Metabolism is the basic process in our body that includes all the chemical reactions necessary for sustaining life.
It involves converting food into energy, synthesizing molecules needed for cellular functions, and eliminating waste products.
Understanding the principles of metabolism is key to understanding how our bodies work and how physical activity and training can affect this complex process.
Metabolism can be broadly divided into two categories: catabolism and anabolism.
Catabolism refers to the breakdown of complex molecules into simpler substances, releasing the energy of the process.
Anabolism, on the other hand, involves the synthesis of complex molecules from simpler substances, which require energy input.
One of the primary roles of metabolism is to create energy.
The energy currency in our bodies is adenosine triphosphate (ATP).
Through the process of cellular respiration, the macronutrients (carbohydrates, fats and proteins) we consume are broken down, and their energy is stored in ATP molecules. This energy is then used for various activities, including muscle contraction, maintaining body temperature, and even simple tasks such as breathing and digestion.
Metabolism works through interconnected pathways, each enabled and facilitated by specific enzymes.
These pathways include glycolysis, the citric acid cycle (or Krebs cycle), and oxidative phosphorylation.
Glycolysis breaks down glucose to produce ATP and pyruvate, while the citric acid cycle further breaks down pyruvate to make additional ATP.
Oxidative phosphorylation occurs within the mitochondria and uses the electron transport chains to produce a significant amount of ATP.
Physical activity and exercise can significantly affect the metabolic processes in our bodies.
Regular training causes adaptations that improve metabolic efficiency and improve overall health.
Engaging in physical activity increases the body’s demand for energy, which leads to an increased metabolic rate.
Aerobic exercise and strength training also contribute to an increase in basal metabolic rate (BMR), which refers to the energy expenditure required to maintain vital body functions at rest.
This elevated BMR can lead to increased calorie burning even during periods of inactivity.
Strength and resistance exercises promote skeletal muscle growth and development.
Because muscle tissue is metabolically more active than fat tissue, increasing muscle mass can increase resting metabolic rate (RMR).
This means that people with more muscle mass burn more calories at rest, contributing to long-term weight management.
Physical activity can affect the use of different energy substrates during exercise.
During low-intensity activity, such as walking, the body relies predominantly on stored fat as a fuel source. However, as intensity increases, the body relies more and more on glycogen, the stored form of glucose in the muscles and liver.
Regular training can improve the body’s ability to mobilize and use these energy substrates more efficiently.
One fascinating aspect of metabolism is the phenomenon known as excess post-exercise oxygen consumption (EPOC).
After intense exercise, the body needs additional oxygen to restore physiological and metabolic balance.
This increased oxygen consumption results in continued calorie burning even after the exercise session is over, contributing to overall energy expenditure.
When all this is taken into account, the inseparable connection between metabolism and regular physical activity cannot be ignored!