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24 years
Dr. zakia does sweating during cardio workouts brings out also the fat from the cells? what is the components of sweat.
Aug 5, 2014

Dr. Zakia Dimassi Pediatrics
I'm going to define body fat and try to illustrate to to you how the body produces energy with exercise, so that the full picture becomes clear in your mind regarding burning fat and sweating, which are not the same, as sweating (sweat is made up of water, urea, and other minerals -that's why it's salty) indicates an increase in the cellular metabolic activities, but it does not necessarily imply that only fat is being used up - because it could very well be that other sources of energy in the body, like sugar (glucose) or proteins are being utilized.
Fats (also referred to as lipids) in the body are divided into two groups: storage fat and structural fat. Storage fat provides a reserve storehouse of fuel for the body, while the structural fats are part of the essential structure of the cells, occurring in cell membranes and intracellular organelles. Cholesterol is a lipid present in all cell membranes. It has an important role in fat transport and is the precursor from which bile and sex hormones are made.
To fuel its activities, including organ functions (like circulation and respiration), the body relies on 3 energy-producing systems:
- The ATP-PCr (adenosine triphosphate-phosphocreatinine) system:
can use only adenosine triphosphate (It is often called the "molecular unit of currency" of intracellular energy transfer.[1] ATP transports chemical energy within cells for metabolism. It is one of the end products of photophosphorylation, cellular respiration, and fermentation and used by enzymes and structural proteins in many cellular processes) and phosphocreatine (also known as creatine phosphate (CP) or PCr (Pcr), is a phosphorylated creatine molecule that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle and the brain), but these energy sources are in short supply and need to be replaced by the other two energy systems< which are the lactic acid and the oxygen system.
- The lactic acid system:
uses only carbohydrate, primarily the muscle glycogen stores (sugar is stored as glycogen in muscles). At high-intensity exercise levels that may be sustained for 1–2 minutes or less, carbohydrates will supply over 95% of the energy. However, the accumulation of lactic acid may cause the early onset of fatigue.
- The oxygen system:
can use a variety of different energy sources, including protein, although carbohydrate
and fat are the primary ones. The carbohydrate is found as muscle glycogen, liver glycogen, and blood glucose. The fats are stored primarily as triglycerides in the muscle and adipose cells. The absolute work rate determines the total quantity of fuel required, while relative exercise intensity plays a major role in determining the proportions of carbohydrate and fat burned by the working muscles. As one does mild to moderate exercise, blood glucose and fat may provide much of the needed energy. However, the transfer of glucose and fat from the vascular system to the muscles becomes limited, and you soon begin to rely more on your intramuscular stores of glycogen and triglycerides. As you continue to increase your speed or intensity, you begin to rely more and more on carbohydrate as an energy source. Apparently the biochemical processes for fat metabolism are too slow to meet the increased need for faster production of ATP, and carbohydrate utilization increases. The major source of this carbohydrate is muscle glycogen. As such, there will be transition from use of fat to carbohydrate as the primary fuel source during increasing intensity of exercise.
In long-duration exercise, like marathon running, when your body almost runs out of carbohydrate, the primary energy source shifts to fat stores, to the extent that in n the later stages of ultra-marathoning events, fat may become the only fuel available. However, protein as well may become an important energy source in these circumstances. Other than exercise intensity and duration, a number of different factors are known to influence the availability and use of human energy sources during exercise. Gender, hormones, state of training, composition of the diet, time of eating prior to competition, nutritional status, nutrient intake during exercise, environmental temperature, and drugs are some of the more important considerations. For example, warm environmental temperatures may increase the use of carbohydrates, whereas caffeine may facilitate the use of fats.
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