Having enough energy in sport is usually the difference between being successful and not. Athletes must have a high level of stamina and endurance as well. There are lots of different supplements that have a purpose of supplying the extra energy to complete certain exercises.
 

Largely, because the body uses Glucose as a primary energy source, a large number of the supplements contain this vital ingredient. Glucose is a sugar that if not consumed in its purest form, can be obtained from Carbohydrates.
 

Carbohydrates are naturally made up of Carbon, Hydrogen and Oxygen molecules and are classed as Monosaccharides, Disaccharides and Polysaccharides. Commonly, energy related supplements contain Fructose, Glucose or Dextrose and Galactose. This is because they are all Monosaccharides and as they are only one unit, they can be easily digested and used within the body. Other products use Disaccharides and Polysaccharides which are longer chains of Monosaccharide sugars joined together. Polysaccharide’s such as the man made Maltodextrin is effective because it is harder to break down within the body, and therefore provides a slower, but more constant supply of energy. Different carbohydrates have different speeds in which they are broken down to simple sugars to there simplest form to provide energy. The time this takes is normally gauged by the Glycemic Index (GI). Foods or supplements with a lower GI normally take longer to break down and diffuse into the bloodstream. These particular carbohydrates provide a slower, but more fluent supply of glucose or energy. Monosaccharide carbohydrates normally have a much higher GI, because of the simplicity of the sugar; they are much easier to breakdown. These sugars supply high quality energy but supplies become exhausted rapidly. A simple sugar such as Glucose will have the GI of 100, the maximum. A polysaccharide sugar is more likely to range between 55 and less.
 

To produce energy during exercise the body uses a variety of different energy systems depending on the duration of the exercise. If the activity is short and explosive the body naturally uses its Alactic Anaerobic energy pathway also known as the ATP/ PCr System. This system uses energy from substances known as ATP or Adenosine Tri Phosphate and Phospho-Creatine. In this system ATP, which is stored in muscle is broken down to ADP or Adenosine Di Phosphate leaving a single Phosphate and producing Energy. It is the quickest method of obtaining energy, but unfortunately these ATP stores can only last up to 2 seconds. Phospho Creatine is then used in the resynthesis of ATP. The only problem with this is that Creatine also runs out fast, normally after approximately 4 to 6 seconds. This provides around 5 to 8 seconds of ATP production.
 

If the exercise is longer than this period, the Creatine stores are not given a chance to replenish and therefore the body is unable to function at a high intensity for very long.
 

After this period of activity, and for longer activities the body resorts to stored glucose for ATP. Following the ATP/ PCr system, the body uses a system known as the Lactic Anaerobic energy system. This system enables the body to produce energy without the use of oxygen. This however comes at a price. The breakdown of glucose results in the production of lactate and hydrogen ions. The accumulation of these products results in the production of lactic acid which can inhibit muscle activity.
 

The energy from the anaerobic energy system provides energy for short but high intensity activities lasting for no more than several minutes in duration before the lactate threshold (the point at which lactic acid kicks in) inhibits this system.
 

For activities longer than a couple of minutes the body uses the Aerobic energy pathway. This pathway involves oxygen so the lactate threshold is prolonged. This system is normally used in lower intensities but is effective in fuelling the body for long periods of exercise. This particular system uses all the body’s glycogen stores, fat and even protein storages if necessary. Only a lack of fuel will result in the end of exercise. Many endurance athletes commonly refer to this depletion of all energy stores to ‘hitting the wall’.
 

As with the other energy systems, the aerobic energy system uses ATP to produce energy. Nutrients consumed within a diet get converted to ATP based upon the intensity and duration of activity. Usually, carbohydrates are the popular choice as a fuel for energy as they are easier to break down into simple sugars like glucose to be used with ATP. Fats are a great fuel for endurance events as they produce a higher energy yield than both carbohydrates and protein’s. The only problem is they do take longer to be converted to energy. Fat storages can last for large lengths of activity just as long as oxygen is present within the equation to although fat metabolism.
 

Carbohydrate stores can normally fuel the body with energy for up to two hours of exercise. After this period, glycogen depletion occurs and athletes will be unable to compete at such high intensities. Slower intensities will make sure that the body uses fats to fuel the activity.
 

Carbohydrates can effectively produce up to 38 molecules of ATP when metabolised in the presence of oxygen, with free fatty acids producing at least 140 units of ATP.
 

In extreme cases the body can use Protein as a source of energy, but this is only necessary if both fat and carbohydrate stores are completely depleted. If this is the case, protein, which is normally used for muscle repair and growth, will be converted to produce energy, with a negative effect on muscle size.