It is the ability to race or to take part in a sporting event that involves long distances or that demands great physical stamina.
Muscular fitness consists of muscle strength, power, and endurance. Muscle endurance allows muscles to undergo repeated contraction for extended periods of time while resisting fatigue. Cardiovascular endurance allows maintenance of a stable heart rate during prolonged exercise such as running, swimming and cycling by sustaining efficient energy production in muscles. Both muscular and cardiovascular endurance can be gained through training.
Fatigue occurs in different ways, depending on nutrient and oxygen availability. Muscle cells use carbohydrates, lipids and oxygen to create energy (in the form of the molecule, ATP). Cells convert nutrients into energy (ATP) by a process known as respiration. Respiration occurs in a cellular organelle called the mitochondria – the powerhouse of the cell. The byproducts of respiration include lactic acid and reactive oxygen species, both of which contribute to muscle fatigue.
The impact of nutrient usage on muscles:
• When lipids and carbohydrates are used as fuel in the presence of oxygen, the process is called aerobic respiration. Lipids are a more efficient source of energy since more ATP is produced from one lipid molecule than from one carbohydrate molecule (glucose). However, aerobic respiration contributes to production of ROS byproducts.
• Using lipids as fuel requires oxygen. So, when oxygen is in short supply, the cells switch to a different process of carbohydrate breakdown, called anaerobic respiration. Anaerobic respiration is a less efficient form of energy production and it leads to a buildup of lactic acid, resulting in muscle fatigue during exercise.
• Increasing lipid usage makes energy production more efficient and can help combat lactic acid buildup.
Reactive Oxygen Species (ROS) are free radical byproducts of aerobic respiration, which cause ‘oxidative stress’ when present in excess.
• If left unchecked, excess ROS can damage proteins, lipids, and DNA – especially those found in the mitochondria, where ROS are made.
• Antioxidants neutralize ROS and protect mitochondria from ROS damage, which allows muscles to continue producing energy during prolonged physical activity.
While carbohydrates and lipids from food ensure that there is enough fuel for energy production, antioxidants help neutralize ROS to dampen their negative effects on muscle cells.
• Carbohydrates burn the fastest, which makes them the first choice for fueling energy production. However, using only carbohydrates, leads to lactic acid build up and fatigue.
• Natural astaxanthin , helps improve lipid utilization during exercise by protecting mitochondria from ROS, including the mitochondrial proteins required for metabolizing fat. For example, mitochondria have a fat transporter, called CPT I. This transporter is susceptible to damage from ROS as they build up during exercise. This results losing the ability to bring fat into the mitochondria. By protecting this fat transporter from exercised-induced ROS, natural astaxanthin preserves our ability to use fat for energy, even during prolonged exercise. This lowers dependence on carbohydrates for fuel, which results in less lactic acid build up, less fatigue, and better endurance.
For sports requiring extended periods of exertion, endurance is more important than power and strength. Muscle cells need energy and antioxidants to keep going. Natural astaxanthin is nature’s most powerful antioxidant, and it picks up the slack when our body’s own antioxidants can’t keep up with the pace of ROS production during exercise.
• Carnitine palmitoyltransferase (CPT I) is a mitochondrial fatty acid transporter that allows mitochondria to take up and use fat to fuel energy production.
• ROS generated during exercise oxidizes CPT I, and this slows down energy production from lipids.
• Natural Astaxanthin prevents ROS damage to CPT I, promoting continued lipid utilization and reducing dependence on carbohydrates, which reduces lactic acid build up hence promoting endurance.
1) 21 cyclists of ages 18 to 39 with Astaxanthin 4 mg/day were tested for VOmax, a 2 hr constant pre-exhaustion ride followed by 20km timed trial. Cyclists supplementing with AstaReal® Astaxanthin experienced an average 2 min improvement (5%) in the time necessary to complete the 20km timed trial, which was accompanied by a 20W increase (15%) in the average power output. In contrast, the placebo group experienced a 19 sec (0.8%) improvement in time and a 1.6W (0.5%) improvement in power output.
2) 16 distance runners belonging to Field and Track Athletic University team supplemented with AstaReal® Astaxanthin 6mg/day were tested for serum lactic acid levels. Serum lactic acid levels after 2 min of exercise were significantly reduced compared to the placebo group (p<0.05).
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