What is exercise, really? Here’s what counts, according to an exercise physiologist

What is exercise: Image shows active senior couple jogging along beach
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We know it’s beneficial for our health and most of us do it regularly but what is exercise? To answer this, it’s important to know the difference between exercise and physical activity. 

Physical activity refers to anything which causes the muscles to move the body. Exercise is a subcategory of physical activity — it’s a structured plan to regularly repeat physical activity.

Exercise is then split into different types: aerobic and anaerobic, with different activities such as walking or swimming falling under these categories. 

So, whether you’re increasing your aerobic fitness by running on the best treadmill (opens in new tab) or doing an anaerobic activity such as Pilates, let’s take a look at what is and what counts as exercise, the different types, why it’s important and how often you should do it.

What is exercise? Exercise vs physical activity

Physical activity is any movement produced by skeletal muscles that requires your body to burn calories, according to the World Health Organization (opens in new tab), while exercise is planned, structured, repetitive, and intentional physical activity, carried out to maintain or improve physical fitness.

“As we exercise, our heart and breathing rate increases which increases blood flow as the body requires more oxygen and fuel to the working muscles,” says exercise physiologist and scientist Richard Avery. 

“The percentage of blood flow distributed to the working muscles is around 20% at rest; this can increase to over 80% during maximal exercise involving large muscle groups, such as running or cycling. If the intensity of exercise is low to moderate these increases will be much lower, and after a few minutes at the same intensity, heart and breathing rate tend to stabilize.”

Aerobic and anaerobic are both types of exercise that differ based on the intensity, interval, and types of muscle fibers incorporated, as stated by the World Journal of Cardiology (opens in new tab).

Richard Avery
Richard Avery

Avery is an exercise physiologist and an applied sport and exercise scientist at the University of East London. He holds an MSc in exercise physiology and currently splits his time across teaching, consultancy work and research.

Aerobic exercise

Aerobic exercise (opens in new tab) is a type of cardiovascular conditioning and is defined by the American College of Sports Medicine (ACSM) as any activity that uses large muscle groups, can be maintained continuously, and is rhythmic, according to the World Journal of Cardiology (opens in new tab).

Avery explains that aerobic exercise uses oxygen as the main fuel and usually refers to activities lasting longer than 3 minutes. Playing a sport regularly, or cycling to work every week are examples of aerobic exercise, he adds.

Man riding a bike through a forest

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Anaerobic exercise

The World Journal of Cardiology (opens in new tab) states the ACSM defines anaerobic exercise as intense physical activity of very short duration.

Anaerobic exercise (opens in new tab) uses energy systems that don’t rely on oxygen, but cannot be sustained for long periods and typically lasts between 10 seconds and 2 to 3 minutes,” adds Avery. 

“Examples of anaerobic exercise include repeated weightlifting or sprinting activities.”

woman working out in gym lifting weights

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What counts as exercise?

Exercise is a habit of being physically active and Avery says it includes any regular physical activities, such as walking, cycling, gardening, skipping, dancing, playing sports, or lifting weights in the gym. 

“Most people can safely and easily build [walking] into their daily or weekly routine, whether it’s a walk to the bus or train as part of your commute, or a walk to catch the sunrise or sunset each day.

“It’s low impact, keeps the body moving, and enables you to select and vary your pace based on your fitness level,” he claims. 

But what counts as exercise for one person might differ for another. For instance, it will take more effort to maintain health and fitness levels for people with high levels of fitness, explains Avery.

If you want to make sure you're getting enough movement into your day, it's a good idea to invest in one of the best budget fitness trackers (opens in new tab). These devices can help you monitor your steps and estimate your daily energy expenditure. 

Why is exercise important?

“Exercise is heavily associated with maintaining and improving fitness,” says Avery, “but it is also very important for maintaining and improving health. Regular physical activity can improve cognitive function, wellbeing, and sleep, by reducing stress and anxiety.”

With regular exercise, he says the risk of certain conditions is reduced, such as:

  • cardiovascular disease
  • coronary heart disease
  • type-2 diabetes
  • hypertension
  • colon cancer
  • osteoporosis

A woman sleeps peacefully on her bed

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How often should you exercise?

According to the Physical Activity Guidelines for Americans (opens in new tab), adults should carry out at least 150 minutes (2 hours and 30 minutes) to 300 minutes (5 hours) of moderate-intensity, or 75 minutes (1 hour and 15 minutes) to 150 minutes (2 hours and 30 minutes) of vigorous-intensity aerobic physical activity spread throughout each week. 

It’s also recommended that adults do muscle-strengthening activities, that involve all major muscle groups, of moderate or greater intensity on two or more days a week.

“Stretching is very useful to enable muscles to work in a full range of motion, particularly before and after moderate to high-intensity exercise,” adds Avery. “Dynamic stretching is recommended before exercise to move the muscles through the range of movement they will go through during the exercise session. Meanwhile, static stretching (holding the muscles in a fixed stretched position for 20 to 30 seconds) is beneficial after exercise to reduce any muscle tightness and improve the range of movement for subsequent activities.”

“When regularly active and consistently performing the same activity, your body will start to adapt over time, to be able to better cope with the demands being placed on it,” Avery explains. “This could result in your heart rate being lower during the same intensity of exercise, compared to a session a month or [few] weeks previously, or it could result in your breathing rate reducing towards resting levels more quickly than before. If you can consistently keep to a new exercise plan, you may start to notice a difference in your fitness within a few weeks, even if it’s as simple as not getting out of breath going up the stairs.”

But how regularly you exercise can differ for each individual and depends on your previous experience, injuries, and the intensity and duration of your sessions, he says. Avery warns: “If you perform lots of high-intensity activities close together and don’t allow enough time for your body to recover and adapt, you may end up overtraining.

“When starting a new exercise plan, or trying to increase your activity levels, make sure you increase the load and intensity gradually, and factor in additional recovery following periods of harder training to avoid burnout.”

Gemma Harris is a UK-based freelance journalist and health writer who blogs at thegutchoice.com. She produces content for multimedia health and lifestyle platforms, including calmmoment.com, StomaTips, Planet Mindful and metro.co.uk because she has a passion for health and wellness. When not writing, she can be found walking or running in nature, at a yoga or spin class, swimming or having cocktails with friends.