Physical activity

In research, physical activity is defined as any movement produced by skeletal muscles that uses more energy than resting. Walking, climbing stairs, commuting, cleaning, and physical tasks at work all count.

Exercise is a subset of physical activity. It refers to planned, repeated activity intended to improve or maintain fitness. All exercise is physical activity, but not all physical activity is exercise. Walking to the shops or spending time playing with a child also adds to your total physical activity for the day.

So asking yourself “How much did I move today?” rather than “Did I exercise today?” can give you a more accurate picture of your day.

When looking at physical activity, it helps to distinguish three dimensions.

• Activity volume — The total amount you move over a given period. It is estimated through duration and frequency.
• Intensity — How demanding the movement is. Even a 30-minute walk can vary in intensity depending on speed, slope, the load you carry, and your fitness. The Metabolic equivalent of task (MET), a tool for classifying activities by their energy cost, is a representative value based on an average adult, so it may differ from how demanding an activity actually feels to an individual. You can find more detail on intensity categories in the Physical activity guidelines.
• Sedentary behavior — Time spent sitting or lying down while awake and using very little energy. This is covered separately in Sedentary behavior.

These three dimensions vary independently. Someone who meets the recommended amount of exercise may still spend much of the rest of the day sitting, while someone who does almost no exercise may work on their feet all day. When reflecting on your day, considering “How much did I move, how demanding was it, and how much time did I spend sitting?” separately can help you understand your body's condition.

Physical activity can be grouped according to where it takes place.

• Leisure-time activity — Activities you set aside time for, such as exercise, walks, hiking, dancing, and ball sports.
• Transport activity — Walking or cycling to and from work or school.
• Work and household tasks — Physical movements at work and activities such as cleaning, cooking, gardening, and childcare.

On days when it is difficult to set aside time for exercise, moving your body while traveling or doing household tasks can contribute to your daily activity volume.

This means walking or cycling to and from work. Several large observational studies have reported that people who commute actively tend to have more favorable cardiovascular and metabolic indicators. Even using public transport instead of a car tends to be associated with higher overall activity because it adds time spent walking to stops.

One of the advantages attributed to commuting is that it is repeated almost every day, even if only for a short time. Unlike exercise concentrated into a single session, it fits into everyday routes without requiring extra time, making it easier to sustain. Most of these studies are observational, so it is also important to consider the possibility that people who commute actively have other healthy lifestyle habits as well.

Try these ideas.

• Get off one or two stops early and walk.
• Choose Stair ascent and descent instead of the elevator.
• Walk or cycle for short trips.

This is a metaphor biomechanist Katy Bowman uses to explain Natural movement. The idea is that, just as consuming only one nutrient upsets the body's balance, sitting all day and then doing a large amount of just one exercise at the gym is a kind of “unbalanced movement diet.” The focus is on the variety of movement and its distribution throughout the day, rather than the total amount of exercise.

This metaphor connects with two observations. One is that longer sitting time tends to be associated with worse health indicators, and regular exercise alone only partly reduces that effect. The other is the motor-learning perspective that using the body under varied conditions helps the nervous system and tissues cope with a broad range of situations (Movement variability). It does not mean movement is absorbed into the body like nutrients; it is a way to help explain the idea of getting a balanced variety of movement.

Putting it into practice is not difficult. Try getting up once an hour to loosen up, occasionally varying the slopes and surfaces you walk on, and incorporating movements such as squatting or getting up from the floor into daily life. You can find ways to interrupt sitting in Active breaks from sitting.

Physical inactivity means that your total daily physical activity, including walking, stairs, household tasks, and exercise, does not reach recommended levels. It is a very common lifestyle factor worldwide. Research linking it with declines in strength and cardiorespiratory fitness and worsening of various health indicators has accumulated. Sarcopenia, the loss of muscle mass and strength with age, is also discussed in relation to physical inactivity.

Although physical inactivity overlaps with prolonged sitting, they are not the same thing. Some people get enough activity but spend the rest of their time sitting, while others have low activity levels without sitting for long periods.

Many people worry that movement will wear out their joints. In a large meta-analysis comparing rates of knee and hip arthritis, recreational runners actually had lower rates than people who were largely inactive. The rates reportedly rose again among people training at very high volumes at an elite level. The takeaway can be framed as gradually increasing activity being more comfortable for the body than suddenly increasing it substantially.

The World Health Organization's 2020 guidelines recommend 150–300 minutes of moderate-intensity aerobic activity or 75–150 minutes of vigorous-intensity activity per week for adults, along with muscle-strengthening activity at least twice a week. Movement accumulated in short bouts also counts toward the total, and the previous requirement for bouts of “at least 10 minutes at a time” has been removed. A central message of the guidelines is that doing even a little is better than doing nothing. You can find details in the Physical activity guidelines.