G LOSSARY OF T ERMS

Aerobic dissimilation: Aerobic dissimilation refers to the combustion of organic molecules—most often glucose, a much-used source of energy in organisms. During the aerobic dissimilation of glucose, glucose molecules are completely broken down into carbon dioxide and water molecules.

Aorta: The aorta is the main artery in the body. It starts in the left ventricle of the heart, and runs alongside the spinal cord to the abdomen. In an adult human, the aorta is 2-3 centimeters (0.8-1.2 inches) in diameter. While a person is at rest, around 5 liters (1.3 gallons) of blood flow through it per minute.

Ashram: An ashram is the Indian name for a living community and meeting place for members of a religious group. The word is often used in Hinduism to refer to a place of religious learning, frequently a monastery, or place of other religious significance. Mostly, an ashram will also be the home of a holy man. Ashrams were traditionally located far from areas of human habitation.

ATP: ATP stands for adenosine triphosphate, which plays a key role in the body as a source of chemical energy. The concentration of ATP in a cell ranges from 1 to 10 millimolar. A person weighing 70 kilograms (154 pounds) uses around 65 kilograms (143 pounds) of ATP a day while the quantity of ATP in the body at any given moment—free ATP—is only 50 grams (1.8 ounces). Cells therefore continuously produce ATP.

Autodidact: Someone who has taught him or herself through self-study and without supervision from a teacher or educational institution. The term is primarily used for self-teaching the equivalent of a substantial education, such as at university or a similarly high level.

Autoimmune disease: A disease in which the body attacks itself and is the cause of its own sickness. They occur when the immune system, designed to defend the body against intruders, produces antibodies to attack its own cells and tissues by mistake. We become sick because the body is trying to protect us from ourselves.

Autonomic nervous system: The autonomic nervous system regulates processes in the body such as temperature, heart rate, blood pressure, breathing, the dilation and contraction of the blood vessels, and the workings of the digestive system. The term autonomic suggests that we cannot influence these processes, but Wim Hof has conclusively shown that this is possible. The autonomic nervous system consists of two parts: the sympathetic and the parasympathetic systems.

Blood platelets: Blood platelets (thrombocytes) ensure that the blood coagulates. If a blood vessel is damaged, the platelets bind to the vessel wall and to each other, forming a scab that seals the leak. People with a deficit of blood platelets can suffer severe hemorrhaging.

Brown fat tissue: One of the two types of fat tissue found in mammals. Unlike white fat tissue, which primarily acts as energy storage, the main function of brown fat tissue is to generate body heat by burning fatty acids and glucose. Brown fat owes its name to the large quantity of mitochondria in its cells—many more than in the white fat tissue cells—which give it a brown color. Brown fat tissue only occurs in mammals.

Buteyko, Konstantin: Buteyko (Ukraine, 1923-2003) devised the method that bears his name. He determined that a carbon dioxide deficiency in the alveoli caused cramping of the blood vessels (hypertension) and of the bronchi (asthma). This led to the treatment known as the Buteyko method.

Capillaries: Capillaries are ultra-thin blood vessels.

Chromosomes: A chromosome is a DNA molecule and contains all of an individual’s genetic information. Every cell in the body contains the same chromosomes. The genetic information is stored in the form of DNA strings. The pieces of DNA that contain this information are known as genes. Genes are always found in the same place in a chromosome in individuals of the same species.

Conditioning: Conditioning is a form of teaching, where linking two stimuli causes the response to one of the stimuli to change. It was first described by Russian researcher Ivan Pavlov. While studying the digestive processes of dogs, Pavlov discovered that they started salivating before he gave them food. He investigated this phenomenon further, to see whether he could teach the dogs to salivate unconsciously. He did this by ringing a bell five seconds before he fed the dogs. After doing this a few times, he observed that the dogs associated the bell with being fed. Soon, they started salivating when they heard the bell, without any food present.

