuscule amounts are needed from your diet.

In the 1930's, Hans Selye of McGill University in Montreal reported that the adrenal glands contain the highest concentration in the body of vitamin C. The adrenal glands make cortisol from vitamin C. When a person is under stress, the adrenal glands make tremendous amounts of cortisol and the concentration of vitamin C in them drops. However, scientists have known for more than forty years that the levels of vitamin C in the adrenal glands are still high enough to continue to produce cortisol and that giving extra vitamin C will not increase production of cortisol. So the myth that vitamins treat stress is based on a misinterpretation of one study on one vitamin, and that research did not show that taking extra vitamins prevents stress.

Saturday, September 17, 2005

How can I get rid of cellulite on my thighs?

There is no such thing as cellulite. The fat on a woman's hips and thighs is the same as the fat anywhere else. She has skin on the outside, fat in the middle and muscles and fascia underneath the fat. Tiny bands of fiber called ligaments run from the fascia, through the fat and attach on the skin. When fat is stored on the hips and thighs, it pushes the skin upwards, while the ligaments hold the skin down, causing an orange peel appearance from the little dots where each ligament attaches to the skin.

Getting rid of fat gets rid of the dimpling, but for women who store fat primarily in their hips and thighs (rather than their bellies), this can be very difficult. You can be skinny everywhere else and still have dimpled thighs. The Federal Trade Commission has filed lawsuits to prevent entrepreneurs from claiming that their products get rid of cellulite.

Friday, September 16, 2005

What can I do about side stitches ?

It took years for the medical community to finally learn what causes a side stitch. Suddenly a runner develops pain in the right upper part of the belly, just underneath the ribs in the front. With each step the pain worsens. Doctors proposed all sorts of explanations for side stitch and most were nonsense. A stitch is not caused by gas in the colon because it is not relived by passing gas. It is not caused by a liver swollen with blood during running, because the liver has a very distensible capsule and does not enlarge much during exercise. It is not caused by cramps in the belly muscles because the belly muscles are not held rigidly when you have a side stitch, and it does not hurt when you push on the belly muscles. Lack of oxygen to the diaphragm doesn't cause them because blood flow to the diaphragm is not shut off by running. They are not caused by trapped gas in the lungs because gas does not get trapped in the lungs during exercise.

The first reasonable explanation and successful treatment came from Dr. Tim Noakes. Thick fibrous bands called ligaments extend downward from your diaphragm to hold your liver in place. When you run, your liver drops at the exact time that your diaphragm goes up, stretching the ligaments and causing pain. Humans have a fixed pattern of breathing when they run. They have a two to one breathing ratio, breathing once for each two strides. Most people breathe out when the right foot strikes the ground. When you breathe out, your diaphragm goes up, and at the same time, the force of your foot strike causes your liver to go down. This stretches the ligaments that attach the liver to your diaphragm, causing pain. So the cause of a side stitch during hard running is a stretching of the ligaments that hold the liver to the diaphragm and the cure is to relieve the stretching of the ligaments.

When you get a side stitch, stop running and press your hand deep into your liver to raise it up against your diaphragm. At the same time, purse your lips and blow out against the tightly held lips as hard as you can. Pushing the liver up stops stretching the ligaments. Breathing out hard empties your lungs. Usually the pain is relieved immediately and you can resume running as soon as the pain disappears.

Thursday, September 15, 2005

What’s the best time to do stretches?

Stretching should always be done after your muscles are warmed up. Warming up raises muscle temperature to make them more pliable and resistant to injury. Resting muscle temperature is only about 97 degrees, but a slow jog around the block or any similar warm-up activity will raise muscle temperature to more than 99 degrees. Then you can do your stretches, or you can stretch after you finish your workout.

There’s no good evidence that stretching prevents injuries, but stretching that is done properly can help to make you a better athlete. Competitive athletes stretch to make muscles and tendons longer to generate a greater torque about a joint, so they can lift heavier, run faster, jump higher or throw further. Stretch no further than you can hold for a few seconds. Bouncing gives you a longer stretch, but it can tear muscles. Only competitive athletes need to stretch further than they can hold for a few seconds. Forceful stretching will give you greater flexibility than slow deliberate stretching, but it increases your chances of injuring yourself. If you're over 50, be extra careful because older muscles are less springy and more likely to tear.

Wednesday, September 14, 2005

What causes dark facial hair on a woman?

