Endurance Physiology & Adaptations: Oxygen, pH, and Buffer Systems

What physiological adaptation occurs in endurance athletes that affects resting heart rate?

Lower resting heart rate due to increased stroke volume.

How does increased stroke volume benefit endurance athletes?

It allows more blood to be pumped per heartbeat, increasing overall blood flow.

What is the difference in oxygen utilization between trained and untrained individuals during exercise?

Trained individuals can strip blood of oxygen more efficiently, leading to lower venous return oxygen levels.

What condition can occur in elite athletes due to efficient oxygen utilization?

Hypoxemia, where the lungs do not have enough time to re-oxygenate the blood.

Where is myoglobin found and what is its function?

Myoglobin is found in muscle tissue and has a high affinity for oxygen, helping to store oxygen in muscles.

What percentage of oxygen is typically present in the atmosphere at any altitude?

21% oxygen, regardless of altitude.

Why does it become harder to perform physical activities at higher altitudes?

The partial pressure of oxygen decreases, making it harder for oxygen to enter the lungs.

What are the three main ways CO2 is absorbed into the bloodstream?

1. Dissolved in plasma, 2. Bound to hemoglobin, 3. Converted to bicarbonate.

What is the most common method for CO2 transport in the blood?

About 70% of CO2 is transported as bicarbonate.

What role do the internal and external intercostal muscles play in respiration?

External intercostals are used for inspiration, while internal intercostals are used for expiration.

What is the significance of pH in the human body?

The body maintains a pH around 7.4, which is crucial for metabolic processes.

How does a change in pH affect acidity or basicity?

A change of 1 in pH represents a tenfold increase in acidity or basicity.

What is lactic acid and how does it relate to exercise?

Lactic acid is produced during anaerobic metabolism and contributes to muscle fatigue.

What is the misconception about alkaline water?

People believe it neutralizes body acidity, but it does not affect stomach acid and is often just more expensive water.

What happens to oxygen levels in the blood of trained athletes during intense exercise?

They can deplete oxygen levels significantly, leading to lower venous return oxygen content.

What is the role of the diaphragm in respiration?

The diaphragm is the primary muscle used for breathing, allowing for efficient expansion of the lungs.

What anatomical structures are the sternocleidomastoid and intercostal muscles associated with?

The sternocleidomastoid is in the neck, while intercostals are located between the ribs.

What is the relationship between exercise intensity and CO2 transport?

Higher exercise intensity increases CO2 production, leading to more CO2 binding to hemoglobin.

What happens to oxygen in the muscles during recovery after exercise?

Myoglobin helps store oxygen, ensuring muscles have access to it even during recovery.

How does the body regulate its pH level?

The body uses buffers and respiratory control to maintain a stable pH around 7.4.

What is the significance of stroke volume in endurance sports?

Increased stroke volume enhances the heart's efficiency, allowing for better oxygen delivery during exercise.

What is the effect of altitude on oxygen delivery to the body?

At higher altitudes, the lower air pressure reduces the effectiveness of oxygen delivery to the lungs.

What is the primary function of bicarbonate in the bloodstream?

Bicarbonate helps transport CO2 from tissues to the lungs for exhalation.

What is metabolic acidosis?

A condition characterized by an excess of hydrogen ions in the body, leading to a lower pH.

What causes lactic acid buildup during exercise?

The rapid burning of carbohydrates, which produces lactate and hydrogen ions.

What role does carbon dioxide play in muscle acidity?

Carbon dioxide is produced during metabolism and contributes to acidity, lowering the pH in skeletal muscles.

What is the primary energy source for glycolysis?

Carbohydrates.

What is the relationship between hydrogen ions and exercise intensity?

Higher exercise intensity leads to increased hydrogen ion production, contributing to metabolic acidosis.

What is the effect of lactic acid on muscle performance?

Lactic acid can disrupt cross-bridge cycling in muscles, reducing their ability to contract effectively.

What is metabolic alkalosis?

A condition where the body becomes too basic, often due to excessive loss of carbon dioxide or intake of alkaline substances.

What physiological process can lead to metabolic alkalosis?

Improper breathing that results in excessive loss of carbon dioxide.

