Fitness & Exercise Vocabulary in English

Endurance refers specifically to the ability to sustain physical effort over a long period — it is most often used to describe cardiovascular capacity, such as running a marathon or cycling long distances. Stamina is broader and includes both physical and mental staying power: the energy and determination to keep going through a demanding activity. In practice, a marathon runner needs endurance; a footballer who plays hard for ninety minutes needs stamina. The two words overlap considerably and are often used interchangeably in everyday speech, but in sports science contexts, endurance tends to refer more specifically to aerobic capacity.

Aerobic exercise uses oxygen to produce energy and can be sustained for a relatively long time — jogging, swimming, cycling, and dancing are typical examples. Your breathing and heart rate rise but remain at a level you can maintain. Anaerobic exercise is short, intense effort where the body cannot supply enough oxygen fast enough, so it uses a different energy system — sprinting, heavy weight lifting, and interval training are anaerobic. Aerobic exercise mainly improves heart and lung fitness and burns fat; anaerobic exercise builds muscle power and strength. Most gym programmes combine both types for balanced fitness.

In fitness, a repetition (usually shortened to rep) is one complete movement of an exercise. If you lift a weight from your side to shoulder height and back down, that is one repetition. Reps are usually grouped into sets: for example, “three sets of ten reps” means you do the movement ten times, rest, then repeat that twice more. The number of reps and sets you perform, and the weight or resistance used, determines whether you are training for strength, endurance, or muscle size. Understanding the words rep and set is essential for following any gym programme or exercise video in English.

A warm-up prepares your body for the harder exercise that follows. Light activity raises your heart rate, increases blood flow to the muscles, and gradually raises your body temperature — making the muscles more elastic and ready to work. A proper warm-up reduces the risk of injury such as muscle tears and strains, improves your performance in the main session, and mentally prepares you to train. Typical warm-up activities include a brisk walk, light jogging, arm circles, and dynamic stretches. Most fitness professionals recommend at least five to ten minutes of warm-up before any moderate or intense workout.

To hydrate means to take in enough water or fluids to keep the body properly supplied. During exercise, you lose water through sweat and breathing, and if you do not replace it, performance drops quickly. Even mild dehydration — losing as little as 2% of body weight in water — can cause fatigue, reduced concentration, muscle cramps, and a higher risk of injury. Sports professionals recommend drinking water before, during, and after exercise. In English you will often see the noun forms too: hydration (the state of being hydrated) and dehydration (the dangerous state of having too little water in the body).

Both are lower-body exercises but they work in different ways. A squat is performed with feet shoulder-width apart: you bend both knees simultaneously and lower your hips as if sitting onto a chair, then stand back up. This works both legs equally at the same time. A lunge involves stepping forward with one foot, then lowering the opposite knee toward the ground — so you are working one leg at a time. Lunges challenge your balance more than squats and are especially effective for the thighs, hips, and glutes. Both exercises appear in gym programmes, fitness classes, and sports training at all levels.

A rest day is a day when you avoid intense training to allow your body to recover. During hard exercise, muscles develop tiny micro-tears; the body repairs these during rest, and it is this repair process that makes muscles stronger and larger. Without enough rest, you accumulate fatigue, performance drops, and the risk of overuse injuries rises significantly. Most fitness experts recommend at least one or two rest days per week. A rest day does not have to mean total inactivity — a gentle walk, light stretching, or yoga counts as active recovery and can actually speed up the process.

Jogging means running at a slow, comfortable pace that you can maintain for a long time without stopping. It is a popular form of aerobic exercise and is gentle enough for beginners. Sprinting means running as fast as possible, usually over a short distance — 100 metres is a classic sprint distance, but sprint intervals in training can be anywhere from 20 to 400 metres. Sprinting is anaerobic: it demands maximum effort and can only be sustained for a few seconds to a minute. Many training plans combine both: long jogging sessions build base fitness, while sprint intervals develop speed and power.

A personal trainer (often shortened to PT) is a qualified fitness professional who works one-to-one with a client to help them reach their exercise goals. A PT assesses your current fitness level, sets realistic goals, creates a personalised programme, demonstrates exercises correctly, and monitors your progress over time. They also provide motivation and accountability — which many people find just as valuable as the technical knowledge. Personal trainers typically work in gyms, sports centres, or online. In English you might also hear the term fitness coach, which carries a similar meaning but sometimes implies a broader lifestyle or nutrition focus as well.

At A2 level, start with the words you will hear most often in a gym or fitness class: warm-up, cool-down, workout, set, muscle, cardio, jog, sprint, push-up, squat, plank, and rest day. These appear constantly in exercise videos, gym instructions, and fitness apps. Once you are comfortable with these, move on to the B1 words: repetition, endurance, stamina, flexibility, resistance, aerobic, anaerobic, lunge, and hydrate. Following English-language fitness channels on YouTube or reading fitness articles online is one of the fastest and most enjoyable ways to reinforce all of these words in context.