Five to ten percent of North American women have hirsutism, or excessive hair on their faces and bodies. Women have the same number of hairs on their bodies and faces as men do, but the male hormone, testosterone, makes hairs thicker, darker and longer, so they are more noticeable. Some women with heavy facial and body hair have normal amounts of testosterone and inherit this tendency. Others have a medical condition that causes their bodies to produce larger amounts of testosterone.

Women with noticeable facial hair should get blood tests for testosterone to measure male hormones made by the ovaries and DHEAS to measure male hormones produced by the adrenal glands. They should also get a sonogram of their ovaries to test for polycystic ovary syndrome (PCOS) in which the ovaries do not release eggs each month. Other PCOS symptoms include storing fat primarily in the belly, irregular periods, acne, or infertility. For more on diagnosis and treatment of PCOS see report #8124.

Tuesday, September 13, 2005

What can I do about shin pain?

Posterior shin splints occur when you damage the posterior tibial muscles in the inside back of your lower leg. Some very good bicycle racers develop painful shin splints on the front inside of the lower legs when they try to train for triathlons. In a triathlon, you compete in three events: running, cycling and swimming. They have to stop running until they can run without feeling pain.

Bicycle riding develops very strong upper leg muscles because you pedal with your knees and hips. It does not stress your lower leg muscles much. Running stresses mostly your lower leg muscles. When you run, you land on your heels and raise yourself up on your toes with the calf muscles in the back and the posterior tibial muscles on the inside back part of your lower leg. So your upper leg muscles can handle the stress of running very easily, but your lower leg muscles are not strong enough and you tore them.

Once a runner develops shin splints, he or she has to stop running to let the muscle and tendon injury heal. A bicycle rider has to go back to the bike. When he can run without hurting, he should try to run on one day and cycle on the next and stop running immediately when he feels pain in his lower leg. When he can run for 30 minutes without feeling pain, he can start training again by adding fast runs. In the future, he should not run very fast more often than every other day or twice a week.

Can I exercise after donating blood?

A healthy person should be able to recover completely from donating blood in eight weeks, but you may lose some of your ability to train for a few days. Following a donation of one pint, blood volume is reduced by around ten percent and returns to normal in 48 hours. So, for two days after donating, you should drink lots of fluids and probably exercise at a reduced intensity or not at all. Donating blood markedly reduces competitive performance for three to four weeks as it takes that long for blood hemoglobin levels to return to normal.

You should not donate blood more often than every eight weeks because it takes that long to replace lost nutrients. If you donate blood frequently you need to make sure to replace the B vitamins and iron that you lose with the blood. You can meet your needs for iron by eating meat, fish or chicken or by taking iron supplements; and you can meet your needs for the B vitamins with whole grains and diary products. Donating blood at least four times a year may help to prevent heart attacks by lowering blood cholesterol levels significantly and reducing iron levels. Iron in the bloodstream converts the bad LDL cholesterol to oxidized LDL which can form plaques in arteries.

Monday, September 12, 2005

Do you burn more calories in hot or cold weather?

You burn fewer calories when you exercise in cold weather than you do when it's hot. The hotter it is, the more extra work your heart has to do to prevent you from overheating. More than 70 percent of the energy produced by your muscles during exercise is lost as heat. So the harder you exercise, the hotter your muscles become. In hot weather, not only must your heart pump extra blood to bring oxygen to your muscles, it must also pump hot blood from your heated muscles to your skin where heat can be dissipated.

On the other hand, in cold weather, your heart only has to pump blood to your muscles and very little extra blood to your skin to dissipate heat. Your muscles produce so much heat during exercise that your body does not need to produce more heat to keep you warm. So your heart works harder and you burn more calories in hot weather. This information should not discourage you from exercising when it’s cold, because staying in shape is a year-round proposition. However, it may help to explain why so many people find the pounds creeping on in the wintertime, even when they stay active.

Sunday, September 11, 2005

Should you train or rest before a major race?

The best way to train a couple of days before an important race or a marathon is to stop training altogether. How long you can exercise a muscle depends on how much sugar you can store in that muscle before you start to exercise. Dr. Dave Costill of Ball State University asked one group of highly- trained runners to jog at a slow pace on the two days prior to measuring their muscle sugars and another group to not jog at all. The runners who didn't jog stored the most sugar.

Studies on bicycle racers show that their muscles will load maximally with sugar when they take a very hard workout four days prior to racing and then ride easily for the next three days. However, running three or four days before a marathon will decrease the amount of sugar that muscles can store, presumably because hard running damages muscles and interferes with their ability to store sugar.

