Common Exercise and Nutrition Science Terms Explained!

I am a proud fitness and nutrition nerd. I love learning about different training methods and diets and how and why they work. Invariably, this means deep diving into anatomy and physiology and getting elbows-deep in some exercise and nutrition science.

This makes it easier for me to weed out the good training information from the bad and the myths from the truth. After all, if an exercise method doesn’t make scientific sense, e.g., spot-reduction, trying it would be a waste of time.

In addition to enjoying the science of fitness and nutrition, it’s been my job to teach many of these topics to the students who passed through my personal training academy. I’ve discovered that it’s only when you have to explain something to someone else that you really understand it yourself!

Learning just a little anatomy and physiology can help you make better decisions about your own training, enabling you to make more sense of articles and research papers. If nothing else, you’ll be able to avoid nonsensical training, exercises, and diets, as you’ll understand why some things work and others don’t.

With all that in mind, in this article, I’m going to share some of the most common and useful exercise and nutrition science terms with you. I’ve fact-checked each one with my trusty edition of The Principles of Anatomy by G J Tortora and B H Dickinson (1).

Don’t worry – there won’t be a test at the end!

Please note: I’ve tried to keep my explanations clear and straightforward. So, if you are an anatomist or physiologist, please don’t take offense if I’ve omitted some of the finer details! 

1. Anatomical Terms

Anatomy is the scientific study of the structures that make up the human body. This includes muscles, bones, organs, systems (groups of organs), and cells. In the old days, anatomists learned by dissecting bodies and sketching what they saw. Nowadays, anatomists rely more on scans, X-rays, and imaging, although dissection still occurs.

There are numerous anatomical terms, and some of the most common are outlined below.

Anterior – referring to structures on the front of the body. For example, the tibialis anterior is the muscle on the front of your shin bone. Similarly, the serratus anterior is a muscle on the front of your upper rib cage. Why serratus? Because it looks a bit like the edge of a serrated blade.

Posterior – this term means the back or rear of your body. You are probably already familiar with the posterior (or rear) deltoid. There are other muscles with the word posterior in their name, such as posterior tibialis (back of the shin bone).

It’s important to train anterior and posterior muscles relatively equally in exercise. For example, if you do ten sets for your chest, you should also do ten for your back. Anterior/posterior muscle imbalances will affect your aesthetics (appearance), posture, and performance and could even lead to injuries.

Superior – in anatomical terms, superior means uppermost or closest to the head. It differentiates between similar muscles or muscle fibers. For example, the superior trapezius is the scientific name for what most of us call the upper traps.

Inferior – where superior means uppermost, inferior means lowermost. So, what most of us call the lower traps could be referred to as the inferior trapezius fibers.

Superficial – this term means closer to the surface. For example, many of the muscles we aim to develop are superficial and readily seen, such as the biceps and pecs.

Deep – the opposite of superficial and referring to structures that are further away from the surface of the body. For example, the rotator cuff is deep because it lies beneath the deltoids.

Medial – medial means toward the midline of the body or middle in general. For example, the medial deltoid is your middle shoulder muscle, which lies between the anterior and posterior deltoids.

Lateral – this term is the opposite of medial and refers to the outer regions of your body. For example, vastus lateralis is your outermost quadriceps.

Proximal – proximal means a point on a limb or bone near the midline of the body. For example, the proximal end of the femur or thigh bone connects to the pelvis to form the hip.

Distal – the opposite of proximal, this term refers to a point toward the end of a limb or bone. For example, your hands are at the distal end of your forearms.

2. Physiological Terms

Where anatomy is the study of the structures of the body, physiology is the science of how those structures work. Training and nutrition can affect your physiology, so knowing a little about how your body works can be useful.

Metabolism – your metabolism is the sum of the reactions that occur in your body. This includes the breakdown of various substances for energy and the synthesis of molecules for growth and repair. Metabolic rate refers to the quantity and speed of these reactions. Your metabolism also plays a critical role in weight management.

Anabolism – this is the metabolic process of turning simple molecules into more complex structures. For example, building muscle is an anabolic process. Anabolism also refers to energy storage, e.g., increasing body fat.

Catabolism – catabolism is the breakdown of complex structures into simple molecules. For example, eating carbs and turning them into glucose for fuel. Catabolism also occurs during and after intense exercise. It’s one of the triggers for muscle growth.

Related: Anabolism vs. Catabolism

Thermogenesis – the reactions in your body generate heat, and we call that thermogenesis. This is one of the ways we regulate body temperature. Diet and exercise also influence thermogenesis. For example, eating a high-protein meal increases thermogenesis. That’s why protein is a metabolism-boosting food.

Glycogenesis – this is the process where carbohydrates and glucose are converted into glycogen (glucose plus water) for storage in your muscles and liver, ready for later use.

Glycogenolysis – turning glycogen back into glucose is called glycogenolysis, making it the opposite of glycogenesis. Glycogen is the fast-acting fuel we use during high-intensity activities, e.g., sprinting and lifting weights.