How does the body manage excess hydrogen ions during high-intensity exercise?

The body uses buffers to bind hydrogen ions or transports them into the blood to be exhaled as carbonic acid.

What is the significance of buffers in muscle performance?

Buffers help neutralize excess hydrogen ions, reducing acidity and improving muscle function during high-intensity activities.

What is the consequence of high levels of hydrogen ions on enzyme activity?

High hydrogen ion levels lower pH, which can impair enzyme function and protein sensitivity.

What is the primary byproduct of glycolysis that contributes to acidity?

Lactate, which is produced along with hydrogen ions.

What happens to muscle performance when hydrogen ion levels are too high?

Muscle performance declines due to mechanical blockage of cross-bridge cycling.

What activities are likely to cause significant lactic acid buildup?

High-intensity interval training, such as sprinting or tire flips.

How does temperature affect lactic acid buildup during exercise?

Higher temperatures can impair breathing efficiency, exacerbating lactic acid accumulation.

What is the role of lactobacillus in muscle acidity?

Lactobacillus contributes to the production of lactic acid, which can increase acidity in muscles.

What is the relationship between metabolic acidosis and diabetes?

Diabetics may experience increased acidity due to their body's difficulty in managing certain compounds.

What is the effect of buffers on lactic acid burn during exercise?

Increased buffers in muscles can reduce the sensation of lactic acid burn, allowing for better performance.

What is the physiological impact of hydrogen as a free radical?

Hydrogen can disrupt cellular processes, including the ability to contract muscles effectively.

What is carbonic acid and how is it formed?

Carbonic acid is formed when carbon dioxide binds with hydrogen, and it can be exhaled to help regulate pH.

What is the significance of maintaining a balanced pH in the body?

Maintaining a balanced pH is crucial for optimal enzyme activity and overall metabolic function.

What is the consequence of not properly managing hydrogen ions during intense exercise?

Failure to manage hydrogen ions can lead to decreased muscle performance and increased fatigue.

What is the primary focus of VO2 max training?

To improve buffering capacity at higher intensities, allowing for stronger and faster workouts.

What type of training is emphasized for improving VO2 max?

High intensity bouts with very short rest periods.

Why do marathon and 10K runners seek high VO2 levels?

To enhance their performance, despite needing shorter intervals for acid buffering capacity.

What are the two main types of buffers in the buffering system?

Intracellular and extracellular buffers.

What role does carnosine play in buffering?

Carnosine holds onto hydrogen ions, preventing disruption during high-intensity exercise.

What is beta-alanine's function in sports supplementation?

It helps increase carnosine levels in the body, enhancing buffering capacity.

What sensation is commonly associated with beta-alanine use?

A skin-crawling sensation known as paresthesia.

What is the recommended method for taking beta-alanine for its benefits?

Taking it in double doses throughout the day rather than a single large dose before a workout.

What are sodium bicarbonate and sodium citrate used for in training?

They are used to enhance buffering capacity, but must be dosed carefully to avoid negative side effects.

What is a potential negative effect of excessive sodium bicarbonate intake?

It can cause vomiting if taken in too large a quantity.

Why is training type two muscle fibers important for VO2 max improvement?

Type two fibers store acid buffers and help manage lactic acid buildup during high-intensity efforts.

What is the Norwegian four by four training method?

It involves four minutes of all-out effort followed by two minutes of rest, repeated four times.

What physiological response occurs when lactic acid is produced?

Ventilation increases to help expel carbon dioxide and manage acidity.

What is the goal of the Norwegian four by four method?

To elevate lactic acid levels while minimizing strain on the body.

What is the Wingate test?

A 30-second all-out cycling test used to measure lactate levels and VO2 max performance.

What lactate level is typically aimed for in a valid VO2 max test?

8 millimoles of lactate.

What was the average lactate level after the first Wingate test mentioned?

About 15 millimoles of lactate.

How does lactic acid affect performance during high-intensity exercise?

Lactic acid buildup can lead to fatigue, necessitating effective buffering to maintain performance.

What is the relationship between type one and type two muscle fibers in endurance athletes?

Even endurance athletes with predominantly type one fibers will utilize type two fibers for high-intensity efforts.