For April 23, 2018
- Ergogenic Effects Of Creatine
Ergogenic Effects Of Creatine
By ELSEVIER, PARIS
Objectives. - In the last few years many athletes and persons engaged in recreational sports activities have begun using creatine supplementation. Creatine feeding is possible by oral administration of creatine monohydrate. The objectives of this paper are to recall the mechanisms by which creatine might improve performance, to discuss the known effects of creatine supplementation on exercise performance, and to examine its side effects.
Topics. - The rate of turnover of creatine for a 70 kg male has been estimated around 2 g/d. Creatine is partly supplied by the diet that provides I g/d through meat and fish. Recent studies have shown that ingestion of about 20 g of creatine monohydrate per day is able to modulate total muscle creatine, free creatine and phosphocreatine. The aim of this article is to provide an overview of recent knowledge on the effects of creatine supplementation on exercise performance. Many studies demonstrate that creatine supplementation has beneficial effects on performance of short-duration exercises, during repeated isokinetic or isometric contractions of the quadriceps muscle, jumping or high-intensity cycling exercises. The beneficial effects of creatine supplementation on performance capacity are strongly related to the efficacy of the treatment for enhancing muscle creatine pool. If is thus clear that phosphocreatine stores play a key role for ATP resynthesis during muscle contraction and recovery. The improvement in performance following creatine supplementation is dependent on the characteristics of the exercise. It has been suggested that human skeletal muscles have an upper limit for total creatine concentration. In contrast with sedentary subjects, in athletes and well-trained subjects who have high initial total creatine concentrations in skeletal muscle, only a slight improvement in exercise performances is expected. Taken together, the results of most studies published to date suggest that only performances of repetitive high-intensity exercise bouts are positively affected by creatine supplementation. During this type of exercise, the expected increase in total creatine contributes to the fast resynthesis of phosphocreatine during recovery. Until recently, it was well accepted that except for a slight increase in body weight, no adverse effects have been associated with creatine supplementation. However, a recent report described a clinical case of renal dysfunction that was associated with oral creatine supplementation.
- Physician Group Offers Health Tips For The New Millennium
Physician Group Offers Health Tips For The New Millennium
- By MEDICAL TRIBUNE NEWS
The American Medical Association (www.ama-assn.org) has released its list of health tips for the new millennium. They emphasize eating right, avoiding weight gain, quitting smoking and handgun safety.
The AMA predicted that obesity would become an even more serious problem for Americans in 2000 and also stated that ``tobacco use remains the leading preventable cause of death in America.''
Dr. Richard F. Corlin, speaker of the AMA House of Delegates, and a gastroenterologist based in Santa Monica, Calif., said that getting Americans to quit smoking was one of the two most crucial issues for the next century. The second was the need for handgun safety, especially in households with children.
Parents should ensure a safe environment for children and adolescents, the physician group advised. Suggestions included avoiding tobacco use around children, locking firearms out of kids' reach, keeping toxic poisons stored where they cannot be discovered, placing sleeping babies on their backs to help prevent sudden infant death syndrome (SIDS) and ensuring car safety. The AMA also emphasized opening up dialogues with children and adolescents about avoiding smoking, drinking and drugs. Immunization was recommended as a crucial protective measure for the new century.
Adults were also cautioned on their Internet use when seeking legitimate health information. Corlin stated that while patients were increasingly educating themselves about health issues _ something he found encouraging _ a great deal of information on the Internet ``is not valid. Be careful what sites you get your information from. Make sure it's from a scientific source,'' he said.
Seniors were advised to exercise, manage cholesterol and metabolism through proper diet and medication, eat a diet high in fiber and low in fats and sugars, and recognize and seek treatment for depression, if necessary.
Elderly adults and their caretakers should prevent dangerous falls by tacking down scatter rugs and clearing stairwells. Pay attention to heat stress, and avoid hot water accidents by making sure faucets are color-coded and handles are easy to turn. Caretakers should also learn to recognize signs of abuse in the elderly and report them to authorities when necessary.
Many of the AMA's new initiatives were focused on preventive care. ``Preventive care is absolutely essential because many of the diseases that we're dealing with now have substantial asymptomatic faces before they begin to cause any difficulties,'' said Corlin. These include high blood pressure, elevated cholesterol and diabetes. ``Just because somebody's feeling well doesn't mean they don't have any health problems,'' he noted.
``The best way for individuals to begin improving their health in the Year 2000, and beyond,is by establishing a partnership with your physician to help you take charge of your health,'' according to the AMA.
- Hormone Induces Weight Loss
Hormone Induces Weight Loss
Injections of Leptin Shown to Curb Appetite in Young Girl
(MSNBC Health, September 15 1999) � For the first time, injections of the hormone leptin have been shown to curb appetite and induce weight loss in a human, a new study says. Scientists caused a stir four years ago when they announced that leptin could evoke weight loss in mice, but until now, a direct role in human obesity had not been confirmed.
