What is Creatine Kinase?
Creatine kinase also goes by the names creatine phosphokinase or phosphocreatine kinase. It is an enzyme that contributes to your body’s production and use of energy-providing molecules. It is located mostly in the cells of your heart, brain and skeletal muscles.
Intense exercise involving eccentric muscle contractions, such as weight lifting and incline running, that keeps your heart rate around the 50 – 90 per cent bracket is known to increase your creatine kinase levels.
It is mostly associated with chest pains and difficulty breathing, with a plethora of side effects and diseases – which we will get to shortly – associated with higher levels of creatine kinase.
The level of creatine kinase present in your blood depends on several factors, including your gender, ethnicity and how active you are. Normal levels usually range from 22 to 198 activity units per liter of serum. These levels can drastically rise to 200,000 units per liter with some severe health conditions.
What Does Creatine Kinase Do?
Creatine kinase plays a part in your body’s synthesis of energy. It is therefore important for the functioning of your tissues, muscles and organs. Regarding your muscles, especially during rigorous exercise, creatine kinase facilitates the process of energy transduction in your muscles and other tissues by catalyzing the formation of energy molecules known as adenosine triphosphate, or ATP. The Adenosine triphosphate (ATP) molecule is a nucleotide known in biochemistry as the “molecular currency” of intracellular energy transfer. Essentially, ATP is able to store and transport chemical energy within your body’s cells.
When we previously mentioned the higher concentrations of creatine kinase being in your muscles, heart and brain, this is because of the increased levels of energy utilization in these areas of your body.
When creatine kinase catalyzes the conversion of phosphocreatine, ATP is degraded to ADP, or Adenosine Di Phosphate. This happens when the third phosphate is removed. As a result, the molecule has just two remaining phosphates, and so the molecule has less chemical energy.
The Different Types of Creatine Kinase
Creatine kinase comes in three different forms. The major subtypes include CK-BB, CK-MB and CK-MM.
CK-BB is isolated from your brain and gastrointestinal and urinary tracts.
CK-MB is located in your heart.
CK-MM is found in your skeletal muscle and heart. It is also the main subtype of creatine kinase in your blood. When CK-BB and CK-MB are found in your blood this can signify health conditions.
Benefits of Creatine Kinase
Photocreatine’s aforementioned function as an energy reservoir serves as a rapid ATP regenerator where it is quickly used up for energy in areas including your muscles along with your brain, photoreceptor cells of your retina, inner ear, spermatozoa and hair cells. Creatine kinase is therefore important in those tissues for the intracellular transport of energy.
Side Effects of Creatine Kinase
The side effects and detrimental consequences of high creatine kinase levels are widely known thanks to extensive research. General side effects include:
Chest pain or pressure
Lightheadedness or dizziness
Pain that radiates to the jaw or down the arm
Rapid heart rate (tachycardia)
Dangers of Creatine Kinase
Several traumas and health conditions that can cause damage to your skeletal muscle are also linked to heightened levels of creatine kinase. Elevated levels of creatine kinase in your blood can be a sign of a variety of conditions including from heart disease, muscular dystrophy, nerve damage to thyroid disorders.
Tests for creatine kinase levels are commonly used to detect muscular conditions including inflammation of your muscles, such as polymyositis. Increased levels of creatine kinase can also result in rhabdomyolysis. This is the breakdown of damaged skeletal muscle. Muscle breakdown causes the release of myoglobin into your bloodstream, which is the protein that stores oxygen in your muscles. If you have too much myoglobin in your blood, it can lead to complications of your kidneys. Stroke and other forms of brain damage can also result in an elevated creatine kinase level.
Take Home Message
Creatine kinase is a double edged sword, which on one hand contributes to the synthesis of energy providing molecules as a reservoir for ATP in your muscles, heart and brain when energy is in constant use. The other, darker side to this is that variations in the levels of creatine kinase in your body can lead to health issues from side effects including chest pains and heart conditions to muscular dystrophy and inflammation of your muscles, along with damage to your nerves and kidneys.