Animal Studies

Oral or intravenous administration of yohimbine in dogs has resulted in a significant elevation in plasma free fatty acids and an increase in sympathetic nervous system activity. Norepinephrine was significantly elevated following yohimbine administration. Furthermore, chronic oral administration resulted in a reduction in body weight and in food intake, suggesting that alpha2­antagonists may influence satiety. The lipolytic effect of yohimbine may result either from a direct action of yohimbine or from an activation of the sympathetic nervous system.

Human Studies

The interplay of beta-receptors and alphaTreceptors regulates the lipolytic response of adipose tissue to the catecholamines. A supplement which would inhibit the alpha2-receptors would theoretically increase the action of catecholamines on lipolysis. Yohimbine has been shown to effectively increase lipolysis.

An abundance of studies have been done investigating the lipolytic action of yohimbine in humans. In vitro studies using human adipocytes have indicated stimulatory effects of yohimbine on lipolysis when catecholamines are present.

Oral administration of yohimbine to humans has been shown to significantly elevate plasma glycerol and free­fatty acids. Furthermore, the effect of yohimbine was further enhanced during physical exercise when the levels of catecholamines are further elevated. Yohimbine also appears to stimulate norepinephrine levels by increasing sympathetic nerve activity.

When yohimbine was administered during a low­energy diet, patients lost significantly more weight than patients receiving a placebo Energy expenditure did not decline in the patients consuming yohimbine, while the placebo group experienced a 15% reduction in energy expenditure.

Safety and Toxicity

Alpharreceptors are present in a number of tissues including heart, arteries, lung, and adipose tissue. Therefore, yohimbine could react with any of these receptors and influence those tissues. However, both animal and human studies indicate that cardiovascular changes are either nonexistent or minimal following yohimbine administration.

Some side effects associated with yohimbine include feelings of panic, clumsiness, and confusion. There have also been reports of chills, nausea, and tremors. The prescription form of yohimbine is normally prescribed for impotence problems; therefore, individuals may experience heightened sexual arousal. Furthermore, there have been reports of mood disturbances and anxiety.

Another concern regarding yohimbe is the purity of the dietary supplement. Yohimbine is the major alkaloid of the plant and the active ingredient. The bark of the tree has been reported to contain 6% total alkaloids, 10-15% of which are yohimbine. Most dietary supplements have been standardized to 3% yohimbine. Therefore, a 100-mg dose of yohimbe will contain only 3 mg of yohimbine. In research studies, yohimbine is usually administered at a dose of about 0.2 mg/kg of body weight.икони

Supplements are designed to promote fat loss. The term fat loss will be used rather than weight loss because the latter term does not differentiate between muscle mass and fat mass. Supplements designed to promote fat loss can function on one of a number of different principles. These principles as well as the most commonly used fat loss supplements.

Over the last 20 years, there has been about a 10% increase in the prevalence of overweight individuals. Furthermore, one in five adolescents are considered obese, which is a 45% increase Because of societal pressures, it seems that everyone has used or at least has thought of using a fat loss product at one time or another. This includes adolescents as well as older adults. Just because these supplements are sold in health food and vitamin stores does not guarantee their safety. Some of these supplements may have cross-reactivity with some prescription medications and alcoholic beverages.
Increase in Fat Oxidation

Several factors are involved in the use of lipids as fuel. For muscles to oxidize fatty acids, fat (triacylglycerol) must first be mobilized from the adipose tissue. This is referred to as lipolysis. Once the free fatty acids are lysed and released from adipose tissue, they must be transported by albumin in the blood to the muscle, where uptake occurs via a specific transporter protein called the fatty acid binding protein (FABP) When the free fatty acid (FFA) enters the muscle it is activated, after which the activated fatty acid is transported into the mitochondria where Beeta-oxidation occurs.