Lipolysis – this is the breakdown of stored fats (lipids) into fatty acids and glycerol. We then use these substances for energy. This process speeds up during periods of fasting or prolonged exercise.

Protein synthesis – we call the process of using amino acids to repair and build the structures of the body protein synthesis. This is one of the reasons that bodybuilders need to consume plenty of adequate protein, which is where we get amino acids.

3. Nervous System Terms

The neurological system comprises your brain, spinal cord, and peripheral nerves. It’s how your body receives information from the outside world, processes it, and responds. It’s no exaggeration to say that your nervous system is the big boss of your entire body.

Central nervous system (CNS) – the CNS is your brain and spinal cord. The brain processes inputs and produces outputs, while the spinal cord links the brain to all the branches of the nervous system.

Peripheral nervous system (PNS) – the PNS describes all the branches of nerves running to and from the CNS. Some of these nerves are very short, e.g., from one vertebra to the next. In contrast, others are very long, e.g., the nerve that runs the length of your leg to your big toe.

Sympathetic nervous system – the sympathetic nervous system gets your body ready for “fight or flight” during stressful situations. It’s an autonomic system, meaning we have very little control over it. When triggered, this system raises your heart rate and blood pressure, dilates your pupils, increases muscle tension, and dumps glucose in your blood for instant energy.

Parasympathetic nervous system – after your sympathetic nervous system has done its job, the parasympathetic nervous system steps in. It helps calm you down and returns your body to a more neutral state. This includes lowering your heart and breathing rate and decreasing your blood pressure. This system helps you “rest and digest” after fight or flight.

Motor nerves – these are the nerves that carry messages from your brain to your muscles. They trigger muscle contractions and can be voluntary, e.g., during exercise, or involuntary, e.g., withdrawing your hand quickly from something hot.

Sensory nerves – sensory nerves carry information about your internal and external environment to your brain. This includes pain, temperature, texture, and position. Your brain then analyzes this input and decides how to react, often in milliseconds.

Neurons – these are the basic building blocks of the nervous system and are responsible for transmitting electrical signals throughout the body.

Axons – an axon is a long chain of neurons. They transmit information to and from the CNS. Axons link to organs, muscles, and other neurons, allowing information to pass freely.

Action potentials – an action potential is the electrical signal that travels along the axon of a neuron. Also known as a nerve impulse, both sensory and motor neurons use action potentials to transmit information.

Neurotransmitters – these are chemicals that work with the nervous system. Examples include dopamine, which is a feel-good chemical, and acetylcholine, which plays a critical role in muscle contractions and various brain functions, including memory.

Proprioception – proprioception describes how your body senses where it is in time and space. For example, your body uses proprioception to stabilize your feet and ankles when walking on a rough surface in the dark. It also ensures you adopt the correct posture during exercises like squats and lunges.

Reflexes – a reflex is an automatic response to a stimulus. Reflexes happen without conscious thought because. They’re processed by the spinal cord rather than the brain, bypassing conscious decision-making. Reflexes are almost instant reactions, e.g., jumping out of the way of an oncoming car to avoid an accident.

4. Energy System Terms

Your body is constantly producing and regulating your energy levels. It does this by using three separate but overlapping systems. Different workouts challenge different energy systems, so knowing how each one works is often helpful. That way, you can choose the best one for your fitness goals.

That said, the energy systems are also very complex, and there are entire books about each one. Don’t worry – I plan on keeping this section short and sweet. After all, there is only so much science that we meatheads, sorry – fitness enthusiasts – need to know!

Adenosine triphosphate – known as ATP for short, this high energy yield compound is made from one adenosine and three phosphate molecules. When acted upon, it breaks its bonds and releases a burst of chemical energy. ATP then becomes adenosine diphosphate, or ADP for short. ADP then regenerates back into ATP.

All human energy comes from ATP, although we make it in several ways using one of three different systems.

Mitochondria – these are the parts of our cells that produce ATP. As such, they are often known as “powerhouse cells.” Mitochondria size and density increase with training. That’s one of the reasons that we get fitter and develop better endurance over time.

Aerobic system – unless you are currently exercising very intensely, you are probably producing ATP using the aerobic system. That means with oxygen. The aerobic system breaks down fats and carbohydrates to form ATP. As such, energy is virtually unlimited, as this system can use body fat for fuel.

The aerobic system is most active during low-intensity activities, e.g., steady-state cardio. At very low levels of effort, fat is the primary source of energy. As intensity levels rise, your body uses more carbohydrates and less fat.

Lactate energy system – as activity intensity levels rise, your body is unable to break down fat fast enough to make ATP, so it switches to glucose and glycogen. It does this anaerobically or without oxygen.

This energy comes with a byproduct – lactate – and an accumulation of hydrogen ions, eventually bringing energy production to a halt and forcing you to stop and rest. Unlike the aerobic system, which works as long as fat and oxygen are available, the lactate system can only operate at full capacity for 1-2 minutes.