There is no evidence that a hard workout in the week before a race will help a runner during that race. Hard training tears down muscles and it take several days for the muscles to heal sufficiently to improve performance. Run at a slow pace on the fifth, fourth and third day before your event, and don’t run at all on the last two days.

Thursday, September 08, 2005

How does fatigue affect your strength?

It's the ninth inning, your team leads by one run and your starting pitcher, who usually has very good control, has just walked the first two batters. That means it's probably time to bring in a relief pitcher. The old one has pitched nine innings and prolonged exercise has weakened his muscles. Fatigue has already reduced the pitcher's power and accuracy. The same principle applies to all team sports. Teams that substitute freely early in a game have fresher players late in a game. That's why the best professional and college teams usually have the largest rosters.

There's a physiologic reason why tiredness weakens muscles. Muscles are made up of thousands of fibers. Each fiber stores sugar. and when it runs out of its stored sugar, it cannot contract effectively. So, as you tire, your muscles have fewer fibers to contract and you become weaker and less coordinated. That means that a pitcher who is warmed up and fresh will have more active fibers in his muscles and be able to throw more accurately and faster than when he is tired. A fresh football player can kick further and more accurately than when he is tired. The same principle applies to boxers and wrestlers who are weaker towards the end of bouts. You lose both accuracy and strength as you become tired. So, when you compete in a sport that requires endurance and you cannot use a substitute, take it easy early in your competition.

Wednesday, September 07, 2005

Is it normal for my muscles to feel sore for several days after a workout?

Yes; after you’ve exercised vigorously, your muscles may feel fine, but they usually feel sore the next morning. Delayed-onset muscle soreness is caused by damage to muscle fibers. A study from the University of Zurich helps to explain why it takes days for muscles to recover from hard exercise (European Journal of Nutrition, June 2004). Muscles store sugar as glycogen in their fibers for energy, and this study shows that for the first few hours after hard exercise, muscles continue to lose glycogen. Since recovery depends on refilling muscles with stored glycogen as soon as possible after hard exercise, athletes should eat a high-carbohydrate, high protein meal as soon as possible after a hard workout and then take easy workouts for as many days as it takes for the soreness to go away. Taking another hard workout while the muscles feel sore increases risk for injures, so you should follow your hard workouts with easy days or days off until the soreness goes away.

Are barbequed foods dangerous?

Eating any type of browned foods may contribute to heart attacks, strokes or nerve damage. Diabetics suffer a very high incidence of nerve, artery and kidney damage because high blood sugar levels cause sugar to attach to protein, forming advanced glycation products. The frightening news is that browning foods also forms advanced glycation products, and eating them raises blood and tissue levels and increases nerve damage.

Cooking without water causes sugars to bind to proteins, while cooking with water prevents this process. Baking, roasting and broiling cause the advanced glycation products to form, while boiling and steaming do not. See report #1220. This is just one more reason why you should base your meals on fruits, vegetables, whole grains and beans -- fresh, steamed or cooked with water. Make grilled and browned foods a minor part of your diet.

Tuesday, September 06, 2005

How can I keep from losing brain power as I get older?

If you feel you are losing your ability to reason or think clearly, or if you suffer mood disorders such as depression, ask your doctor to do blood tests for homocysteine, folic acid, pyridoxine and vitamin B12. If these tests are normal, you should get tests for thyroid function, cholesterol and other causes of arterial damage. People with high levels of homocysteine levels or low levels of B12, folic acid or pyridoxine levels should eat plenty of whole grains and leafy green vegetables for folic acid and pyridoxine, and 1000 micrograms of B12 in a pill each day.

You can suffer from B12 deficiency even if your blood levels are normal. When you body lacks B12, your red blood cells do not mature properly and are much larger than normal, and homocysteine accumulates in your bloodstream, damaging your arteries and brain cells. Also be sure that your doctor checks for diabetes, which can damage blood vessels that supply the brain, heart and other organs. Diabetics may suffer loss of memory long before they are diagnosed as having diabetes. While we await further studies, protect your memory with a lifestyle that will help you avoid diabetes, heart attacks and strokes. Control your weight, eat a wide variety of plants, limit refined carbohydrates and get plenty of exercise. For more on preventing Alzheimer's and other forms of dementia, see report #G101.

Is rope jumping a good exercise for fitness?

The fitness benefit from any exercise depends on how fast you move, whether it’s jumping, running, cycling or any other activity. Jumping rope has to be a vigorous sport, because you must spin the rope at least 80 times a minute to keep it from tangling. Most people use more energy when they jump rope than when they run. Jumping 80 times a minute uses the same amount of energy as running a mile in less than 8 minutes, a fairly rapid clip for most people. If you enjoy rope jumping, do it at a pace that is comfortable to you and stop when you feel discomfort.

