Thursday, January 31, 2008

Sightseeing Cyclists Should Pedal Slower

Anything you can do to strengthen your legs will make you more efficient when you ride. Research from Norway shows that the stronger you are, the slower and more efficiently you pedal when you are going at a relaxed pace. Fourteen healthy subjects performed supervised heavy lifting (two sets of the heaviest weight that they could lift 12 times in a row) for 12 weeks, including two days per week of squats and leg curls. They improved by 20 percent in the squats and 12 percent in their leg curls. At the end of the study, their increased strength caused them to use a pedal rate that was about 10 revolutions per minute slower during cycling at half their maximal power output. They used three percent less energy to do this. Journal reference

When you are trying to go as fast as you can, use a fast cadence between 80 and 100 revolutions per minute. However, when you are sightseeing, pedal at 60 to 70 revolutions and you will use less energy to go the same distance. More on the best cadence for all types of cycling

Wednesday, January 30, 2008

Caffeine: Why it helps during exercise

In endurance events, the first cause of fatigue is loss of muscle sugar, so athletes do whatever they can to preserve sugar levels. Caffeine causes the body to produce large amounts of adrenalin, which causes fat to be released from fat cells and float in the bloodstream. This extra fat is taken up by the muscles and used for energy, thus preserving the body's limited stored supply of muscle sugar. When muscles run our of sugar, the athlete requires more oxygen to do the same job, slows down, fatigues earlier, and has difficulty maintaining his performance.

A questionnaire from competitors at the 2005 Ironman Triathlon World Championships showed that seventy-three percent of the athletes believe that caffeine improves performance and 84 percent believe it improves concentration. During competition, 65 percent used cola drinks and 24 percent used caffeinated gels. Although caffeine can increase risk for heat stroke and theoretically can cause irregular heartbeats, almost none of the athletes reported suffering any side effects from taking caffeine.
Journal reference; free fitness and health newsletter

Monday, January 28, 2008

Vitamin D Deficiency Linked to Heart Attacks

More than 75 years ago, we learned that lack of vitamin D causes rickets, bone deformities and failure to grow in children. Twenty years ago, reports started to appear showing that lack of vitamin D also impairs your immunity to limit your ability to kill germs. This was followed by studies showing that it also increase risk for certain cancers. Now the Framingham Offspring Study from Harvard tells us that low blood levels of vitamin D increase risk for heart attacks (Circulation, January 2008).

The authors followed 1700 participants (mean age 59) without prior cardiovascular disease for five years. Those with low blood levels of active vitamin D at the onset had one and a half times the chances of suffering a heart attack. Those with low vitamin D and high blood pressure had twice the risk. At this time, nobody knows why lack of vitamin D increases heart attack risk.

Dietary sources of vitamin D include deep-water fish and fortified cereals, but most North Americans meet their needs for vitamin D from sunlight and not from their diets. If you do not get out in the sun at least a few times a week, ask your doctor to check your blood levels of vitamin D. People with dark skin and those who are overweight are most likely to be deficient. Free newsletter

Saturday, January 26, 2008

Plant Omega-3's Better than Fish Oils

Omega-3 fatty acids protect against heart attacks, inflammatory diseases such as rheumatiod arthritis, depression, and attention deficit disorder. You probably know that you can get omega-3s in seafood or fish oils. However, the omega-3 fatty acids in seeds such as whole grains may be even more important in maintaining your health than the omega-3s from fish.

Omega-3 fatty acids are the least stable fats in our diet. Whole grains contain vitamin E to keep the omega-3s fresh and prevent them from turning rancid, but omega-3 fatty acids in fish are not protected by vitamin E and therefore turn rancid much more quickly than the omega-3 fatty acids in seeds.

Three large studies, The Lyon Heart Study, the GISSI Prevenzione Trial, and in The Dietary Approaches to Stop Hypertension Study have established that omega-3 fish oils help to prevent heart attacks and reduce pain and swelling in diseases such as arthritis, psoriasis, and possibly even asthma. Other research shows that the omega-3 alpha linoleic acids in seeds, nuts, beans and whole grain may be as necessary as the omega-3s in fish oils to prevent heart attacks. Journal references

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. Long- chain fish omega-3s enter blood and cells more rapidly and produce more rapid effects than short chain plant omega-3s.

Over the long haul, humans must get omega-3s from plants, as well as fish, because all omega-3s break down very quickly when exposed to oxygen in your body, and you need large amounts of vitamin E to prevent omega-3s from turning rancid. Fish oils are extremely low in vitamin E, while virtually every seed or plant source of omega-3s is loaded also with vitamin E. So your body stores far more short chain omega-3s from plants in your body fat.

