Based on the behaviour of 5,000 participants, the Nielsen study found that the average US smartphone user spent 37 hours and 28 minutes using their apps each month in Q4 2014, up 63% from 23 hours and 2 minutes in Q4 2012.
With the number of apps accessed each month remaining relatively flat at 26.7, the substantial increase in the amount of time spent on them suggests users are engaging with a select number.
"While there appears to be a consumer threshold to the total number of apps people are willing and/or able to actively use during the month, the time they spend engaging on those apps has increased," the report said.
Entertainment, which includes weather reports and e-books, was the most popular category and users spent 13 hours and 20 minutes on these apps per month over the quarter, a significant rise of 26% on Q4 2013.
Gaming had the highest usage of any app in the entertainment category and users spent 10 hours and 2 minutes playing games each month, up 19% from Q4 2013.
The amount of time spent watching video apps also increased a significant 18% to 1 hour and 44 minutes, although music remained the second most popular subcategory with 2 hours and 37 minutes.
Also of note, Nielsen found considerable diversity of app usage among different ethnicities and between men and women.
While men's monthly app usage was slightly higher than women's (27.2 versus 26.3), women spent an average of 38 hours and 2 minutes per month on apps while men spent 36 hours and 51 minutes per month.
African-Americans used the most apps per month (30.3) and also spent nearly 43 hours per month on them. This was almost 8 hours more than white non-Hispanic users (35 hours and 25 minutes) and higher than the time spent by Asian-Americans (37 hours and 14 minutes) and Hispanics (41 hours and 31 minutes).
Data sourced from Nielsen; additional content by Warc staff