Theoretically, an increase in fatty acid oxidation could be achieved at anyone of seven sites. However, the mobilization of free fatty acids from the adipose tissue appears to be the best site because the uptake of FFA by the muscle is dependent on the arterial blood concentration of FFA. The more FFA released by the adipose tissue, the higher the concentration of FFA in the circulation. Therefore, any product that increases lipolysis should increase fatty acid oxidation at the muscle.
Mechanism of Action for Fat Loss Supplements

Supplements marketed to promote fat loss can theoretically function on one of a number of principles, from increasing adipose tissue lipolysis or fat breakdown, to suppressing the appetite or the desire for food to reducing the amount of fat absorbed from food during the digestive process. To better understand how fat loss supplements function, their potential mechanisms of action should first be understood.

The bodybuilding supplements guide advices that the eating of the supplements around 21gm for first 5 days moreover 2gm after than for preservation of health. However as the capability of muscle cells are restricted over practice of dose not at all helps. As price is one of the significant factors, for the support of people a few companies bring out their finest bodybuilding supplements with a low cost such that all can pay for to it. It is a big contract to discover a place that makes available a quantity of corporations makes of bodybuilding supplements.

Human Studies

Duffy and Conlee had 11 male subjects ingest 1.24 g of sodium acid phosphate and potassium phosphate 1 hour before exercise (acute) and 3.73 g/day of the phosphate combination for 6 days before exercise (chronic). Tread­mill endurance time, after 15 minutes of recovery from the first exercise, and oxygen uptake during the treadmill exercise, were measured. Running times ranged from 172­183 seconds during the first run and 145-152 seconds during the second run. Oxygen uptake averaged 52 mL/ kg/min during all conditions. The results showed no significant effect of acute or chronic ingestion of a combination of phosphates.

Bredle et al. conducted a double-blind, crossover experiment with 11 male runners. The subjects ingested 176 mmol/day of calcium phosphate or a placebo for 4 days. On day 3, subjects performed an incremental VO2max test on a treadmill, and on day 4, subjects ran on the treadmill at 70% VO2max until exhaustion. On day 4, plasma phosphate levels were significantly higher than in controls, but erythrocyte phosphate, 2,3-DPG, and oxygen half-saturation pressure of hemoglobin were unchanged. Also, neither VO2max nor sub maximal run time to exhaustion was changed by the treatment.

Treatment with phosphate increased the arteriovenous oxygen difference. The authors concluded that phosphates improve some cardiovascular functions, but do not have an effect on aerobic power.

Thirty endurance-trained males were studied for 364 days. Ten control subjects exercised 14.4 km/day at 10,000 steps/day. The other 20 subjects exercised less than 2.9 km/day (3000 walking steps/day) with half of them consuming phosphate, fluid, and salt. The results showed that hyperhydration and phosphate supplementation could minimize phosphate loss in endurance-trained subjects during periods of low exercise routines.

Conversely, when ten well-trained distance runners were given a phosphate load or a placebo for 3 days, the results were different. Pre- and post-measures included plasma phosphate concentration, RBC 2,3-DPG, hematocrit and hemoglobin concentrations, and degree of lactic acidemia. Blood samples for the control condition were drawn before and after a warm-up, after treadmill exercise at a 10% grade, and after the completion of the VO2max determination. Serum phosphate and RBC 2,3-DPG levels were significantly increased after the ingestion of phosphate. Also, VO2max was significantly increased and correlated with the rise in RBC 2,3-DPG .

Next, eight trained cyclists participated in three cycle ergometer tests after consuming phosphate, placebo, or no supplement. time to exhaustion, serum 2,3­DPG, and serum phosphate levels were measured before and after treatment. Serum phosphate levels did not change in any group, but there were increases in 2,3-DPG during phosphate supplementation. There was also a significant difference and time to exhaustion .

