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laggente se ne sta nel letto invece di romb 'u CAXX in giro, traduco...
http://www.racerxvt.com/article/how-caf ... erformanceWith all of the caffeine-laden products on the store shelves and in our hands, I believe educating ourselves regarding the effects of these products is important. Do you ever stop to think...What is caffeine? And...how does it affect my body, my performance, and my children? Or, should I be drinking it on race day...or even at all? This article will answer those questions.
What is caffeine?
Caffeine is one of a group of compounds called methylxanthines, which occur naturally in over 60 species of plants, including coffee beans, cocoa beans, cola nuts and tea leaves. It is naturally present in coffee, tea, cola soft drinks, cocoa and chocolate, and is added to many products we consume. Energy drinks and caffeinated waters are the most recent additions to caffeinated products we use. Caffeine is also found in combination with drugs used as stimulants, cold remedies, pain remedies, diuretics and weight control products.
How does it affect my body?
Caffeine stimulates the central nervous system and can produce many effects in the body. It typically increases metabolic rate, heart rate, rate of urine production. In may also improve performance and mood, help relieve headache pain, enhance alertness and reduce fatigue.
Caffeine may have detrimental effects as well as it is both psychologically and physically addictive. High levels of consumption have been linked to nervousness, irritability, anxiety, insomnia, headaches, abnormal heart rhythms and stomach upset. It may also increase the number and frequency of bowel movements. Because caffeine is a diuretic (draws water to the kidneys), chronic and/or excessive use is associated with dehydration. In addition, caffeine use may cause calcium to be pulled from bones, which may lead to bone loss and osteoporosis. This is an especially important consideration for children whose bones are still developing and require adequate amounts of calcium to do so.
Consumed in moderation (approximately 250 mg per day), caffeine appears to be safe for most people (see chart below for amounts of caffeine in several foods and drinks). Humans do adapt to its usage, so regular and frequent consumption leads to a reduced effect. In other words, you may need higher amounts to achieve the same effect. Children should limit their intake to 100 mg per day.
Always consult your physician before taking any supplement or beginning an exercise or nutrition program.
How will it affect my riding and racing? Several studies have shown caffeine to have an ergogenic effect, which means it enhances sport performance. These studies have concluded that caffeine consumption increased the free fatty acid (FFA) concentration in the blood. The increased FFA availability enhances the body's ability to use these fats as fuel during endurance activities. Using the FFA's for fuel spares muscle glycogen, the energy "reserve" contained within muscle. This would prolong endurance in sporting events. Caffeine has also been shown to increase the force of muscle contractions, which would enhance strength for a short time. Caffeine can also make exercise seem easier by decreasing the perception of fatigue.
Although caffeine is capable of improving sport performance it can also be the cause of decreased performance. It may cause nervousness, trembling, anxiety, heart palpitations, muscle tightness, muscle cramping, dehydration and stomach upset. Any or all of the above will likely have detrimental effects on your racing performance.
Will it Reduce Arm Pump?
As stated above, caffeine use increases your risk of dehydration. Losing even small amounts of water from the body will impair performance and lead to poor race results. Becoming dehydrated will cause rider fatigue, which will likely cause or worsen arm pump. The only way to avoid arm pump caused by dehydration is to remain well hydrated. Do this by drinking plenty of water or sport drinks and minimize caffeine use.
How Should I Use It?
A safe method of experimenting to determine whether caffeine is a good supplement for you would be to consume 2 to 2.5 milligrams per pound of body weight one hour before exercise. For example, a 150 pound man would consume 300 to 375 milligrams. This amount should enhance performance without producing a significant number of side effects.
Keep in mind that other ingredients in foods and drinks may change the way the caffeine affects you alone. Most "energy drinks" have high amounts of sugar and several other ingredients which will all determine how that particular drink affects you. Using caffeine pills like Vivarin or No-Doz will allow you to determine the effects of caffeine without the interaction of other ingredients.
Bottom Line: Recommendations for the MX Athlete
Due to the fact that each person reacts differently to caffeine, as a dietitian, I do not recommend taking caffeine as a way of enhancing sport performance in motocross. A better way of improving your performance on the track is through proper training, nutrition and hydration coupled with plenty of rest. If your performance needs improvement, a thorough review of your current training and nutrition program should be done.
If you do choose to use caffeine during exercise or racing, remember this; there are many variables influencing the effect that caffeine has on the body and there is no way to tell when and if those effects will be felt. Each person will react differently. Even the amount of time you take to consume a caffeinated drink, or the length of time before an activity you take a pill, will change the way you are affected. Also, there is no way to determine when the caffeine will be gone. Therefore you stand the chance of your energy level crashing when you need energy the most . Because of these factors, caffeine use needs to be done intelligently and with caution.
Hydration is a very important factor in training and racing performance and needs to be a priority every day. As a dietitian I feel that soft drinks like Coke or Pepsi, and "energy drinks" are certainly not the best choice for staying hydrated. I would not recommend these types of drinks for the serious athlete or for anyone on race day. Water and sport drinks are always a better choice. If you feel you must consume energy drinks, use them as a recreational drink not as a performance enhancer or for re-hydrating.
Before using caffeine on race day, make sure that you have used caffeine extensively under a variety of training conditions and are thoroughly familiar with how your body reacts to this substance. Never try anything new on race day.
Using Caffeine in MX: Quick Facts
Pros
may increase endurance
may increase strength of muscle contraction
may enhance alertness
makes exercise seem easier
may decrease arm pump
Cons
may cause stomach upset, dehydration, nervousness and many other side effects
may increase arm pump due to fatigue caused by dehydration
no way to determine when and if effects will be felt and when they will end
may need to continually increase dosage to feel effects
many variables determine how and if caffeine will have an effect
may require rider to make more trips to the restroom at inconvenient times due to increased urine production along with number and frequency of bowel movement
How to Use
2 to 2.5 milligrams per pound, one hour before exercising, riding, racing
300-375mg for a 150 pound person
use Vivarin or No-Doz tablets to eliminate effects of other ingredients
experiment before race day!
experiment under a variety of conditions and be familiar with how it affects you
stay well hydrated
) 8 -9 ore al giorna.non mi faccio mancare 4-5 lt al giorno di acqua.
, ne servirebbe un po' anche a me....a dire la verità erano i 4-5 litri d' acqua che mi avevano insospettito 
!!! mia sorella ha analizzato 1 lattina di Redbull.... rilascia caffeina ed altre sostanze nocive pari a circa 7 caffè.... fate voi...