Dietary fats are classified by their chemical structure into saturated, polyunsaturated and mono unsaturated. The polyunsaturated fats are further sub-classified into omega-3, omega-6 and omega-9. Omega-6 polyunsaturated fats form prostaglandins that cause clotting, a thickening of the blood and constriction of arteries that cause heart attacks.

On the other hand, omega-3 polyunsaturated fats prevent heart attacks and high blood pressure by helping thin blood, relax arteries and prevent clotting. Over millions of years, humans have consumed a diet that contained approximately equal amounts of omega-6 and omega-3 essential fatty acids, but over the past 150 years, humans have increased their consumption of omega-6s by taking in vegetable oils from the seeds of corn, sunflower, safflower, cotton and soybeans.

These oils are used in most prepared foods, frozen foods, margarines, French fries, potato chips, and bakery products. North Americans eat a diet with a ratio of omega-6 to omega-3 fatty acids that is almost 20 times higher in omega-6s than omega-3s, instead of the earlier ratio of about 2:1. This abnormally high intake of omega-6s blocks arteries and causes swelling throughout the body. To meet your needs for short chain omega-3 fatty acids found in plants, eat plenty of green leafy vegetables, and seeds such as flaxseed, whole grains, beans and nuts. More on omega-3 fatty acids

Tuesday, January 22, 2008

Eight Glasses of Water a Day: No Health Benefit

Eight glasses of water a day will just give you a lot of extra trips to the bathroom. Drinking extra water does not "flush out toxins" or offer any other useful function.

Why do so many people believe this rule? The number originally came from the National Academy of Sciences of the United States Food and Nutrition Board, which publishes recommended daily allowances of nutrients. The 1945 edition of the Food and Nutrition Board said "A suitable allowance of water for adults is 2.5 liters (about 8 cups) daily in most instances." This amount is based on the calculation of one milliliter of water for each calorie of food. HOWEVER, the Board also noted that most of the water you need is in the food you eat.

All foods contain water. Even the driest nut or seed has a lot of water in it. Furthermore, when food is digested, it is converted to energy, carbon dioxide and WATER. Most people can get the fluid the body needs from food, and they only need to drink enough water to prevent constipation.

Researchers have showed that plain water is not needed as long as enough fluid is obtained from other drinks and food. Twenty-seven healthy men consumed one of two diets for three-day periods and were studied in a lab setting. The first diet included plain water while the second omitted it, relying on only foods and beverages other than water for fluid. None of the nine measures of hydration were affected. Journal reference

A reasonable amount for a healthy human is one cup of water or any other fluid with each meal. If you have a problem with constipation you may not be drinking enough water, but if you are not constipated, you are getting plenty. You'll also want to replace fluids whenever you sweat a lot, particularly when you exercise or in hot weather. Drink water whenever you feel thirsty, but there's no health benefit from forcing yourself to drink eight glasses of water a day.

Monday, January 21, 2008

Fewer Hard Workouts May Make You a Better Athlete

How much time should you spend working at your maximum level in your sport, compared to miles or days spent going at a relaxed pace? Researchers at the University of Madrid in Spain divided competitive distance runners into two groups. One group did frequent intense workouts and fewer slow recovery miles, while the second group did fewer intense workouts and more slow miles. At the end of five months, the runners who did fewer intense workouts and more recovery miles improved far more than those who ran fewer miles and spent a lot of their time trying to run very fast. Journal reference

All competitive athletes from marathon runners to weight lifters know that they must exercise intensely to compete successfully in sports. However, every time you exercise intensely, your muscles are damaged and you feel sore on the next day. If you try to exercise intensely when your muscles are sore, you are liable to injure yourself, break down, or become chronically fatigued with muscles hurting all the time. So athletes train by taking a hard workout that makes their muscles sore, and going easy for as many days as it takes for the soreness to go away. This study shows the importance of allowing adequate recovery time between intense workouts. Recovery workouts make your muscles more fibrous so they can take more abuse when you exercise on your hard days. Principles of training

Sunday, January 20, 2008

Cold Toes Can Mean Diabetes

Painfully cold toes can ruin outdoor sports on cold days. We solve the problem with adhesive toe-warmer packets on our socks. However, if your toes feel cold even when it is not cold outside, or if you have loss of feeling or tingling as well, you need a complete work-up for causes of nerve damage. Numb, cold or tingling feet can be one of the first symptoms of diabetes.