ATP-CP/Phosphagen system – the ATP/CP system relies on the ATP already in your muscles, which your body regenerates using creatine phosphate. However, both of these substances are very limited. Hence, the ATP/CP system only works for short bursts at high intensity, e.g., 10-second sprints. Like the lactate system, the ATP/CP system is anaerobic, meaning it works without oxygen.

Glycolysis – this is the metabolic pathway that converts glucose into a substance called pyruvate. Glycolysis results in the production of ATP and can occur both anaerobically (without oxygen) and aerobically (with oxygen). In an anaerobic environment, pyruvate converts into lactate. Glycolysis is a critical stage in the function of the aerobic and lactate energy systems.

Lipolysis – this term describes the breakdown of lipids (fats) into fatty acids and glycerol, which can then be used to generate ATP. This occurs in the presence of oxygen, i.e., in the aerobic energy system.

Energy system interplay – while it’s easiest to describe the three energy systems as separate entities, they actually work together. Each one takes on more of the work as circumstances dictate. For example, while the aerobic system is most active during a slow walk, the other two systems are also working, albeit at a low level.

In contrast, as intensity levels rise, the anaerobic systems come to the fore, and the aerobic system takes a back seat. However, it’s still working and ready to take over again when you slow down or stop.

So, the energy systems are best thought of as a sliding, overlapping scale, with all three working simultaneously, albeit contributing varying amounts of ATP depending on activity intensity.

5. Metabolism Terms

If you have been paying attention, you already know that metabolism is the sum of all the reactions within your body. This includes breaking food down, repairing and building muscle, energy storage, and keeping your lungs breathing and heart beating.

However, there are various terms associated with metabolism that exercisers should be aware of. These include:

Basal Metabolic Rate (BMR) – your BMR is the amount of energy your body uses at rest in 24 hours. This includes supporting essential functions, including breathing and temperature regulation. We measure BMR in a fasted state.

Discover your estimated BMR with this calculator.

Resting Metabolic Rate (RMR) – this measure is slightly higher than BMR as it allows for light physical activity and eating. However, given the variability of these additions, RMR is not a very reliable measure of energy expenditure.

Estimate Your RMR here.

Non-Exercise Activity Thermogenesis (NEAT) – NEAT is the energy you use during physical activity that is not formal exercise. Examples of NEAT include walking for transport, chores, and even fidgeting. NEAT is highly variable and can contribute a little or a lot to your daily energy expenditure. It all depends on your lifestyle.

Thermal Effect of Food (TEF) – eating, digesting, utilizing, and storing the nutrients in your food uses energy. This is known as the thermal effect of food or TEF for short. TEF varies from food to food but is generally higher for protein and lower for fats. This explains why high-protein diets are often associated with weight loss.

Exercise Activity Thermogenesis (EAT) – it should be no surprise to learn that EAT is the amount of energy you use during your workouts. However, most people overestimate the energy costs of exercise. While exercise definitely burns calories, it’s not always enough to offset a bad diet or cause weight loss.

Excess Post-Exercise Oxygen Consumption (EPOC) – exercise causes a notable rise in your metabolic rate. This increases your caloric expenditure for several hours after your workout is over. EPOC is also known as the Thermal Effect of Exercise, or TEE. EPOC is highest after high-intensity training, such as HIIT and circuit workouts.

Active Metabolic Rate (AMR) – your AMR is basically the sum of all energy used during planned and unplanned physical activity, including exercise. It’s the total of your RMR, NEAT, and EAT

Total Daily Energy Expenditure (TDEE) – TDEE is the total of all the measures associated with your metabolism. This includes exercise and no-exercise activities and the energy used by eating.

Calculate your TDEE here.

6. Skeletal System Terms

You probably don’t spare much time thinking about your bones. But, without your skeletal system, you’d be nothing but a puddle of soft tissue and liquid!

Your bones give your body shape and structure and provide attachments and levers for your muscles. They’re also a mineral storage site and where we find bone marrow, which produces red and white blood cells.

Here are some of the most common skeletal system terms:

Bone density – the denser your bones, the stronger they’ll be. Weight-bearing exercises like walking, running, and resistance training can increase bone density and strength.

Osteopenia – bone density naturally peaks in early middle age and gradually decreases after that. This is part of the aging process and is known as osteopenia. A possible precursor of osteoporosis, weight-bearing exercises can help improve bone density and reduce osteopenia.

Osteoporosis – leading on from the point above, significant loss of bone density is called osteoporosis. This basically means porous bones. Symptoms of osteoporosis include loss of the bone matrix, decreased height, severe back pain, and increased fracture risk. Resistance training can help prevent and reduce the severity of osteoporosis.

Wolff’s law – bones, like muscles, adapt to the forces placed upon them. Essentially, bones get stronger when you stress them. This adaptability is called Wolff’s law.