Corpuscles, red and white: Red corpuscles (erythrocytes) are the most common form of corpuscles. They transport oxygen through the body with the aid of hemoglobin, a protein that is an excellent carrier of oxygen. Hemoglobin binds with oxygen easily, through iron. A shortage of hemoglobin and iron is known as anemia. The main function of white corpuscles (leukocytes) is to protect the body against everything foreign to it. In the event of a blood transfusion, the white corpuscles produce antibodies to combat the white corpuscles of the donor blood. In the best possible scenario, the patient suffers no ill effects from this process, but the antibodies can often cause a fever or worse side effects. To prevent this, the white corpuscles are filtered out of the donor blood as much as possible. This filtering process, known as leukocyte depletion, is applied during all blood transfusions.

Corticosteroids: These anti-inflammatory drugs are similar to a hormone produced by the body in the adrenal gland cortex. They are prescribed to combat various health problems and joint damage caused by rheumatism. Well-known corticosteroids are prednisone and prednisolone.

Cortisol: Known as the stress hormone, cortisol is released during all forms of stress, both physical and psychological. It is not the only stress hormone. Cortisol ensures that certain proteins in muscles are broken down, releasing amino acids from which glucose (energy) can be generated. This energy can be used to bring the body back into equilibrium. At the moment of stress, adrenaline and noradrenaline are released to make the body more alert and ready for “fight or flight”. Cortisol ensures that this loss of energy can be replenished. Cortisol is produced in the adrenal gland cortex. The quantity produced follows a biological rhythm, meaning that it is not the same at every moment of the day. More is released when the body wakes up, making us feel hungry.

Creatine phosphate: Creatine phosphate (CP) is part of the body’s anaerobic metabolism. It is a high-energy chemical that is stored in the muscle cells. CP is naturally produced in the body and is also found in foods like meat and fish. It ensures that the muscles contract when we start moving. During intense physical activity, CP releases energy quickly through a chemical reaction in which the phosphate is separated. The energy is used to further contract the muscles. Part of the creatine is then released into the blood and expelled from the body in the urine. The rest is absorbed by the muscles, via the liver, to provide more energy at a later stage. It is a self-regenerating system.

Cytokines: Molecules that play a role in the immune system and activate certain receptors. There are various kinds of cytokines which are released by different cells of the body. Some are produced constantly, while others are only released by cells activated during an immune response. The quantity of cytokines also varies, with some working only locally and others throughout the whole body.

Fast-5 diet: This “diet” was (re)discovered by former Air Force doctor Bert Herring. The regimen instructs you to only eat during a five-hour period each day, allowing your digestive system to rest during the remaining hours.

Glucose: Glucose is one of the human body’s main sources of energy. Since it cannot be stored in the body, it is converted into glycogen, a polymer of glucose monomers stored in the muscles and the liver. Around 100 grams are stored in the average human body.

Hemoglobin: Hemoglobin is a protein in the blood of humans and many other animals. It binds with oxygen (oxyhemoglobin) to give blood its red color. Hemoglobin accounts for a third of the content of red corpuscles and is responsible for the transport of oxygen and carbon dioxide via the blood.

Heart rate variability: Heart rate variability refers to the variation in time between two successive heartbeats. Low HRV is a reliable indicator of stress.

Hypothalamus: The hypothalamus is part of the brain’s limbic system. It controls the autonomic nervous system and plays a crucial role in organizing the actions that ensure the survival of the individual and the species, such as eating, fighting, fleeing and mating. It is also important in regulating the body’s temperature.

Immune system: This is a defense mechanism designed to combat intruders and mutated cells in the body. The Latin term “immunis” means “exempt”, and refers to protection from intruders. The body’s immune system is actually an immune response involving multicellular organisms—a large number of cells and molecules work together to attack intruders. Besides protecting us against viruses, bacteria and parasites, the immune system also expels waste chemicals or cancerous and other sick cells from the body.

Lactate: Lactate is produced in muscles, the brain, and other tissues when there is too little oxygen present. Nutrients are absorbed in the body and burned in these organs to supply energy. Oxygen is necessary for good combustion. If sufficient oxygen is available, little or no lactate is produced. But if there is insufficient oxygen, lactate is produced during the combustion process instead of carbon dioxide and water. The lactate is then converted into carbon dioxide and water as soon as sufficient oxygen returns. If that takes too long, however, the lactate accumulates in the blood, disrupting the acid-alkali balance, causing the pH value to drop and leading to acidification.