THE FINDINGS by doctors at Addenbrooke�s Hospital in Cambridge, England, provide important clues as researchers try to decipher the genetic and environmental factors in obesity. The work could lead to medical treatments for some forms of the condition. Leptin is a protein produced by fat cells. It is supposed to signal the brain to stop eating, but the signal does not get through properly in some overweight people.
The study published in Thursday�s edition of The New England Journal of Medicine involved a severely overweight 9-year-old girl who suffered from a rare genetic defect in which her body produced virtually no leptin. While the girl�s condition is uncommon, the researchers, led by Dr. I Sadaf Farooqi, believe the findings have implications for the general population.
Obesity is a major source of illness and death, and is the most common nutritional ailment in the United States, according to the Minnesota Obesity Center. The new work involved a girl from a Pakistani family who was born with a leptin deficiency. She was so overweight, she got liposuction at age six to remove fat from her legs and allow her to move around. She was constantly hungry and became disruptive when denied food.
In 1997, when the girl was 9 and weighed 208 pounds, doctors began administering daily injections of leptin. With the shots, her weight gain stopped abruptly. Her mother and doctor found that the girl began eating far less food than before, and stopped craving between-meal snacks. She began losing 2 to 4 pounds per month. After a year of treatment, she had lost 36 pounds, virtually none of it muscle and all of it fat.
In addition, her level of physical activity increased 19 percent during the first 12 months of therapy. �Treatment of this 9-year-old patient with congenital leptin deficiency with recombinant leptin led to a sustained reduction in weight, predominantly as a result of a loss of fat,� said Farooqi.
WON'T BE EASY
In an editorial in the New England Journal of Medicine, Dr. Michael Rosenbaum and Dr. Rudolph Leibel of the Columbia University College of Physicians and Surgeons said further research on leptin �may help to move us closer to an effective pharmacologic treatment of obesity.� But many factors besides leptin affect weight, and people should not conclude that leptin injections would make losing weight easy, they added.
If anything, leptin might help some people stick to a diet by curbing their hunger and aid in keeping the weight off, Rosenbaum said. �The only thing that we know is that it decreases appetite in this child and in a mouse,� Rosenbaum said. �It�s not the be-all and the end-all to promote effortless weight loss.�
Leptin is being tested in ordinary fat people as an appetite suppressant. Preliminary findings from one study indicate that it isn�t a miracle cure, but shows some promise when combined with diet and exercise. Dr. Richard A. Dickey, President of the American Association of Clinical Endocrinologists, called the study �a great start,� adding that although doctors generally believe many factors are involved in human obesity, leptin is clearly important.
�It�s very possible that this child is a clue to appetite control and weight gain across a large portion of the population,� he said. �I think that everybody�s excited about the role of leptin.�
The Associated Press and Reuters contributed to this report.
- Hate Exercise? Positive Thinking Can Help
Hate Exercise? Positive Thinking Can Help
How to Make Exercise Feel Easier
(Prevention, August 1999) � Exercise feels good, right? Not for everyone -- especially if you're overweight or just starting out. You're hot and sweaty, your heart is racing, and you're breathing like a freight train.
And if you perceive this experience as negative, chances are you're not going to stick with it, says Joanne Kraenzle Schneider, PhD, a postdoctoral research fellow at Washington University School of Medicine in St. Louis and a registered nurse. But she suspects that if you shift your thoughts to more positive ones, you'll be more likely to continue exercising.
Makes sense, and a small pilot study she did supports this. More research is needed. In the meantime, when you're out for a walk or in an aerobics class and find yourself saying or thinking negative things, counter them with positives. Below are some common reactions to exercise and ways to look at them positively.
What You Think During Exercise How To Respond "I'm bored." Visualize a positive experience such as a favorite vacation, a get-together with friends or a childhood memory. Or focus on the details of your surroundings. "I hate to sweat." "Sweating's a good thing. It's cooling my body because I'm working hard, which will make me healthier." "I'm sore."* "I'm challenging my body to use different muscles I'm not used to using. I'm making progress and building muscles." "This is tiring." "I need to push through it. I'll feel energized later." "I don't like when my heart pounds so hard." "My heart is getting stronger. It's pumping blood and oxygen to all my muscles so they can work harder." "I don't like feeling hot." "I'm working my muscles and burning calories." "I don't like feeling short of breath." "This indicates I'm doing what I should be doing. My muscles need oxygen to move so I need to take in more oxygen." *Note: This refers to muscle soreness or achiness, not sharp pain or pain in your joints. If you're experiencing the latter type of pain, stop exercising, and see a doctor if it continues.
- Wonder Drug Reduces Body Fat and Increases Lean Muscle Mass?
Wonder Drug Reduces Body Fat and Increases Lean Muscle Mass?
(From "Ask Dr. Weil", August 1999) Conjugated linoleic acid (CLA) is a fatty acid that's been receiving all sorts of attention lately due to claims of miraculous weight loss, increased muscle mass and protection against cancer and heart disease, as well as improved immune function in people who take it. I usually write off most of these supplement-of-the-month phenomena as just hype, but a review of the medical literature turned up some compelling, albeit limited, studies.
