The most comfortable sofa might actually do you the worst harm.

There are many types of sofas, each with its own advantages and disadvantages. How do you choose? Don't worry, let's compare them one by one.

Leather sofas are high-end and stylish, but they're not very breathable. You might have experienced this: in the summer, you sit on a sweaty sofa, and when you stand up, your skin is still sticky, leaving a red mark.

Wooden sofas are elegant and simple, perfect for a "fresh and clean" style of decoration. However, they are usually quite hard, requiring you to sit upright, which can easily lead to fatigue over time.

Fabric sofas have an elegant style and offer a variety of patterns. However, cleaning them is a headache, as they easily trap dirt and grime, requiring the entire fabric to be removed for thorough cleaning.

Next up is the "beanbag chair," very popular among young people. It's comfortable to lie on or sit on, and once you're in, you don't want to get up. Many people have one at home, relaxing on it after get off work while using their phones – very pleasant. However, be aware that it can also be a "killer" of your spine. To be precise, not only "beanbag chairs," but any unsuitable sofa can harm spinal health.

This isn't just hearsay; many people have experienced problems from sitting on unsuitable sofas for extended periods.

According to a 2015 report in the British Daily Mail, research found that softer sofas can increase lower back pain.

While soft sofas can be comfortable, physical therapist Richard Evans warns that sitting on a soft sofa can lead to poor posture, causing lower back pain; prolonged sitting can also cause postural deformities, putting more pressure on the spine.

So the question arises: given how long modern people sit (an average of over 8 hours),

which sofas are better for the spine?

How should we choose a good sofa?

What posture is best on a sofa?

To answer these questions, first, it's important to understand the structure of a sofa and pay attention to the following three points when choosing one:

Angle

The angle here refers to the backrest angle, which is the angle at which the sofa backrest tilts backward. The angle varies.

Studies have found that different backrest angles offer varying levels of comfort when sitting. Around 110 degrees provides the best comfort, followed by 120 degrees, while approximately 100 degrees offers the worst comfort. In other words, a completely vertical backrest is the most uncomfortable, while a slight tilt is the most comfortable.

Besides comfort, the backrest angle is also important for spinal health. Researchers in Sweden and Japan, through intervertebral disc pressure tests, found that a backrest angle of 120 degrees provides the most favorable conditions for intervertebral disc pressure and muscle activity.

In other words, a backrest angle between 110 and 120 degrees is optimal for both comfort and health; angles that are too large or too small are not ideal.