Bone remodeling – bone tissue is constantly being broken down and rebuilt. We call this bone remodeling. Ideally, bone building should outpace bone breakdown or happen at the same pace to avoid bone loss. Exercise accelerates this process, making bones stronger over time.

Osteoblasts – these are the cells responsible for forming new bone. Weight-bearing activities and strength training stimulate the osteoblast cells.

Osteoclasts – these cells are responsible for breaking bone down and removing old bone tissue. This is a natural and necessary process. But, it can be problematic if it outpaces the work of osteoblasts.

Periosteum – this is the tissue that covers the outer surface of bones. When muscles pull on the periosteum, it triggers osteoblasts to start laying down new bone tissue. “Peri” means around, and “osteum” refers to the bones. The periosteum also contains nerves and blood vessels.

Ligaments – ligaments are inelastic, avascular fibrous straps and cords that connect bones to bones to form joints. They provide joint stability and prevent unwanted movements. Ligaments get stronger in response to exercise.

Articular cartilage – this is the main type of cartilage found in joints. It covers the surface of the ends of your bones, helping to reduce friction and absorb shock. Cartilage is blue-white in color, indicating a poor blood supply. It’s very tough, but if you injure it, damaged cartilage is slow to heal and may need surgery to repair it.

Synovial fluid – found in the cavities of joints, synovial fluid lubricates and nourishes the articular cartilage. It’s produced on demand, which is why exercise often makes joints feel less stiff and more mobile.

7. Joint Action Terms

A joint occurs whenever two bones meet. Some joints are immovable, such as those in the skull and parts of the pelvis. Others are semi-movable, like those of the spine. Some joints, like the knees, hips, and shoulders, are freely moveable.

All joint movements have anatomical names, which we often use to describe exercises. However, it’s important to note that many exercises feature multiple joint actions. For example, the lat pulldown involves simultaneous elbow flexion, shoulder adduction, and shoulder extension.

Flexion – this is where the angle of a joint decreases, such as bending an elbow or knee. Most flexion exercises are pulling movements, e.g., leg curls and biceps curls. We also class bending forward at the hips or spine as flexion.

Horizontal flexion – horizontal flexion is flexion that occurs in the horizontal plane. It refers specifically to the shoulders. Examples of horizontal flexion include the pec deck, cable crossovers, dumbbell flies, and push-ups.

Extension – this is where the joint angle increases, such as straightening an elbow or knee. Extension exercises are mostly pressing movements, such as leg press, triceps pushdown, and leg extensions. You can also extend your hips and spine.

Horizontal extension – again, referring to the shoulders, horizontal extension is extension in the horizontal plane. Examples of horizontal extension exercises include face pulls and wide-grip rows to your chest.

Hyperextension – hyper means too much or too far. Hyperextension typically means straightening a joint beyond what is safe or healthy. For example, extending your knee past straight or leaning too far backward. In most cases, you should avoid hyperextension, which can cause acute and chronic injuries.

Abduction – abduction is the movement of a limb away from the midline of the body. Examples of this joint action include lateral raises for the medial deltoids and hip abductions for the glutes.

Adduction – adduction means moving a limb into the midline of the body. Examples of this include cable crossovers and hip adductions.

Medial rotation – this is rotation toward the midline of the body, e.g., some rotator cuff exercises.

Lateral rotation – rotation away from the midline of the body, e.g., some rotator cuff exercises.

Protraction – protraction is a specialized movement that only occurs at the shoulder girdle. This is the collective term for the clavicles and scapulae. Simply put, protraction involves pushing the shoulder girdle forward.

Retraction – retraction is the opposite of protraction and involves pulling your shoulder girdle back. This movement is a common exercise cue and helps stabilize your shoulders and upper back.

Elevation – we call lifting your shoulders (or, more correctly, your shoulder girdle) elevation. It’s usual to perform this movement during shrugs, upright rows, and other upper trapezius exercises.

Depression – the action of drawing your shoulders down is depression. You perform this action during pull-ups and pulldowns to protect your shoulder joints and provide your lats with a solid foundation from which to work.

Circumduction – this is a cone-shaped movement that occurs at ball and socket joints, i.e., the hips and shoulders. Imagine making large circles with your arms. That’s circumduction.

Lateral flexion – side-to-side movements of the spine, e.g., during dumbbell side bends.

Pronation – this movement is when you rotate your wrists to turn your palms downward. Pronation is most often used when describing what grip to use. Pronation also refers to the foot and ankle position when discussing gait.

Supination – supination is the opposite of pronation and refers to turning your palm upward. Like pronation, it’s used to prescribe which grip to use and in connection with gait.

Dorsiflexion – ankles don’t flex and extend. Instead, they have unique movement terms. Dorsiflexion is the action of pulling your toes up toward your shins.

Plantarflexion – pointing your ankles, like when you rise onto your tiptoes during calf raises, is called plantarflexion.

Bilateral – movements where both your left and right limbs work together are bilateral. Examples include squats, push-ups, and barbell curls.