To use rope-jumping for fitness, you need to be skilled enough to jump continuously for twenty to thirty minutes, and jumping that long and fast requires that you be in good shape. All you need is a ten-foot rope. The ends of the rope should barely reach your armpits when you stand on the middle of it. You don’t need special shoes, but sandals or loose shoes are likely to cause tripping. Start out by spinning the rope forward so you can see it as it passes. Bend your knees to absorb the shock of landing and protect the force of your feet striking the ground. To keep yourself from falling, bend slightly forward at the waist. Start out gradually and work up to thirty minutes three times a week.

Monday, September 05, 2005

Should you restrict salt?

In February 2005 the Center for Science in the Public Interest, a consumer advocacy group, sued the federal government for failure to act on the evidence that salt kills 150,000 Americans each year. The average American consumes 4,000 milligrams a day. Government spokesmen recommend salt levels below 2,300 milligrams (1 teaspoon) a day. The American Heart Association recommends 1,500 mg a day.

Excess salt intake raises blood pressure in some people by expanding blood volume. However, before you go out and try to avoid all salt, realize that your body needs some salt and severe salt restriction can be harmful. Severe salt restriction causes high blood pressure by causing the adrenal glands to release large amounts of aldosterone and the kidneys to release renin. Both hormones constrict arteries to cause high blood pressure. People on salt-wasting diuretics should also not try to restrict salt because they would then be at high risk for salt deficiency. Athletes have to be very cautions about salt restriction. Since sweat contains huge amounts of salt, athletes who restrict salt are in danger of developing fatigue, muscle damage and cramps caused by low salt levels.

If you have high blood pressure and are not on diuretics that drain salt from your body, it is reasonable to restrict salt. If you are a regular exerciser and feel tired or become injured, have your doctor draw blood levels of salt. You may find that you need to increase your intake of salt, particularly during exercise in warm weather. If you do not have high blood pressure, high cholesterol, diabetes or other risk factors for heart attacks and strokes, there is little evidence that you will benefit from severe salt restriction. However, future research may change this recommendation. Processed foods and fast-food restaurant fare contribute almost 80 percent of the salt to the American diet, and a healthful diet is low in these foods. The diet I recommend is a modified DASH diet; see report #8614.

Saturday, September 03, 2005

What causes most sports injuries?

Running seems like a safe sport, so many people are surprised to learn that it causes frequent injuries to muscles, tendons, bones and joints. During running, your foot strikes the ground with a force equal to three times body weight, a force more than double that of walking. Many common running injuries have bio-mechanical causes. For example, pain in the side of the right knee is often treated just by getting the runner to stop running on the roads. To facilitate drainage, roads slope a few degrees from the middle to the sides. Running on the side of a road, facing traffic, causes the right leg to be higher than the left and a larger proportion of the force of the foot strike to be transmitted up to the lateral part of the knee of the higher leg.

Pain behind the kneecap is often treated with special inserts in shoes. When you run, you land on the outside bottom part of your foot and roll toward the inside. This causes the lower leg to twist inward at the same time that the kneecap is pulled by the quadriceps muscle in the opposite direction. This causes the kneecap to rub against the long bone of the upper leg. Special inserts can be placed in running shoes that limit rolling in of the foot and prevent kneecap pain. For more on Runner's Knee see report #9639.

Bio-mechanics can explain injuries in other sports as well. Low back pain in bicycle riders is often treated just by raising the handlebars. Bending over excessively places excessive stress on the lower back muscles. Raising the handlebar stem can decrease the forces on the lower back and cure the pain. If something hurts when you exercise, ask yourself what you can do bio-mechanically to eliminate the excessive stress on that part of your body.

Can I prevent "afternoon slump"?

If you feel tired most afternoons, you are normal. Studies of office workers and school children show that people work best in the early morning. As the morning progresses, they lose their ability to concentrate, go out to lunch and function way below their capacity for the rest of the day. The best time to use your mind effectively is just after you wake up. When you have to write a report or letter, prepare for an exam, or perform difficult calculations, do it in the morning or shortly after you wake from a nap.

