The workout CrossFit®, known for its intensity and variability, It represents an excellent example of how the human body adapts quickly and effectively to extreme physical exertion, both at respiratory and cardiovascular level.
This type of high-intensity functional exercise stimulates the improvement of aerobic and anaerobic capacities, allowing to optimize oxygen consumption and energy management.
Index
What is cardiac and pulmonary adaptation?
Pulmonary Adaptation
A rest, oxygen consumption in an adult is approximately 250 ml/min.
However, during high intensity exercises, such as those typical of a WOD in CrossFit®, pulmonary ventilation can increase up to 20-fold, reaching values of 100-110 litres/minute.
This is about the 50% less than maximal respiratory capacity (150-170 litres/min), which demonstrates that the respiratory system has a significant functional reserve to deal with difficult situations, such as high altitudes or extreme climates.
Maximum oxygen uptake (VO2Max), a crucial parameter in CrossFit®, improves with training.
in this beginners, the increase can reach 10%, while in athletes advanced can exceed 45% normal values, as happens in marathon runners.
Furthermore, the diffusion of oxygen from the alveoli to the capillary blood is optimized, going from 23 ml/min in a sedentary person at rest to the 80 ml/min observed in elite athletes during maximal exercise.
In CrossFit®, benchmark wods as the "Fran"Or the"Murph” challenge the respiratory system, which must maintain stable levels of oxygen and carbon dioxide in the blood, despite high metabolic demand.
This is made possible not so much by variations in gas pressure, but by neurogenic mechanisms that regulate breathing, increasing ventilation in proportion to effort.
Cardiac Adaptation
During a high intensity WOD, blood flow to working muscles increases dramatically to meet the increased demand for oxygen and nutrient supply.
Normally, the flow is about 3,6 ml per 100 grams of muscle at rest, but it can grow by 25 times during intense exercise.
This change is made possible by a combination of factors, including the increase in blood pressure (about 30%) and dilation of blood vessels.
In CrossFit®, consistent training leads to cardiac hypertrophy, especially in more advanced practitioners.
A larger, stronger heart provides a greater cardiac output, which is needed to carry more oxygen and nutrients to the muscles.
This explains why CrossFit® athletes, similar to distance runners, have a significantly lower resting heart rate than sedentary people.
Physiological limits and potential
Performance in CrossFit®, as in other sports, is limited by several physiological factors:
- Pulmonary: alveolar ventilation and gas diffusion capacity improve with training. However, in environments such as high altitude, reduced ppartial pressure of oxygen (PpO2) may negatively affect performance.
- Bloody: oxygen-carrying capacity, influenced by hemoglobin, can be compromised by conditions such as athlete's anemia, often caused by repetitive microtrauma (e.g., during plyometric exercises).
- Cardiocirculatory: cardiac output and capillarization are essential for the transport and use of oxygen. These factors are largely trainable through high intensity exercises, typical of CrossFit®.
- Tissue: The ability of muscle cells to utilize oxygen depends on capillary density and the presence of oxidative enzymes, which increase with training. This process is crucial for improving metabolic resistance during WODs.
CrossFit® and specific adaptations
A unique aspect of CrossFit® is the integration of exercises that combine aerobic and anaerobic capacity.
For example, a workout with burpees, box jumps and thrusters simultaneously stimulates oxygen-carrying capacity, muscle strength and lactic endurance.
This multifunctional approach accelerates cardiac and pulmonary adaptation, improving the athlete's overall resilience.
In conclusion, CrossFit® represents one of the most complete forms of training to promote physiological adaptations.
By simultaneously training respiratory, cardiovascular and muscular capacity, athletes develop a physical condition that makes them ready to respond to any physical challenge, both in and out of the gym.