Nerves can be damaged by something pinching or stretching them, such as excessive pressure from moving a limb repeatedly (as in carpal tunnel syndrome in your hand), scar tissue, or a disc problem in your back. Nerves can also be damaged by diabetes; lack of a vitamin (such as B12 in pernicious anemia); infections such as Lyme disease, shingles and herpes; poisonings by substances such as mercury or lead, or by diseases such as multiple sclerosis. You should never ignore a neuropathy because many causes are controllable before you suffer permanent damage to your nerves. Check with your doctor to find the cause of any neuropathy.

Thursday, January 17, 2008

How to Lower Your Chances of Dying Early

Researchers at National Cancer Institute in Bethesda showed that engaging in physical activity for at least three hours per week appears to decrease chances of dying early by more than 25 percent.

The investigators evaluated the exercise habits of 252,925 adults aged 50 to 71 years who were enrolled in the National Institutes of Health–American Association of Retired Persons (NIH-AARP) Diet and Health Study. 7900 deaths occurred during 1,265,347 person-years of follow-up. Those with the relatively modest exercise program of 30 minutes on most days of the week, or vigorous exercise of at least 20 minutes three times per week, were 27 percent less likely to die during the followup period. The authors state that: "Our findings suggest that engaging in any physical activity by those who are currently sedentary represents an important opportunity to decrease the risk of mortality." Journal reference

Another study from India showed that former athletes who continue to exercise all their lives are far less likely to suffer heart attacks than former athletes who do not continue to exercise. Compared to sedentary former athletes, active older athletes weigh less, have less body fat, lower total cholesterol, bad LDL cholesterol, triglycerides and ratio of total cholesterol to good HDL cholesterol than sedentary older athletes, all signs of decreased risk for heart attacks. Surprisingly, sedentary older athletes have higher cholesterol and triglyceride levels than sedentary older non-athletes. It takes a lot of muscle to be a good athlete. Insulin, insulin-like growth factors and growth hormones give people large muscles and bones to make them stronger. However, these same hormones also cause the body to store fat. So former athletes who stop exercising are more likely to be fat and have higher cholesterols because of these same hormones.

The message is: start exercising, and once you start, keep it up for the rest of your (long) life.

Tuesday, January 15, 2008

Cofactors May Explain Why Some Get Colon Cancer, Others Don't

Although scientists are not sure what causes colon or rectal cancers, they know that they are associated with lack of exercise, eating too much meat, and the human wart virus (HPV). A study from Sendai, Japan shows that men who spend a lot of time walking are at reduced susceptibility to developing colon cancer.

An extensive review of the world's literature shows that colorectal cancer occurs far more frequently in prosperous industrialized countries, and that dietary factors may cause up to 75 percent of these cancers. You are increased risk for colon cancer if you are overweight, and exercise reduces your risk. Rectal cancer is not affected by obesity or exercise, and may be associated more with infection, such as with the HPV virus that causes genital warts. Since the vast majority of people who are infected with HPV do not get cancer, we have to explain why some do. The leading theory is that of cofactors: some combination of infectious agents, genetic susceptibility or lifestyle factors. I think that rectal cancer requires some kind of infection, but you do not develop the cancer unless you also smoke, lack vitamin D, eat a lot of meat, or some other combination of factors. Colon cancer appears to require some combination of factors such as lack of vitamin D, eating meat, not exercising or not eating enough foods from plants. Journal references; more on colon cancer

Monday, January 14, 2008

Walking for Fitness

Walking is a very safe sport because it rarely causes injuries. Running causes injuries frequently because you take both feet off the ground at the same time and land with a tremendous force that can tear muscles and shatter bones. On the other hand, when you walk, you always keep at least one foot on the ground and land with minimal foot strike force.

If you want to walk to become fit, you need to move quickly. You should exercise vigorously enough to increase your heart rate at least 20 beats a minute higher than when you rest. That means you will be breathing harder and probably perspiring. There are two ways to increase your walking speed. You can take longer steps or you can move your feet at a faster rate. To lengthen your stride, swivel your hips so you reach out further forward with your feet. This will cause you to twist your body from side to side, which will tend to make you point your toes inward when your feet touch the ground. When you point your toes in, you lose distance. Try to point your toes forward with each step.