Unilateral – unilateral exercises and movements involve or emphasize one limb at a time. Examples include single-leg squats, one-arm push-ups, and running.

Contralateral – contralateral movements involve opposite limbs working together, such as your left arm and right leg. For example, you could do a left-leg-leading lunge and an overhead press with your right arm. Walking and running are contralateral activities.

Ipsilateral – this means the same arm and same leg working together. While you can perform ipsilateral exercises, such movements are rare.

8. Muscular System Terms

I know that many of you will have jumped to this section. After all, muscles are one of the biggest areas of interest for most exercisers. Whether you want to look good, perform well, burn more calories, improve your posture, or just be healthy, muscles matter.

These are some of the most common terms regarding the muscular system:

Muscle fibers, myofibrils, and sarcomere – muscles comprise bundle upon bundle of muscle fibers. Each fiber is made of thread-like structures called myofibrils. The contractile part of a myofibril is called a sarcomere. The sarcomere consists of two proteins – actin and myosin. These components work together to create muscle contractions.

Motor units – a motor unit is a group of muscle fibers and the motor neuron (nerve) that innervates or controls them. The size of a motor unit varies depending on the muscle and its function. Motor units contract with 100% of their strength or not at all. This is called the all-or-nothing law. We recruit more or less motor units to generate varying amounts of force.

Sliding filament theory – this term describes how, when a muscle contracts, the actin and myosin filaments slide over one another to produce movement. So, while a muscle appears to shorten when it contracts, what’s really happening is that its components are moving past one another.

Fascia – the fascia is a layer of thin, tough connective tissue surrounding, separating, and linking all muscles and organs. Regarding the muscular system, it allows smooth movement between adjacent muscles and bones. Fascia is also elastic and stores kinetic energy to aid in movement.

Tendons – tendons attach muscles to bone, transmitting the force generated by the muscles to produce movement. Tendons are tough, inelastic, and avascular. The Achilles tendon is probably the most well-known example and attaches your calf muscle to your heel bone. Tendons get stronger with regular training, albeit at a slower rate than muscles.

Muscle fiber types – anatomists classify muscles by their fiber type. There are three broad groups. These are:

• Type I muscle fibers, also known as slow-twitch fibers, these fibers excel in sustained, low-intensity activities.
• Type IIa fibers, or fast-twitch oxidative fibers, are versatile and capable of both power and endurance. They are active during moderate-intensity work.
• Type IIb fibers, also known as fast-twitch glycolytic fibers, are designed for short bursts of high-intensity activity. This includes sprinting or heavy lifting.

Hypertrophy – this is the scientific term for growth. Organs, including the heart, can enlarge through hypertrophy. However, most exercisers are more interested in muscle hypertrophy. Hypertrophy means over-feeding, which is a clue to one of the things you need to build bigger muscles: extra calories and abundant protein.

Atrophy – if you don’t use your muscles, they’ll become smaller and weaker, which is a process called atrophy. This explains the phrase “use it or lose it” and why you must keep training to maintain your gains.

Sarcopenia – muscle mass naturally peaks when you are in your early 30s. After that, your muscles gradually get smaller and weaker. We call this process sarcopenia. While some age-related muscle loss is unavoidable, lifting weights is the best way to minimize, prevent, or reverse it.

Delayed onset muscle soreness (DOMS) – every exerciser is familiar with DOMS. However, despite its prevalence, science still does not know the exact cause. Theories include microtears in the muscles, inflammation, and the accumulation of lactic acid.

What we do know is that DOMS is not a reliable indicator of a productive workout. As such, there is no need to train for DOMS or worry that your muscles aren’t sore after a workout. DOMS tends to be worse after doing new exercises or training harder than you are used to. Beginners usually experience more severe DOMS than more experienced exercisers.

9. Muscle Actions and Roles

Most exercisers work out with very little thought of what’s going on beneath their skin. This is a mistake. Concentrating on your muscles, known as the mind-muscle connection, can enhance your workouts and aid your performance. The following terms describe the various functions of your muscles during movement and exercise.

Concentric – a concentric contraction occurs when your muscles generate force by shortening. Examples include lifting a barbell off the floor during deadlifts and curling a weight up to your shoulders during biceps curls.

Eccentric – eccentric contractions occur when your muscles lengthen under tension. For example, when lowering down from the top of a pull-up or the bar to your chest in bench presses. You are stronger eccentrically than you are concentrically. As such, you should generally lower your weights more slowly than you lift them. This is especially true for hypertrophy training.

Isotonic – an isotonic contraction pairs a concentric contraction with an eccentric contraction. Most conventional strength training exercises are isotonic.

Isometric – isometric contractions occur when a muscle generates force without changing length. The plank and wall-sit are examples of isometric contractions. Isometric training is another way to build strength and muscle size.

Agonist – the agonist in an exercise is the muscle responsible for doing the majority of the work. Also known as the prime mover, this is usually the muscle you’re targeting with your chosen exercise. For example, the agonist in the bench press is the pectoralis major or chest muscles.