Moreover, Krieder et al. had seven male competitive runners participate in a two­session, placebo-controlled, double-blind study on phosphate loading. Oxygen uptake, ventilatory anaerobic thresh-old, and 5-mile performance were randomly tested on day 3 or day 6 after supplementation with tribasic sodium phosphate four times per day for 6 days. Phosphate loading significantly increased resting and post-exercise serum phosphate concentrations and also significantly increased maximum oxygen uptake (4.77-5.18 L/min) and ventilatory anaerobic threshold . Five-mile run times were different between sessions, but not significantly; however, mean performance run oxygen uptake was significantly lower with the ingestion of phosphate.

Two years later, Kreider et al had six male cyclists and triathletes consume 1 g of tribasic sodium phosphate or a glucose placebo four times per day for 3 days before exercise. The exercise consisted of an incremental maximal cycling test or a simulated 40-km time trial on a computerized race simulator. The subjects continued supplementation for 1 extra day, and performed the same exercise again. Metabolic data were collected during 15-second intervals and venous blood samples were collected during each stage of the cycling test and every 8 km during the run. The results showed that the phosphates increased anaerobic threshold, myocardial ejection fraction and fractional shortening, VO2max (69.3 versus 75.4 mL/kg/min for placebo and phosphate groups, respectively).

A fair amount of data have been collected on the use of phosphates as an endurance enhancer. With proposed mechanisms such as increasing oxidative phosphorylation, phosphocreatine synthesis, 2,3-DPG production, and also decreasing blood pH, it would seem plausible that phosphates would increase endurance performance. Currently, the data are mixed, with some studies showing an improvement in endurance performance and others showing no improvement. Phosphates do seem to have some potential as an ergogenic aid, but more studies are needed to prove this.

Green drinks are a sudden cure for maintaining the balance in the stomach when you are upset. For such problems there are specific green drinks that you need to take. Green drink so specifically chosen should be taken before going to bed with water or as specified. The next morning you will be normal and fine after you have an easy bowel movement and the stomach is cleanly flushed.

There are many benefits of taking whey proteins and just will have a glimpse of them. Athletes require as they need proteins in double amount. It has some specific bioactive elements that reduce the cholesterol level and risk of heart problem is reduced. It stabilizes the blood glucose level and helps in stabilizing the weight helping in weight management. It is easily available protein to the body as it is high in protein and is easily absorbed. They also maintain the muscle strength helping in healthy ageing.

Researchers Poortmans and Dellalieux from the Department of Physiological Chemistry, Institute of Physical Education and Kinesiotherapy at Free University in Brussels, Belgium, studied the effects of a high- and medium-protein intake in bodybuilders and other well-trained athletes. Subjects underwent blood and urine sampling in addition to keeping a 7-day record of their food intake. Data demonstrated that despite higher plasma concentrations of uric acid and calcium, the group of bodybuilders on the high-protein diet had normal renal clearance of creatinine, urea, and albumin. Interestingly, the nitrogen balance for both groups became positive when daily protein intake exceeded 1.26 g/kg. Researchers concluded that protein intake under 2.8 g/kg/ day does not impair renal function in well-trained athletes.

Animal data enforce the belief that a high-protein diet does not damage the mammalian kidney. This lack of toxicity is present even at extremely high amounts for prolonged periods of time. Zaragoza and colleagues fed rats a dietary regimen in which protein constituted 80% of their energy intake for more than half of their life span. In spite of the amount of protein and the time of administration, no deleterious effects were noted.

