Don't forget to breathe...
A vital requirement of all living animals is a continuous supply of oxygen to provide energy. As cells use oxygen they produce carbon dioxide and dangerous free radicals, waste products that the body must eliminate. This is achieved through the four steps of respiration:
ATP = ENERGY
The cells of the body require energy for self-repair, upkeep and maintenance, and for sustaining their specific functions. This energy is created from the hydrolysis (breakdown) of adenosine triphosphate (ATP). The cellular reservoir of ATP and other high-energy phosphates provides a renewable energy supply. The supply of ATP is maintained through a process called oxidative phosphorylation, which occurs in a part of the cell called the mitochondria, which can be likened to a powerhouse. This process consumes oxygen in proportion to the rate of ATP utilization by the cells. Hence, increases in metabolic activity (i.e. exercise) are associated with increases in the rate of oxygen utilization.
How do we monitor oxygen?
Example: Higher altitudes for greater fortitudes
Perhaps you have heard of athletes training at high altitudes to increase their stamina. Less oxygen is available at high altitudes, which triggers the release of EPO, production of red blood cells and thus a greater amount of haemoglobin. The net result is a greater oxygen carrying capacity and therefore oxygen availability for muscles, thus longer stamina, endurance and overall performance.
From the chemical to the physical
The most miraculous functional characteristic of muscles is their ability to transform chemical energy (ATP) into direct mechanical energy (muscle contraction).
Muscles can contract only if there is sufficient ATP and calcium (Ca2+). A huge amount of ATP is required to pump Ca2+ into muscle cells for muscle contraction. The ATP present in muscle cells at any given time is enough to power contraction for only a few seconds, therefore to keep muscles working past this point, muscle fibres must first produce more ATP (energy).
In order to make ATP, a complex series of reactions must take place, which may be in anaerobic (without oxygen) or aerobic (with oxygen) conditions.
ATP is made through a process known as glycolysis, that breaks sugar molecules into two pyruvate molecules and aids in the release of ATP. As the electrons/energy are shuttled along with ATP, they must be picked up by a special electron carriers known as (NAD). What happens next depends on whether oxygen is available or not.
Why do we get tired?
Fatigue and lactic acid
As we exercise, our breathing becomes faster and deeper in order to deliver more oxygen to our muscles. Although the body prefers to generate most of its energy under aerobic respiration, in some situations (such as the 200m sprint) large amounts of energy are required at a faster rate than the heart and lungs can deliver oxygen.
This is where anaerobic respiration comes into play. The temporary conversion of pyruvate into lactic acid allows energy production to continue for the extended activity period. The working muscle cells can continue this type of anaerobic energy production at high rates for one to three minutes, during which time lactic acid can accumulate to high levels. Lactic acid can interfere with cell function leading to muscular fatigue and the burning sensation felt in exertion. Though it may seem counterproductive, this is a natural defence mechanism as it prevents permanent damage during extreme exercise.
It is popular belief that lactic acid is also the culprit for the muscle soreness you feel in the days following strenuous exercise. However, recent studies have suggested it is the swelling in the muscles that results from an influx of white blood cells, prostaglandins (inflammatory molecules) and other fluids that flow into the muscles to repair the damage or microscopic tears in the muscle fibers.
Fatigue and reactive oxygen species
We’ve all experienced tiredness after going out for a jog, playing competitive sport, or just taking part in recreational exercise. Strenuous exercise and activities that promote intense oxygen demand and muscle contractions also trigger the release of reactive oxygen species (ROS). These differ from “normal” oxygen molecules in that they are highly unstable and react with anything they contact. When they contact cells or DNA, the reaction can be damaging to the point of cell death or DNA mutations.
Generation of reactive oxygen species (ROS) is a normal process in the life of aerobic organisms. The body has evolved systems to remove ROS, termed antioxidants. The term antioxidant can be defined as any substance that delays, shields, mitigates, neutralizes or prevents oxidative damage from reactive oxygen species. These include certain vitamins, protein and non-protein thiols and enzymes.
Since the antioxidant reserve capacity in most tissues is minimal, strenuous exercise with the resultant production of ROS presents a challenge to the antioxidant systems in your body. An acute bout of exercise at sufficient intensity has been shown to stimulate activities of antioxidant enzymes. This could be considered as a defensive mechanism of the cell under oxidative stress. However prolonged heavy exercise may cause a transient reduction of vitamin E and a change in glutathione (GSH) levels in various body tissues, both of which are crucial antioxidants. Recent research suggests that supplementation with certain antioxidant nutrients are necessary for physically active individuals.
Get the facts!
Dr Sport Mechanism of Action
Regular physical exercise has many health benefits such as reduced risk of cardiovascular disease, obesity, diabetes and cancer. While exercise is important, so too is performance! Our beverage is best consumed 30 minutes before exercise, to provide an essential blend of ingredients that support muscle contractions, intracellular energy production (ATP), and a contingent blend of antioxidants to help neutralize the build up of reactive oxygen species linked to the cause of fatigue. While this beverage concludes with a blend of electrolytes for hydration and magnesium to assist with cramps, our last gift to you is recovery, so you can train with the same intensity tomorrow as you did today.