These are the most stressful pieces of Ikea furniture to build, according to a study

You probably don't need a study to tell you putting together flat-pack furniture can be frustrating, time-consuming and a test of even the strongest relationships.

But not all flat-packs are as hard to put together as others, which has been confirmed by new research that monitored the heart rates of 100 people as they constructed Ikea's 20 most popular furniture pieces.

The study by hotukdeals came up with a stress score out of 100 for each flat-pack based on factors like heart rate during assembly and the rate of completion.

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It found the most stressful piece of Ikea furniture to put together is the Pax wardrobe, which has a stress score of 85 out of 100 and resulted in heart rates going up by 13 beats per minute (BPM)

Pax wardrobe frames can be customised in a number of ways with different frames, shelves, door and drawer options available.

The second most stressful piece of furniture to construct is the Brimnes storage bed, which has storage drawers underneath the mattress and shelving behind the headboard.

This bed frame had a stress score of 81 with heart rates going up by 12 BPM.

The third most stressful flat-pack from Ikea to construct is the Hemnes day bed, which also has drawers underneath it.

It had a stress score of 79 and heart rates went up 12 BPM.

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On the other end of the scale the Kallax storage system was the least stressful – and quickest – to construct with a stress score of just 9 out of 100, followed by the Billy bookcase, which had a stress score of 23.

Interestingly, the research found the least stressful pieces weren't the ones that left shoppers feeling the most satisfied by the time they were finished building.

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Instead it was the furniture achieving medium stress scores that resulted in the most satisfaction. This suggests having a level of challenged involved in the construction leads to the buyer feeling a sense of accomplishment.

The Ikea pieces that had a medium stress-level (between 65 and 70), but were most satisfying to build are the Nordli bed frame, Nikkeby chest of drawers, Trulstorp coffee table and the Songesand bed frame.