High-protein diets may increase the excretion of calcium, a particular concern to women at risk for osteoporosis. However, work by Orwell and Porter & Johnson suggest that increased protein intake is often beneficial and associated with anabolic processes in bone. In a study published in Calcified Tissue International, Cooper et al. studied bone density (dual-photon absorptiometry in the lumbar spine and proximal femur and single-photon absorptiometry in the distal and mid-radius) in 290 women ranging from 30 to 94 years of age. Dietary information on calcium, phosphorus, vitamin D, protein, fat, and total energy were obtained from a 7-day food record. Among the premenopausal women studied, there was a statistically significant positive association between protein intake and bone mineral content in the distal radius and proximal femur. Postmenopausal women showed no relationship between protein and bone mineral content. From the food record, all of the women studied consumed a mean of 75 g/day of protein.These results suggest that dietary protein consumption may be a determinant of the peak bone mass attained by premenopausal white women. They further commented that the finding of a positive association between protein consumption and bone mineral content was a surprise because animal and human studies on calcium metabolism show excess urinary excretion of the mineral as protein intake increases. According to work by Freudenheim et al., it is possible that the hypercalciuric effect of protein is offset by a hypocalciuric effect of phosphorus, which is present in substantial quantities in diets high in meat protein. In women who engage in strength training, any hypercalciuric effect of protein may be offset by the strong effect this mode of exercise has on increasing bone density. There may be further benefits on bone from a high-protein diet and weight training via increased insulin-like growth factor-1, which has been shown to have a positive effect on bone mass. Levels of this peptide hormone have been shown to increase in strength-trained subjects after a protein-carbohydrate supplement and in those who consume a protein supplement after hip fracture.

Atherogenic effects of high-protein diets have been over­ stated, especially in regards to athletic populations. In the past, strength athletes and football players (especially offensive and defensive linemen) were known for consuming protein sources that were high in saturated fat such as various forms of fast food, whole milk, and fatty cuts of beef. Today, athletes have access to protein sources that contain minimal amounts of fat like chicken breast without skin, fish, lean cuts of beef, and egg whites. Protein supplements available today contain little to no fat. To consider a diet high in protein that is also high in fat is an outdated concept. With the variety of lean, whole-food sources of protein and the multitude of protein supplements available, some athletes may need to be advised to consume additional fat in an effort to get sufficient calories to meet their daily requirement.

Human Studies

One of the first studies conducted on the effects of caffeine and endurance was by Perkins and Williams in 1975 Resting heart rate, submaximal heart rate, maximal heart rate, and ratings of perceived exertion were tested in female subjects before and after a progressive workload to exhaustion on a cycle ergometer. The subjects ingested a placebo, or 4 mg, 7 mg, or 10 mg of caffeine in this double-blind study. There was no significant effect on exercise performance.

Another early study on caffeine was conducted by Costill et al. Nine competitive cyclists exercised until exhaustion on a cycle ergometer at 80% . One trial was conducted 1 hour after the ingestion of decaffeinated coffee and the other after the ingestion of coffee containing 330 mg of caffeine. The trial with caffeine resulted in a longer cycling time compared with the trial without caffeine . Fat oxidation was significantly higher with the use of caffeine and ratings of perceived exertion were significantly lower. The authors concluded that caffeine increased endurance by increasing lipolysis and exerting a positive influence on nerve impulse transmission.

Ivy et al also conducted a study on caffeine and its effects on endurance in the late 1970s. Nine trained cyclists were used in this study The subjects ingested 250 mg of caffeine 1 hour before a 2-hour bout of isokinetic cycling at 80 rpm. The subjects also ingested an additional 250 mg of caffeine at 15-minute intervals during the first 90 minutes of exercise. This significantly increased work production and VO2 by 7.4% and 7.3%, respectively Fat oxidation was also elevated by 31%, therefore, the increase in work production with the ingestion of caffeine was attributed to an enhanced rate of lipid catabolism.

In a recent study by Cohen et al seven competitive road racers performed three, 21-km races in the heat and humidity after randomly ingesting 0, 5, or 9 mg/kg of caffeine. The subjects were allowed to imbibe water at each 5-km interval. They found no improvement in race times for any of the caffeine doses when compared with a placebo.

