Is it because they use their brain more?

There is some research suggesting that women might need more sleep than men due to various factors, including hormonal cycles and the demands of multitasking.

According to Andrew Huberman, hormonal phases, especially high estrogen phases, are associated with more efficient and dense sleep, even if the total sleep time is less. However, during other phases, women may need more sleep to achieve the same recovery benefits 1.

While there is a prevailing notion that women might use their brains more due to multitasking, this is one of many factors involved. In a WHOOP Podcast, it was noted that women's brains might require slightly more sleep due to multitasking and higher anxiety levels which lead to more REM sleep for emotional stability 2.

Additionally, other experts suggest that hormonal differences necessitate a longer period for recovery, impacting sleep needs 3. Thus, while multitasking could be a factor, it is part of a broader array of physiological and hormonal influences on sleep requirements.