Waiting for the post-Christmas sales frenzy to die down so you can enjoy a less stressful shopping experience? Then you might want to make your purchases online instead as experts warn that carrying shopping bags can put a strain on your stress levels as well your back.

A study at the Chinese University of Hong Kong and National University of Singapore found that lifting heavy objects can cause people to subconsciously dwell on serious or depressing matters.

Researchers looked at the impact of physical weight on mental health by questioning consumers.

Participants were divided into two groups. The first group was told to hold shopping bags full of goods before being grilled on an unrelated topic. The second group was questioned on the same topic but was not given any bags to carry beforehand.

It was found that those who were carrying the bags felt the issue was more important than those who were empty handed.

Interestingly, the result was negated in the group that were carrying the bags when they were told to think about light objects such as feathers and balloons.

Lead researchers Meng Zhang and Xiuping Li said their findings suggest physical weight influences a person’s "psychological weight".

They added: "Prior research has shown that the physical experience of carrying weight can influence people’s judgment in unrelated domains such as the importance of an event."

The study will be featured in the forthcoming edition of the Journal of Consumer Research.