Specifically, a single small study in Norway showed that research subjects who took 3,000 mg of CLA daily experienced a 20 percent reduction in body fat and a five percent increase in lean muscle. Another study at Kent State University in Ohio found that taking 7,200 mg of CLA per day increased muscle mass by five percent among beginning body builders compared with only 0.5 percent among beginners who trained without CLA. CLA supposedly prevents fat from being deposited into cells by speeding fat metabolism, but no one knows if taking it long term would have any negative side effects. Also, there's no reason to suppose that you will lose weight with CLA if you don't also change your diet and exercise habits.
I'm more skeptical of CLA's reputation for reducing the risk of cancer and heart disease. Supposedly CLA slows the abnormal rate of cell division that is characteristic of cancer, but I've seen no hard evidence that confirms this. Regarding heart disease, there's only one relevant study: Cholesterol levels and arterial fat deposits in rabbits dropped after they were given CLA for 12 weeks. The notion that CLA boosts immune function also comes from a single study showing that immune function improved among mice fed CLA for eight weeks.
All this is very preliminary data so I wouldn't be too quick to leap on the CLA bandwagon. We do know that CLA is found in fatty meat and dairy products, and if you're avoiding high-fat foods and dairy as most nutritionists recommend, you can't get much through your diet. And if you opt for CLA supplements, be aware that those on the market, made from sunflower and safflower oils, are notorious for causing flatulence and gastrointestinal discomfort.
- Fat Loss in a Bottle
Fat Loss in a Bottle
Here are some nutritional supplements on the market that can help your weight-loss process along.
Originally featured in: Men's Fitness May, 1999
It may sound like something out of a sci-fi novel, but thermogenesis could be the secret to losing your love handles.
Literally meaning "the creation of heat," it involves cranking up the calorie- and fat-burning processes in your body. While exercise and diet are the keys, many of us are genetically limited as to how much fat we can burn.
This is where modern science comes to the rescue: There are nutritional supplements on the market that can help the process along. The products discussed below won't work without a sound weight program and plenty of cardio, but they might be worth a try.
This fruit, also called "bitter orange," contains a naturally occurring fat-burner called synephrine. Citrus aurantium can increase your body's ability to burn fat and may exert a mild hunger-suppressant effect. It has only recently been introduced in supplement form and should be widely available toward the end of the year.
"Citrus aurantium is the ideal fat-loss aid for guys who have plateaued in their workout programs," says Douglas Kalman, RD, director of clinical research at Peak Wellness, a Greenwich, Connecticut�based health-care facility. The latest study performed at Peak Wellness on citrus aurantium showed no signs of potential side effects. Stay tuned.
You've probably heard of DHEA, a hormone-replacement therapy that some guys use to gain muscle mass and lose body fat. Unfortunately, DHEA is not very effective in guys under 35, and it's associated with some nasty side effects, including prostate enlargement, acne and premature baldness.
Earlier this year, an altered version of DHEA was introduced. It's called 7-keto DHEA, and research indicates that it works by preventing your metabolic rate from dropping when you're on a calorie-restrictive diet.
Kalman believes 7-keto holds great promise. "When individuals diet to lose body fat, their progress stops after a period of a few weeks," he says. "This version of DHEA can prevent this without the hormone-like side effects."
Caffeine and ephedra
These two controversial stimulants are thermogenic on their own but have an even greater effect on fat loss when combined. They are added to several ready-made drinks or pills found in health-food stores, sometimes referred to by their respective herbal names, guarana and ma huang.
The problem, again, is side effects. Overuse of caffeine and ephedra has been associated with increased heart rate, insomnia, nervousness and even death. "Scientific studies have shown that [the combination] works, but I'm not crazy about the potential for side effects," Kalman says. If you're on antidepressant medication, ephedra is not an option.
A recent study demonstrated that as little as 6 grams of pyruvate per day can enhance fat loss and increase muscle mass in guys who exercise regularly and follow a reasonably low-fat diet.
"I like this one because it basically has no side effects, it's all natural, and data shows pyruvate can not only effect fat loss, but can make you exercise harder and longer," says Kalman.
Yohimbine is a natural substance derived from the bark of two African trees. It is a potent vasodilator that first became popular because it increases the blood supply to the penis. In fact, yohimbine was the pre-Viagra impotence treatment for millions of men around the world.
Yohimbine also increases levels of norepinephrine, which has a marked effect on fat utilization by the body. However, it may cause stimulatory-type reactions such as dizziness, irritability, headaches, anxiety and increased heart rate.
"The side effects are pretty common," says Kalman. "Also, it can have negative interactions with antidepressant medications." If yohimbine strikes your fancy, stick to the prescription brand Yocon, or make sure over-the-counter varieties declare that they are standardized for yohimbine activity. Ask your doctor before trying it.
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