Tiredness is a signal that your brain needs a rest. If you suffer from afternoon tiredness, find a quiet place to lie down during your lunch hour and take a nap. There is no good data to support the often-quoted recommendation that you should exercise when you feel tired because exercise perks you up. Some people report feeling more tired after a meal that contains a lot of sugar or starch, but no one has shown that eating or avoiding specific foods prevents afternoon tiredness. Some people take a prescription drug called modafinil, which has been approved for treatment of narcolepsy, a serious medical condition that causes people to suddenly fall asleep. This can work if you take it only on the rarest of occasions, but no drug replaces sleep as a treatment for tiredness, and as keep on taking it, it can lose its effect. The only effective treatment for tiredness is rest. If you think you may have a sleep disorder that is making you tired all day, see report #G166 on Sleep Apnea.

Is T'ai Chi a good sport for seniors?

T'ai Chi is a specific training program aimed at teaching people how to maintain balance so that they can withstand the attack of an enemy and remain on their feet. It involves slow, purposeful movements that apply the same forces on muscles that require far heavier forces with faster movements. So T'ai Chi strengthens muscles with far less likelihood of injury.

Older people often lose coordination and are at increased risk for falling. With T'ai Chi, an older person can get the same strengthening of muscles and balance control with slow movements that a younger person gets by using far faster movements with much greater force on muscles. It can help older people improve balance, which can protect them from falling and breaking their bones. It is also a safe way to build muscle strength. The risk of injury in T'ai Chi is very low, which is an advantage at any age but exceptionally important for older people who are starting a new exercise program. See report #1550 for more tips on starting a new exercise program.

Friday, September 02, 2005

Will I live longer if I exercise?

Many recent studies show that people die from inactivity, not just from aging. We know that as people age, they lose muscle, their immunities weaken and because of their weakened immunity, they are more likely to die of cancer and infectious diseases. As you age, you lose your ability to kill germs because of lack of muscle. When germs get into your body, you must make white blood cells and proteins called antibodies to kill them. Antibodies and cells are made from protein and the only place that you can store extra protein is in your muscles. When you have large muscles, you have a ready source of protein to make antibodies and cells. When you have small muscles, you have a very limited source of amino acids to make protein, so your immunity may be inadequate for its job of killing germs.

You need antibodies to control cancer cells also. Each day, every healthy body makes millions of cancer cells. Your white blood cells and protein antibodies are necessary to ferret out and kill these cancer cells. You develop cancer when these cancer cells survive and start growing. Having large muscles gives you the source of protein to make antibodies that kill cancer cells as well as germs. Furthermore, when your skeletal muscles are small, so is your heart muscle. A strong heart can withstand arteriosclerosis and infections that can kill a weak heart.

Lack of exercise causes muscles to get smaller. With aging, it takes increasingly longer to recover from exercise. When older people get injured or get tired too soon or feel sore too early, they do less and less or they stop exercising altogether. Instead, they should be exercising more intelligently so they can retain their muscles. A major advantage of competing in sports at any age is that you can learn good training techniques and how to avoid injuries. If you can exercise into your nineties and beyond without quitting or getting injured, you can retain muscle mass, keep up your immunity and live longer and healthier. See report #1813.

Does cooking destroy important enzymes in foods?

Many people believe that fresh fruits and vegetables always contain more nutrients than cooked ones, but cooked carrots have higher levels of antioxidants than fresh carrots. Cooking carrots in the presence of a small amount of oil or butter increases the amount of two antioxidants called beta carotene and phenolic acid. Cooking also increases the amount of lycopene you get from tomatoes. Cooking breaks the plant cells open to increase the absorption of these antioxidants and other beneficial plant chemicals. Adding a little oil or butter increases absorption of fat soluble chemicals.

Some vitamins are affected by cooking, but you'll still get plenty. The enzymes in food that are destroyed by heat are of no use to you; your body makes the enzymes you need to digest your food. Most of the nutrients in food (minerals, proteins, fats, carbohydrates) are not destroyed by heat, and many common foods are unpalatable or unsafe if they are not cooked. I recommend eating the widest possible variety of fruits and vegetables, raw or cooked, and fresh, frozen, canned or dried. For more on food enzymes see report #1451

Why do some people develop allergies while others don't?

Allergies may be caused by lack of work for your immune system. One report from Austria showed that children who are exposed to farm animals before they were one year old had a much lower incidence of asthma and hay fever. When a germ gets into your blood stream, you make proteins called antibodies that attach to and kill that germ. If you have few infections early in life, your antibodies look for something to attack, even if it is not an invading germ. It may attack dust mites or cat dander or ragweed pollen. However, before you expose your young child to lots of dirt and sources of infection, realize that this is just a theory, has not been proved yet, and may be wrong. Also see report #9949.

Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey. Lancet, 2001, Vol 358, Iss 9288, pp 1129-1133.