To move your feet at a faster rate, you have to move your arms faster. Every time you move one leg forward, your arm on the same side moves back and the arm on the other side moves forward. Your legs will only move as fast as you can move your arms. Bend your elbows so you can move your arms faster. The fulcrum of your arm-swing is at your shoulder. The straighter you keep your elbows, the longer it takes your arms to swing forward and back. Bending your elbows shortens the swing and helps you speed up your pace. More on how to start an exercise program

Friday, January 11, 2008

Growth Hormone Consequences

Many top athletes in virtually every sport that requires strength take Human Growth Hormone, or HGH. Since HGH is taken "under the table", virtually no studies have been done to track the consequences of its use in athletes. However, a study from Johns Hopkins shows that children who are growth hormone deficient and are given growth hormone for one year develop a progressive thickening of their heart muscle and of the blood vessels leading to their brains. They are 52 times more likely to have an atherosclerotic carotid plaque after one year. (The Journal of Clinical Endocrinology & Metabolism, Volume 92, 2007)

A very famous athlete died suddenly for no apparent reason. The autopsy showed that she had a huge heart that had outgrown its blood supply. HGH enlarges the heart without proportionately enlarging blood vessels that nourish it. HGH can make you a better athlete, but at a price. Athletes are so guided by their desire to win that they often are willing to ignore the consequences of the drugs that they take.

Thursday, January 10, 2008

The Latest Diet Books: Recipe for Success?

Before you spend your money on the latest diet book or weight loss gimmick, remind yourself that the ONLY ways to lose weight are:

1) Take in fewer calories,
2) Burn more calories, or
3) BOTH.

ALL of the popular diet books and programs, regardless of the "scientific" explanations they give, recommend menus that give you 1500-1800 calories or less per day. For most people this means you will be taking in fewer calories. You can lose weight on ANY OF THEM, but ask yourself: Is this a way of eating I can follow for the rest of my life? (If not, you will regain the weight as soon as you go back to your old eating habits.) And do the foods they tell me to eat supply all the nutrients my body needs? Most people can eliminate foods and food groups for a short time without any harm, but eventually you will create deficiencies if you do not eat a wide variety of foods, with lots of fruits, vegetables, whole grains, beans and other seeds. Don't believe that you can make up for what's missing with pills: a lousy diet with supplements is a lousy diet.

Your doctor may consider Surgery or prescription medications if you are critically obese, but these measures also require permanent diet changes and exercise for long term success.

If you are thinking of trying a supplement or spa treatment that promises to take off pounds with no effort, use the old rule: "if it sounds too good to be true, it usually is."

- Products that remove water (diuretics) or empty your colon (laxatives or colon cleansers) can cause you to drop several pounds in a day or two, but this is strictly temporary and does not remove any fat. You do not need to "cleanse" or "remove toxic waste products" to lose weight or for any other reason. Prolonged use of diuretics or laxatives can be dangerous.

- Most products that claim to "rev up your metabolism" or "burn fat" contain stimulants. Many plants contain stimulants, and you will get the same effect from "natural" or herbal weight loss products that you get from drinking lots of coffee or tea. Stimulants cause you to burn more calories and you will lose weight at first, but you need to take more and more as the days go by, and they can cause unpleasant, even dangerous side effects.

- There are no creams that will dissolve fat.

- Magnets placed over an acupuncture point don't cause weight loss.

- Eating collagen before you sleep does not make your body burn fat.

- Fat absorbers (chitin products) bind to small amounts of fat, but they cost about $35 to block the amount of fat in a Big Mac; in larger quantities they cause terrible gas and diarrhea.

- Pills or gimmicks that promises to get rid of cellulite are useless because cellulite doesn't exist. It's just plain fat.

- The only function of a body wrap is to make you sweat, and thus lose water. They claim you will lose 14 inches in 2 hours? So you lose 1/4" in the circumference of your legs through dehydration; they measure each leg, your waist, your hips, your arms, etc., total up the measurements and voila, you've lost 14 inches. You can get the same effect if you take your measurements before you go to sleep at night and after you wake up in the morning. Water loss is not fat loss. Here's their guarantee: "The inches will stay off unless you regain the weight." They fail to mention that OF COURSE you will regain the weight as soon as you take a drink of water.

Losing weight and keeping it off takes a permanent lifestyle change, involving both healthful eating and exercise. You'll find lots of help in the Nutrition section and the Fitness section of DrMirkin.com, and in the free Good Food Book

Wednesday, January 09, 2008

Bleeding Gums? Treat for Infection

One in 10 people suffers from periodontal diseases, characterized by bleeding in the gums when you brush your teeth, loosening of the teeth and damage to the structures that help the teeth stay in place.

