Browse > Home / Plans / What Are the Energy Sources For Cyclists

What Are the Energy Sources For Cyclists

There are three energy sources for cyclists. Fat, carbohydrates and protein provide you with energy. Glycogen is the energy source of choice.

There are three energy sources

The energy sources for cyclists comes from three sources. These three sources are fat, carbohydrates and protein. The fat energy comes through the bloodstream provided by adipose tissue or from the intestines out of the foods you consume. Your fat energy can also be supplied by stored fat in your muscle tissue. Carbohydrate energy is supplied by the liver from your stored glycogen, amino acids that are metabolized, from carbohydrates that have been absorbed by your intestines or from the glycogen stored in your muscle tissue.

Fruit Bars

In addition your muscles store around 2500 calories of fat intramuscularly in muscle cells and more than 1500 calories of glycogen. The smallest source of energy is protein. When your fat and carbohydrate energy supply is sufficient only about 5% of your energy is supplied by protein. If there is not sufficient supplies of fat and carbohydrate energy as much as 15% of your energy sources can come from protein.

Heart rate and activity levels

Your heart rate corresponds to you activity level as follows:
Low activity level = 65% of maximum heart rate
Moderate activity level= 75% of maximum heart rate
Maximum activity level = 90% of maximum heart rate

Carbohydrates are metabolized on the basis of your respiratory exchange ratios which were Traditionally believed to be at a much higher rate than they now are believed to be. This ratio is determined by the relative concentrations of the carbon dioxide and oxygen that are expired.

Electrolyte Drink

The newest techniques of calculating this ratio suggest that the fat contribution is greater than anyone had previously been able to determine. Most recent studies show a rate of 85% of your energy is provided by fat at low intensity exercise levels. About half from fat at moderate levels and at high exercise levels about 70% of the energy provided comes from carbohydrates.

Where does your energy come from

Fat from the bloodstream supplies most of your energy at low activity levels and at higher activity levels your fat calories come from fat that is stored in muscle tissue. As your activity level rises fat contributes more absolute energy but less relative. Triglycerides or intramuscular fat energy supplies less than one-third of your energy as that of the glycogen stored in your muscles at a moderate activity level.

At a high activity level the absolute fat contribution dwindles to almost nothing as the stored glycogens take over. Blood fat and glucose levels are contributors to muscle energy supplies even when your activity level is high, but compared to glycogens the contribution levels of fat and glucose are quite limited. If glucose is consumed then the glucose contribution will rise. It is futile to consume fat for energy contribution since the absorption rate is lengthy.

Consume carbohydrates

About 250 calories per hour of consumed carbohydrates may be a factor in muscle energy. If you consume carbohydrates for energy it will reserve your stored levels of glycogen in your muscles. This consumption of carbohydrates will allow your activity level to increase and prolong it for a greater period.

Fruit


As the stored glycogen in your body is used up you cannot continue with the same exercise intensity so the relative contribution of fats and proteins rises to help your energy output. As your glycogen stored is depleted fat metabolism also decreases and muscle protein begins to be broke down, metabolized by your liver and given back to your muscles as blood sugar.

Glycogen is the fuel of choice

Although, training can increase the use of muscle fat for energy and the rate for which the body uses the fat in the bloodstream at a given activity level at high activity levels glycogen is the fuel of choice for the body.

Written by Sam · Filed Under Plans