Sitting down all day with no physical activity can increase a person’s risk of developing health conditions, such as heart disease, type 2 diabetes, and some types of cancer. Staying physically active can help to reduce this risk.

Physical activity is a crucial part of keeping the body healthy. However, the Centers for Disease Control and Prevention (CDC) estimates that Americans spend between 6.5 and 8 hours per day sitting down, on average.

Office workers, for example, may sit at a desk for hours at a time. Common pastimes, such as reading, watching television, or playing computer games, can also involve sitting down for long periods.

This article will explain what happens to the body when someone sits down for too long, how long is too long to sit down, and how to avoid and prevent the consequences of a sedentary lifestyle.

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Sitting down for long periods, with little physical activity, is part of what doctors call a sedentary lifestyle. The CDC suggests that sedentary lifestyles with no physical activity increase a person’s risk of developing health conditions such as:

Sitting all day without adequate physical activity can also impact a person’s sleep quality, mental health, physical and cognitive abilities, and bone health.

There is no hard and fast answer to the question of how many hours of sitting is unhealthy. It is different for everyone and can depend on factors such as how much exercise a person does each day.

According to the charity Just Stand, the following thresholds determine a person’s risk of developing health problems due to sitting:

  • Low risk: Sitting for less than 4 hours per day.
  • Medium risk: Sitting for 4–8 hours per day.
  • High risk: Sitting for 8–11 hours per day.
  • Very high risk: Sitting for more than 11 hours per day.

The CDC considers 150 minutes of moderate activity per week adequate to lower the risk of some health conditions associated with a sedentary lifestyle.

Prolonged sitting can impact the body in various ways. This can include:

Discomfort

A 2018 study suggests an association between prolonged sitting and musculoskeletal discomfort. Areas that people may experience discomfort in include:

  • neck
  • shoulders
  • lower limbs
  • lower back
  • buttocks
  • thighs
  • wrist and hand

This study examined the effects of sitting for 2 hours. It found that discomfort levels in all body areas rose as time increased.

Slower metabolism

Metabolism is the process by which the body breaks down and uses energy. A 2021 research article suggests that prolonged sitting can affect metabolism after eating.

Researchers in this article recommend regular activity breaks to improve metabolism when sitting for long periods.

Changes to blood flow

According to the same 2021 research article, prolonged sitting can reduce blood flow, particularly to the legs.

This can lead to consequences such as leg swelling.

Hypertension

A 2017 cross-sectional study associates prolonged sitting with hypertension, which is high blood pressure.

6.3% of office workers in the study experienced blood pressure above 140/90 mmHg. The American Heart Association lists this as stage 2 hypertension.

Musculoskeletal disorders

A 2018 article highlights associations between prolonged sitting and certain musculoskeletal disorders of the lower limbs.

Similarly, a 2017 article suggests an association between sitting for long periods and musculoskeletal disorders of the:

  • neck
  • knees
  • thighs
  • lower back

Mental impact

The same 2018 study that monitored people sitting for 2 hours suggests that prolonged sitting has a negative impact on perceived mental state and creative problem-solving abilities.

The 2017 article mentioned above also suggests that sitting for long periods can lead to feelings of exhaustion.

Getting active is the best way to treat the effects or prevent the consequences of sitting all day.

The CDC recommends people get at least 150 minutes of moderate-intensity activity a week. This could be five 30-minute sessions across 1 week.

Moderate-intensity activity might include:

  • brisk walking
  • water aerobics
  • riding a bike on level ground

People can start with less vigorous exercises and build their stamina over time.

A 2021 research article suggests that regular activity offers better benefits than replacing prolonged sitting with prolonged standing.

Anyone who experiences the symptoms of a health condition related to sitting down for long periods should speak with a doctor.

Anyone who already has a health condition, such as type 2 diabetes, heart disease, or osteoporosis, may wish to speak with their doctor before starting a new exercise regime.

Healthcare professionals will usually be able to offer personalized advice on the best way to approach getting active or increasing activity levels.

Staying active is the best way to avoid the consequences of sitting down all day. This can involve getting at least 150 minutes of physical activity each week or introducing regular activity breaks.

For example, a 2022 systematic review suggests the benefits of breaking up prolonged periods of sitting by regularly walking around.

People who work in offices can try to avoid sitting down all day by:

  • asking for sit-and-stand desks or workstations
  • alternating between standing and sitting every 30 minutes
  • having walking meetings
  • regularly stretching while sitting or standing
  • walking to speak with a colleague instead of sending an email

Some frequently asked questions about the health impact of sitting down for too long include:

Is sitting for 8 hours bad for you?

The charity Just Stand classes sitting for between 4 and 8 hours a day as a medium risk of associated health complications. It considers sitting between 8 and 11 hours a day to be high risk.

Can you die from sitting for too long?

Sitting down all day is part of what doctors call a sedentary lifestyle. According to the World Health Organization (WHO), insufficient physical activity is the 4th leading risk factor for death and is responsible for 3.2 million deaths per year worldwide.

A 2017 article suggests people who spend long periods sitting down for work have an almost 1.4 times greater chance of dying prematurely after 12 years than those who do not.

Sitting all day and not getting any physical activity may increase a person’s risk of developing a range of health conditions, including heart conditions, type 2 diabetes, and some types of cancer. It can also impact sleep patterns and mental health.

However, there are things people can do to lower the risks to their health. These include being more physically active overall and breaking up long periods of sitting down by moving around.