These problems are caused most commonly by infections by three Gram-negative bacteria: Porphyromonas gingivalis, Bacteroides forsythus and Actinobacillus actinomycetemcomitans. The body responds to these infections by producing various cytokines (IL-1, IL-6, IL-8, TNF-alpha), inflammatory mediators (PGE2), and matrix metalloproteinases (MMP-2, MMP-3, MMP-8, MMP-9). Viruses, such as cytomegalovirus and Epstein-Barr virus) can also cause periodontitis. Conventional treatments for periodontitis aim to eliminate bacterial plaque by scrubbing, cleaning and prescribing antibiotics. Many dentists also prescribe anti-inflammatory drugs to decrease inflammation.

If your gums bleed when you brush your teeth or you have lose teeth, ask your doctor or dentist to try a short course of antibiotics for yourself and your spouse or partner. I often prescribe a combination of metronidazole 250 mg four times a day, and Biaxin 500 mg twice a day for one week. Other options include Zithromax, Dyanbec, doxycycline, minocycline, or a quinolone antibiotic. More on the link between gum disease and heart attacks

Monday, January 07, 2008

Weight Loss Hindered by Cold Weather

Many people gain weight during the cold months even if they exercise and watch what they eat. One reason may be that 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 must 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 its 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. More on weight loss

Friday, January 04, 2008

Cold Hands: Don't Just Suffer

If your fingers turn white and start to hurt when you're out in the cold, you may have a condition called Raynaud's phenomenon. On exposing your fingers to cold, the blood vessels close, skin turns white and their temperature drops. When the temperature drops to 59 degrees, your body tries to save your skin by opening the blood vessels and the skin turns red and starts to itch and burn. If you warm your hands at this point, your skin will not be damaged, but if you do not get out of the cold, the blood vessels in your hands can close and the temperature in your hands can drop to freezing, resulting in frostbite.

People who have Raynaud's phenomenon have blood vessels in their hands that do not open when the skin temperature reaches 59 degrees. Several diseases, smoking or using vibrating equipment can cause Raynaud's phenomenon.

Wear two or more layers of gloves and mittens. When your fingers feel cold, swing your arms very rapidly about your shoulder with your elbow straight. This will drive blood, like a centrifuge, into your fingers and warm them.

The blood pressure drugs called calcium channel blockers, such as Nifidipine, can help to treat and prevent Raynaud’s phenomenon . Another option is nitroglycerin ointment, a prescription medication that is used to treat angina. When applied to the forearm, it opens blood vessels leading to the hands. Check with your doctor to see if either of these medications would be appropriate for you. More on frostbite

Thursday, January 03, 2008

Oveweight Children Risk Heart Attacks as Adults

Two new studies in the same issue of the New England Journal of Medicine show the probable impact of childhood obesity on heart attack rates. The first study, based on annual height-and-weight measurements in some 275,000 Danish schoolchildren, followed their health after age 25. Researchers found that being overweight in adolescence predicts higher risks for heart attacks in later life. The present high rate of obesity in adolescence is projected to increase the prevalence of obese 35-year-olds in 2020 to a range of 30 to 37 percent in men and 34 to 44 percent in women.

The second study predicts that heart attack rate will increase between 5 percent and 16 percent by 2035, with more than 100,000 excess cases of coronary heart disease attributable to the epidemic of obesity. Obesity in childhood increases risk for coronary heart disease during adult years. Efforts to regulate advertising of junk food, change farm subsidies, and provide funding for decent lunches and regular physical activities at school can help to reverse this trend. Journal references; more on healthful eating for children

Tuesday, January 01, 2008

Why Exercise Protects Your Memory: New Research

Recent research shows that a regular exercise program can help to prevent some of the loss of memory that comes with aging. A part of your brain called the hippocampus is the control station for memories that you store in other parts of the brain. Another brain structure called the prefrontal cortex is the central station that assembles data from other parts of your brain when you want to recall something from your past. Aging causes the brain to shrink and you lose synapses that transmit messages from one nerve to another.

Exercise causes the brain to produce a substance called Brain Derived Neurotropic Factor (BNDF) that strengthen old synapses and causes new one to grow. Researchers used MRIs of their human subjects to show that an exercise program of an hour a day, four days a week for three months caused new neurons to grow in the hippocampus. Several previous studies showed that exercise enlarges the hippocampus in rats and doubles or even triples the rate of the formation of new nerves. However, one way that rats differ from humans is that most of them like to run and need no encouragement to spend several hours a day on a treadmill.

There is also emerging evidence that physical activity may be protective against neurological disorders, including Alzheimer's and other forms of dementia, Parkinson's disease, strokes and spinal cord injuries. If you are not a regular exerciser, check with your doctor and get started. Journal reference; more on preventing memory loss with exercise; more on Alzheimer's