Antagonist – the antagonist is the muscle that opposes the agonist. It must relax to allow the agonist to produce movement. For example, in the leg extension, the hamstrings are antagonists to the quadriceps.

Synergist – synergists are helper muscles. You’ll generally find them at a nearby joint, and they modify the movement you are performing. For example, in lat pulldowns, the latissimus dorsi of the upper back is the agonist. However, the biceps are also working, making them the synergist.

Fixator – fixators are stabilizer muscles that work to prevent unwanted movement. The rotator cuff and core are common fixators, but all muscles can do this job when required.

10. Cardiovascular System Terms

Cardio should be part of everybody’s training routine. It helps with weight management, improves your general health, and could even help you live longer. The fitter you are, the quicker you’ll recover between strength training exercises, too. These are some of the most common cardiovascular system terms.

Cardiovascular – anything pertaining to the heart (cardio), lungs, and circulatory system (vascular). As such, cardio exercises like running and cycling affect the cardiovascular system.

Heart Rate (HR) – the number of times your heart beats per minute. HR can be an indicator of cardio training intensity. HR is typically expressed as beats per minute, or BPM for short.

Resting Heart Rate (RHR) – this is the number of times your heart beats when you are at rest. A low RHR, e.g., below 60 BPM, can indicate a good level of cardiovascular fitness. Your RHR increases when you are tired or unwell. As such, it’s one of the symptoms of overtraining.

Maximum Heart Rate (MHR) – your MHR is the highest heart rate you can achieve during intense exercise. We use the formula 220 minus your age to determine MHR. However, this is not accurate for all.

Heart rate training zones – these are measures associated with cardiovascular exercise intensity. They can be used to prescribe and monitor the difficulty of your cardio workouts. The most common interpretation of rate training zones is:

• Zone 1 (50-60% MHR): This recovery zone is ideal for warming up and cooling down. Exercise here is low intensity and helps improve overall health.
• Zone 2 (60-70% MHR): Known as the aerobic or fat-burning zone, this is where moderate exercise occurs. It’s excellent for building endurance and burning fat.
• Zone 3 (70-80% MHR): This is the aerobic to anaerobic transition zone. Exercise here improves aerobic capacity and is still sustainable but requires more effort.
• Zone 4 (80-90% MHR): This is the anaerobic zone, where high-intensity interval training (HIIT) often occurs. Exercise at this level improves speed and power but is hard to sustain for long periods.
• Zone 5 (90-100% MHR): This is the red-line zone, where you’re working at maximum effort. Training here is extremely intense and can only be maintained briefly.

Understanding these heart rate zones can help you tailor your workouts to meet specific fitness goals, whether it’s improving endurance, burning fat, or increasing speed and power.

Stroke volume – this is the amount of blood the heart ejects per beat. This measure goes up as you exercise. Stroke volume also increases as your heart gets stronger, which is a sign of cardiovascular fitness improvements.

Cardiac output – calculated as heart rate multiplied by stroke volume, this is the total volume of blood pumped by the heart per minute.

Blood Pressure (BP) – blood pressure is the force the blood exerts on the artery walls. There are two BP measures: diastolic, when the heart is relaxing, and systolic, when the heart is beating. Blood pressure increases during exercise but should return to normal shortly afterward. However, chronic high blood pressure is a cause for concern.

VO2 Max – this is the amount of oxygen you can take in, transport, and utilize during exercise. It’s a measurement of aerobic capacity and cardiovascular fitness. VO2 max improves with cardio training.

Estimate your VO2 max here.

Aerobic threshold – at this level of exercise intensity, your body uses a mixture of carbohydrates and fats for fuel, and lactate is efficiently removed. The aerobic threshold is the upper limit for “easy” or “conversational” exercise.

Lactate threshold – this is the exercise intensity at which lactate starts to build up in the blood faster than your body can remove it. While this level of intensity is sustainable, it requires a lot of effort.

Anaerobic threshold – at this level of intensity, your body’s need for oxygen exceeds supply, and you move from aerobic to anaerobic metabolism.

Oxygen debt – more commonly referred to as EPOC or excess post-exercise oxygen consumption. This is the amount of extra oxygen the body needs to recover after exercise.

Rate of Perceived Exertion (RPE) – RPE is a subjective measure of exercise intensity. The original RPE scale, created by Swedish endurance coach Gunnar Borg, went from 6-20. However, the modern 1-10 scale is more popular and easier to use. Exercisers use RPE as an alternative to heart rate training zones. The levels of the 1-10 RPE scale are:

• RPE 1: Resting or very light activity, almost effortless.
• RPE 2-3: Light exercise, you can easily carry on a conversation.
• RPE 4-5: Moderate exercise, conversation is still possible but becoming challenging.
• RPE 6-7: Vigorous exercise, talking is difficult, and you’re breathing heavily.
• RPE 8-9: Very hard training, near maximal effort, talking is almost impossible.
• RPE 10: Maximal exertion, cannot maintain exercise for long, talking is impossible.

