Sitting for long hours has become a part of daily life for millions of people, whether in front of computer screens at work, while driving, or even when watching television. Although this behavior may seem harmless, research indicates that it is linked to a wide range of health problems that affect muscles, the heart, and the brain, and may even increase the risk of chronic diseases such as diabetes and some types of cancer. According to Healthline, prolonged inactivity not only affects physical health but also impacts mental health.

More than half of people spend more than six hours a day in a seated position, but a wider waistline is not the only consequence of this lifestyle. Prolonged sitting can cause health damage in the short and long term, making this daily habit more dangerous than it appears.

Among the most prominent harms of prolonged sitting:

1. Weak leg and gluteal muscles

The strength of the leg and gluteal muscles depends on constant use. When a person spends their day sitting, the need to activate these muscles decreases, gradually leading to their atrophy and weakness.

As the strength of the lower body muscles declines, maintaining balance and stability becomes more difficult, increasing the risk of injury.

2. Weight gain

Movement helps muscles secrete enzymes and molecules, such as the enzyme lipoprotein lipase, which plays an important role in processing the fats and sugars consumed by humans. However, when spending most of the day sitting, the production of these molecules decreases, which can affect metabolism.

In a scientific review published in 2025, researchers found a link between physical inactivity and higher body mass index, increased waist circumference, and higher body fat percentage.

Research also indicates that increased sitting time is associated with the accumulation of visceral fat, which surrounds internal organs and is more dangerous than subcutaneous fat, as it is linked to an increased risk of diabetes and heart disease.

3. Hip muscle tightness and back pain

Just as leg and gluteal muscles are affected, the hip muscles also suffer from the effects of prolonged sitting, as staying in a seated position shortens and tightens these muscles.

Furthermore, sitting for long periods, especially with poor posture or an uncomfortable chair, increases pressure on the back and spine.

A review published in 2021 linked prolonged sitting to a 42% increased risk of lower back pain in adults. Meanwhile, children who spend a lot of time using smartphones, computers, or video games were 63% more likely to experience such pain.

A slouched sitting posture may also increase pressure on the spinal vertebrae, accelerating their degeneration and raising the likelihood of chronic back pain.

4. Anxiety and depression

The effects of prolonged sitting are not limited to physical health but extend to mental health as well.

A study conducted in 2025 on young people found that those who did not get enough physical activity were 89% more likely to experience symptoms of anxiety and 149% more likely to experience symptoms of depression.

Other studies suggest that regular physical activity can help reduce the risk of anxiety and depression.

5. Increased risk of cancer

Recent studies indicate that prolonged sitting may increase the risk of some types of cancer.

A review published in 2022 concluded that prolonged sitting is associated with a more than 25% increased risk of ovarian, endometrial, and colon cancer, and also observed smaller increases in the risk of breast, prostate, and rectal cancer.

Researchers suggest this may be because inactivity can lead to hormonal imbalances, insulin resistance, and chronic inflammation, factors that may contribute to tumor growth.

6. Heart disease

Prolonged sitting can negatively affect heart and cardiovascular health.

Extended sitting causes blood to pool in the legs, reducing the amount of blood returning to the heart, and consequently decreasing blood flow throughout the body.

Additionally, the reduced metabolic rate, insulin resistance, and inflammation resulting from inactivity may increase the risk of heart disease.

In a study conducted in 2024, researchers linked spending long hours watching television to higher rates of high blood pressure, coronary artery disease, and heart failure. Another study showed that each additional hour a person spends watching television daily increases the risk of cardiovascular disease by 32% and the risk of stroke by 58%.

7. Increased risk of diabetes and its complications

Evidence suggests that prolonged sitting in front of the television may be more harmful than other forms of sitting.

A study published in 2022 found that people who spent a lot of time watching television were 135% more likely to develop type 2 diabetes. In contrast, moderate physical activity was associated with a 69% lower risk of developing the disease.

For those already diagnosed with diabetes, inactivity may increase the risk of complications such as stroke and eye diseases.