A study by Wemple et al. also showed no improvements with the use of caffeine. Six subjects performed 3 hours of cycling at 60% . Also, maximal performance was tested at 85% following the 3-hour endurance trial. During exercise, the subjects ingested 35 mL of a carbohydrate electrolyte drink with or without 25 mg/dL of caffeine. At rest, the urinary volume was significantly greater during the caffeine trial (1843 mL) versus the placebo (0411 mL), but during exercise there was no difference in urinary volume (398 versus 490 mL for caffeine and placebo, respectively). Conclusively, this study showed no improvement in endurance performance; however, this study also showed that there is not a risk of dehydration with the ingestion of 25 mg/dL of caffeine.

Conversely, most studies conducted on the use of caffeine have shown positive results on endurance performance. Immediately before exercise, six endurance-trained males, who had previously competed in at least two marathons, ingested 10 mg/kg of caffeine or a placebo? The exercise consisted of running on a treadmill at 75% of their VO2max for 45 minutes, and then increasing the speed by two miles per hour until exhaustion. The caffeine trial resulted in a significant increase in the distance run when compared with the placebo 0.9% increase and control (2.1% increase).

Different dosages of caffeine (0, 5, 9, or 13 mg/kg) were also investigated in nine well-trained cyclists 8 Encapsulated caffeine was administered 1 hour before the subjects cycled at SO% VO2max until exhaustion. A significant increase in endurance performance was noted during all three trials when compared with the placebo but there was not a dose­related response. Also, there was an increase in free fatty acid and glycerol concentrations with the ingestion of caffeine.

The effects of caffeine were investigated at different levels of intensity. Eight untrained males cycled until exhaustion at 10% above or below anaerobic threshold after randomly receiving 5 mg/kg of caffeine or a placebo 60 minutes before exercise. There were no differences between trials when the subjects exercised at 10% above anaerobic threshold; however, ratings of perceived exertion were significantly lower (14.1 versus 16.6 for caffeine and placebo, respectively) and time to exhaustion was significantly higher during the caffeine trial at 10% below anaerobic threshold. This may be because the subjects were untrained.

A study was also conducted on the effects of caffeine in coffee or water. Nine fit, young adults performed five trials after ingesting a capsule of caffeine or placebo with water or coffee (decaffeinated coffee, decaffeinated coffee with caffeine added, or regular coffee). The dosage of caffeine was 4.45 mg/kg with 7.15 mL/kg of solution. After 1 hour of rest, the subjects ran at 85% until exhaustion. Plasma epinephrine was significantly increased with the ingestion of caffeine, and the increase was significantly greater with the capsules when compared with the coffee. Also, endurance performance was only increased during the caffeine capsule trial (7.5- to 10-min increase when compared with the other four trials). The authors speculated that coffee must have a component that moderates the actions of caffeine.

Bell and Jacobs conducted one of the most recent studies done on caffeine. In this field study; nine healthy male recreational runners completed six 3.2-km runs wearing 11 kg of gear (Canadian Forces Warrior Test) after ingesting 325 mg of caffeine and 75 mg of ephedrine. Heart rate was significantly higher in the caffeine and ephedrine trials, and supplementation significantly improved the subjects’ time when compared with a control and placebo trial .

The plethora of data clearly show that there are potential benefits of consuming caffeine before an endurance event. This central nervous system stimulator can increase the release of catecholamines and increase the use of free fatty acids for energy. Dosages as low as 330 mg 1 hour before exercise have been shown to increase an individual’s performance time.

Safety and Toxicity

Moderate to high doses of caffeine can result in nervousness, restlessness, insomnia, and tremors. Caffeine is also a diuretic, which might increase the risk of dehydration and heat-related illness. Caffeine can be addictive and result in severe headaches, fatigue, irritability, and gastrointestinal distress after withdrawal from the substance. In addition, individual differences in caffeine sensitivity may account for the lack of an ergogenic effect.

Also, regarding competitive sports, the International Olympic Committee only permits 12 µg/mL of caffeine in the urine. This is the equivalent of consuming 600 to 800 mg of caffeine within 30 minutes .