11. Endocrine System Terms

Where your nervous system uses electrical impulses called action potentials to transmit information, the endocrine system hormones. Hormones tell your organs and systems how to behave.

Most hormones operate in pairs and work on a negative feedback loop. This means that as levels of one hormone decrease, production of the opposing hormone increases.

Common terms associated with the endocrine system include:

Hormones – hormones are chemical messengers that regulate various physiological processes in the body, including growth, metabolism, appetite, and mood. Most hormones are produced by glands, such as the adrenals and testes, although organs and some tissues make others

Homeostasis – your body uses hormones to create a balanced, stable environment for optimal function and health. This state of balance is called homeostasis.

Testosterone – testosterone is an important hormone for muscle growth and fat burning. We find it predominantly in males but also in females, albeit in smaller amounts. Testosterone is both anabolic and androgenic, meaning it aids in muscle growth and is also responsible for developing secondary male sex characteristics. These include beard growth and a deeper voice.

Estrogen – this is predominantly a female hormone but is also present in smaller amounts in males. It has various functions, including fat storage and regulating menstrual cycles. In men, low testosterone levels are often accompanied by increases in estrogen. Estrogen levels decline with age, leading to the menopause.

Growth hormone – also known as human growth hormone, GH is predominately released during sleep and after intense exercise. It aids cell repair, muscle growth, and fat burning. Growth hormone levels naturally decline with age, and it’s often viewed as the “fountain of youth.” Anti-ageists use GH to make them look and feel younger.

Insulin-Like Growth Factor (IGF-1) – IGF-1 works with growth hormone to promote the growth and repair of muscle cells.

Insulin – produced by the pancreas, insulin ferries glucose from the blood and into the cells, especially the liver and muscles. It’s essential for muscle growth but can lead to fat storage if levels are too high for too long.

Eating carbohydrates triggers the release of insulin. High body fat levels can cause insulin resistance, leading to chronically elevated blood glucose levels.

Glucagon – produced by the pancreas when blood sugar levels are low, glucagon converts stored glycogen back into glucose. It helps to provide energy during prolonged exercise and periods of fasting.

Adrenaline (epinephrine) – made by the adrenal glands, which are on top of your kidneys, this “fight or flight” hormone prepares the body for quick action by increasing your heart rate, redirecting blood to your muscles, and raising blood glucose levels for fast-acting energy.

Cortisol – known as the “stress hormone,” cortisol has a catabolic effect that can break down muscle and inhibit recovery after exercise.

While many people fear cortisol, it’s actually a critical hormone that works in conjunction with adrenaline to balance your nervous system. That said, chronically high cortisol levels can be problematic and are linked to overtraining and chronic stress.

Endorphins – known as “feel-good” hormones, endorphins are natural painkillers and mood elevators, which we release during exercise. They are responsible for the so-called runner’s high, although most forms of exercise produce it, too. Endorphins are what make working out so addictive.

Ghrelin – feeling hungry? Ghrelin could be the reason. This hormone stimulates appetite, and levels of ghrelin increase when you lower your food intake too much too quickly.

Leptin – leptin is produced by your adipose tissue (fat cells). It regulates hunger and satiety by signaling the brain to reduce appetite when you’ve eaten enough. Rapid fat loss causes a rapid reduction in leptin levels, stimulating hunger.

Thyroid Hormones – T3, T4, and, to a lesser extent, calcitonin, are hormones made by the butterfly-shaped thyroid gland, which is located in your throat. They regulate metabolic rate and energy production and affect your ability to lose or gain weight.

Melatonin – levels of melatonin fluctuate throughout the day, usually in time with exposure to sunlight. This is your circadian rhythm, which regulates your sleep-wake cycles. As such, melatonin is crucial for recovery, as many anabolic processes occur during sleep.

12. Nutritional Terms

You are what you eat, or so they say. That’s because everything you eat ultimately becomes part of you or affects your body at a cellular level. Subsequently, your choice of foods and diet can have a significant impact on your training, performance, fitness, and results. Here are the most common nutrition terms you need to know.

Calories – in the context of food, a calorie refers to a kilocalorie, which is a unit of energy. It measures how much energy is in the food we eat. One kilocalorie equals approximately 4.2 kilojoules, the metric unit of energy.

A kilocalorie is the energy it takes to raise the temperature of one kilogram of water by one degree Celsius. Calories are essential for bodily functions like breathing, circulating blood, and regulating body temperature.

Calorie surplus – a calorie surplus is when you consume more than you need for maintenance. This can result in fat gain but is also necessary for those looking to build muscle.

Calorie deficit – a calorie deficit is when you consume fewer calories than your body needs for maintenance. Faced with this energy shortfall, your body will burn fat for fuel to get the energy it needs, usually resulting in weight loss.

Macronutrients – known as the macros for short, these are the main nutrients your body needs for energy and growth. There are three macros: proteins, carbohydrates, fats, and alcohol. While alcohol is not an essential macro, it contains calories, which is why it’s sometimes on our list.