Melatonin: Melatonin is a hormone produced in the pineal gland from serotonin then released into the blood and cerebrospinal fluid. The quantity released varies depending on the time of day. In many animals, it influences the sleep-wake and reproductive rhythms. In humans, the natural production of melatonin is directly linked to the certain retina receptors’ exposure to light. Exposure to blue light (from sunlight or artificially from a television or a computer monitor) inhibits the production of melatonin. If the exposure to blue light decreases, the natural production of melatonin increases again. This is a signal for the body to reduce activity and prepare for sleep.

Microglia: Microglia are cells found in the macrophages of the central nervous system. They are small cells with a small core. Their cytoplasm contains a large number of lysosomes and other inclusions that are also found in other macrophages. Microglia occur in both the white and the grey matter of the central nervous system.

Mitochondria: Mitochondria are the powerhouses of the cell. As they supply cells with energy, there is a link between a cell’s energy requirement and the number of mitochondria it contains.

Neocortex: The neocortex is the most recently evolved part of the brain. Relatively speaking, humans have a large neocortex compared to other mammals. It is home to our language center, our ability to think rationally, and our analytical capacity.

Oxygen saturation: Oxygen saturation indicates the percentage of hemoglobin bound to oxygen in the blood. This percentage should normally be 95% to 100%. Oxygen saturation refers only to the blood oxygen levels in the arteries. It does not indicate the replenishment of air in the lungs or the expulsion of carbon dioxide.

Parasympathetic system: This part of the nervous system is linked to relaxation, and is referred to as the body’s “brake pedal”. When it is active, the heart rate is low and breathing is calm. The digestive system is active and blood circulation is good.

Pineal gland: The pineal gland, or epiphysis cerebri, produces the hormone melatonin. This hormone influences various bodily functions. For example, we produce melatonin when there is insufficient daylight, which may also relate to our varying states of mind in different seasons. We need sufficient daylight (sunlight) to produce enough melatonin, which is released by the pineal gland if our sleep rhythm is correct.

Pituitary gland: This important organ just underneath the brain is the size of a pea—about 1 cm (0.4 inches) in diameter. It weighs no more than half a gram and is located in a cavity at the base of the skull. In a stressful situation, the pituitary gland releases a hormone called corticotropin which ensures that the adrenal glands produce cortisol. During this stress response, the pituitary gland is activated by the hypothalamus>. This interaction, known as the hypothalamic pituitary adrenal (HPA) axis, is a slow response to stress—it takes about 30 minutes before cortisol can be measured in the blood.

Plasma: Plasma consists of proteins, minerals, fats and hormones dissolved in water. It transports the corpuscles through the body and contains hundreds of different proteins—each with a different function. For example, the protein albumin absorbs water, ensuring that it stays in the blood vessels rather than leaching through to the tissues. Plasma also contains coagulating proteins which, together with blood platelets, play an important role in the coagulation process of blood.

Prednisone: prednisone is an anti-inflammatory drug.

PSA: The prostate-specific antigen is a protein normally present in the blood in small quantities. It is produced in the gland tissue of the prostate. It is not yet clear why PSA values vary, but it probably indicates activity in certain parts of the prostate tissue. We know that PSA values can increase with age without signifying irregularities of the prostate.

Receptors: Specific molecules can bind with these proteins in the cell membrane or the cell core. Receptors can receive signals from inside or outside the cell. When a signal molecule binds with a receptor, the receptor can initiate a cellular response. Both endogenous substances, such as neurotransmitters, hormones and cytokines, and exogenous ones like antigens and pheromones can stimulate such a cellular response.

Respiratory rate: This is the number of times that you breathe in a minute. Each breath begins as you start to breathe in and ends when you stop breathing out.

Sympathetic nervous system: This part of the nervous system is linked to action, and is known as the body’s “accelerator”. If this system is dominant, then we are in “fight-or-flight” mode. We breathe faster, our digestive system stops working momentarily, and our heart rate increases.

Telomeres: A telomere is a piece of DNA at the extreme end of a chromosome. It becomes shorter each time the cell divides. Telomeres protect DNA—after 50 or 60 times, a cell can no longer divide as the telomere is too short.

Transcription factors: A transcription factor is a protein that binds to the promoter of a gene. It controls the rate of transcription.