EXERCISE: The Effect On The Body

Exercise When we exercise, our body must make a range of short term changes in order to keep up with the physical demands of the activity. It does this in a variety of ways across the: Muscles Lungs Heart Energy Systems.

Energy Production In order for muscles to function they require energy to do so. As a muscle contracts, ATP provides the energy for this.

Energy Production Unfortunately there is only enough ATP in the muscles to last for 2 seconds. Because ATP is the only energy source used directly for this, our body has 3 other ways of regenerating this chemical to create energy.

ATP-CP System This system uses creatine phosphate (a high-energy molecule stored in muscles) to regenerate ADP back to ATP. CP ADP ATP Creatine

Glucose (from glycogen breakdown or delivered from oxygen Anaerobic System This system uses glucose from the blood and glycogen stored in the muscles to regenerate ADP back to ATP. Glucose (from glycogen breakdown or delivered from oxygen O2 Chemical Reaction ATP Released to blood Lactic Acid

Aerobic System Aerobic respiration takes place in the mitochondria. It requires oxygen and a series of chemical reactions to produce ATP. Mitochondria: Our cell’s power producers which convert energy into forms that can be used.

Aerobic System This system uses glucose from the blood, glycogen stored in the muscles as well as fatty and amino acids to generate ATP. Glucose (from glycogen breakdown or delivered from oxygen Fatty Acids Pyruvic Acid Amino Acids Aerobic Respiration in Mitochondria ATP CO2 O2

The Heart When exercising the main change that will occur with the heart is an increased cardiac output. This occurs for 2 main reasons. 1- The amount of oxygen needed by working muscles increases 2- The amount of waste products (CO2 and Lactic Acid) from the muscles increases

The Lungs When exercising the main change that will occur with the lungs is increased breathing rate and respiratory volume. This occurs for 2 main reasons. 1- The amount of oxygen needed by working muscles increases 2- The amount of waste products (CO2) from the muscles increases

The Muscles The muscles have a number of things that occur during exercise: Energy production (3 types) Depleted energy stores to do this (especially carbohydrates and some amount of fats) Increased lactic acid build up contributes to muscle fatigue and is partially responsible for muscle soreness from intense activity.

The Muscles Heat Production Only about 40% of the energy released during muscle contraction is converted to useful work. The rest is given off as heat to maintain constant temperature within the body. This is done through sweating and radiation of heat from the skins surface.

Adaptations The Heart and Circulatory System Cardiac Muscle gets bigger increasing heart volumes Red Blood cells increase transporting more O2 Capillary beds increase creating better gaseous exchange Resting Heart Rate Decreases Accumulation of Lactic Acid decreases due to more efficient circulatory system

Adaptations The Lungs Diaphragm increases in strength Greater respiratory volumes Increase in diameter of capillaries on alveoli leads to increased gaseous exchange

Adaptations The Muscles More mitochondria Muscles, bones, ligaments become stronger Myoglobin numbers increase allowing more 02 stored in muscles Store more glycogen Enzymes for energy production become more concentrated and efficient