Proteins are essential for the repair and growth of tissues and are a vital component in muscles, skin, and hair. Protein contains four calories per gram, and we get it from meat, fish, eggs, nuts, legumes, and dairy foods.

How much protein do you need? Find out here!

Carbohydrates provide your body with energy. They’re broken down into glucose for immediate use or stored as glycogen for later. Like protein, carbs contain four calories per gram. Example carbohydrate foods include fruit, vegetables, bread, rice, and sugar.

Fats are a concentrated source of energy and contain nine calories per gram. As well as being a fuel source, fats also play a critical role in nutrient absorption and hormone production.

Alcohol is made by fermenting carbohydrates and contains seven calories per gram. Contrary to what many believe, alcohol is not essential and is an anti-nutrient because it contains no vitamins, minerals, or other healthful compounds.

Amino Acids – amino acids are the “protein alphabet.” Your body takes the protein you eat, breaks it down into the constituent amino acids, rearranges them, and then uses the new protein for growth, repair, and other processes.

There are two classifications of amino acids: essential and non-essential. Your body cannot produce the essential amino acids, so they must be present in your diet. In contrast, providing you eat enough essential amino acids, it can synthesize the non-essentials. There are 20 amino acids in total, with 9 being essential and 11 non-essential.

Glycemic Index – known as GI for short, this index ranks carbohydrates according to their

impact on blood sugar levels. Foods with a high GI cause rapid spikes in blood sugar, while those with a low glycemic index result in a slower release of energy.

Initially devised for people with diabetes, exercisers can use the glycemic index to help them decide what carbs to eat and when.

Fiber – also known as roughage or, more correctly, non-starch polysaccharides, fiber is an indigestible plant material. As such, it’s essentially calorie-free and can assist in weight management. Fiber is also very good for digestive health and blood glucose control. Most processed foods are stripped of their fiber, so many people are fiber deficient.

Micronutrients – we only need micronutrients in small amounts, and they don’t contain any calories. Despite this, they’re still vital for various physiological functions. If absent from your diet, ill health is often the result.

There are two main classifications of micronutrients:

Vitamins are organic compounds typically found in plant foods and animals that have eaten plants. Your body can also synthesize some vitamins. Vitamins can be water soluble (B & C) or fat soluble (A, D, E, and K). Your body can store fat-soluble vitamins, but excess water-soluble vitamins are lost through excretion, so we must consume them regularly.

Minerals are inorganic elements such as calcium, iron, and sodium. They are critical for numerous functions, including bone health, muscle and heart contractions, and oxygen transport. Minerals are found in plant foods, and your body stores them, too, e.g., calcium in your bones.

Antioxidants – these are compounds that neutralize free radicals, which are unbalanced molecules. Free radicals damage cells and cause inflammation throughout your body. These unstable molecules are likely responsible for various chronic conditions, including heart disease, cancer, and accelerated aging. Fruits and vegetables are the most readily available sources of antioxidants.

Electrolytes – these are minerals, such as sodium, potassium, and calcium, that regulate fluid balance, muscle contractions, and neural activity. We excrete electrolytes and lose them when we sweat. Most sports drinks contain electrolytes, and eating a diet high in fruits and vegetables will ensure you have a good supply of these essential substances.

Omega-3 and omega-6 fatty acids – known as EFAs, these are special fats that are very good for your health. You cannot make EFAs, so they must be present in your diet.

Broadly speaking, we get omega-3 fatty acids from fish, seeds, and nuts. In contrast, omega-6s come from vegetable and plant oils. However, omega-6s can be pro-inflammatory when consumed in excess. When it comes to omega-3 and omega-6 EFAs, balance is the key.

Probiotics and prebiotics – it’s common to view bacteria as unhealthy, but that’s not always the case. In fact, your digestive system and gut contain more bacteria than your body has cells. These “good” bacteria play a critical role in immunity and digestion.

Probiotics are live bacteria, while prebiotics are substances that promote the growth of beneficial gut bacteria. Sources of probiotics include “live” dairy products, such as kefir and yogurt, as well as fermented foods like kimchi and sauerkraut. You can get prebiotics from garlic, oats, onion, bananas, apples, and barley.

Closing Thoughts

While you don’t need an in-depth knowledge of anatomy and physiology to get fit, lose fat, build muscle, or get strong, it can be helpful. For example, understanding the difference between anabolism and catabolism will help explain why some workouts are better for hypertrophy than others.

In addition, knowing these common exercise and nutrition terms means you’ll be able to decypher almost any training article. Even those on the more technical side. So, why not build your brain as you develop your body? Learn a few of these terms each day, and you’ll soon be fluent!

References:

1. Meskell M. Principles of Anatomy and Physiology. J Anat. 2010 Nov;217(5):631. doi: 10.1111/j.1469-7580.2010.01292.x. PMCID: PMC3035868.

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