The NHANES National Youth Fitness Survey

The NHANES National Youth Fitness Survey (NNYFS) was conducted in 2012 to collect data on physical activity and fitness levels in order to provide an evaluation of the health and fitness of children in the U.S. ages 3 to 15. The NNYFS collected data on physical activity and fitness levels of our youth through interviews and fitness tests.

In October 2008, the federal government issued its first-ever Physical Activity Guidelines for Americans to provide science-based guidance on the types and amounts of physical activity that provide substantial health benefits for Americans. Guidelines for children and teens ask for 60 minutes or more of aerobic, muscle-strengthening, or physical activity daily.

While the number of children in the U.S. who meet the Physical Activity Guidelines is unknown, the percentage of children who are physically active in the U.S. is declining. The inclusion of fitness tests, in the NNYFS for ages 3–15, provides additional information with which to evaluate the health of this age group.

The survey was conducted in 2012 by the Division of Health and Nutrition Examination Surveys, National Center for Health Statistics, part of the Centers for Disease Control and Prevention.

For more information on the NNYFS survey design, implementation, and data analysis, see the National Health and Nutrition Examination Survey: National Youth Fitness Survey Plan, Operations, and Analysis, 2012 [PDF – 1M].

What's New

Data Release

Physical Activity Monitor – Ambient Light Raw Data (Y_PAXLUX 2012)

Data Release – Limited Access Data

NHANES/NNYFS Combined Sample 2012 – Physical Activity Monitor – Ambient Light Raw Data (C_PAXLUX 2012)

Updated Data

The summary ambient light (lux) measures (i.e., PAXLXSH) previously included in the following Physical Activity Monitor (PAM) Minute Summary Files were erroneously described as the ‘sum’ of lux measures at the minute level whereas the values reported are the ‘mean’ lux measures for the minute. The files were updated with the variable PAXLXSH renamed as PAXLXMM and description corrected. No change was made to the data points reported. In addition, the descriptions for the codes associated with the quality check flags were also updated to clarify the data issues denoted by these flags.

Physical Activity Monitor – Minute (Y_PAXLUX 2012)
NHANES/NNYFS Combined Sample 2012 – Physical Activity Monitor – Minute (C_PAXMIN 2012)

The documentations for the following Physical Activity Monitor – Raw Data 80hz Files were updated to clarify the data issues described in the codes associated with the quality check flags. No change was made to the data points reported.

Physical Activity Monitor – Raw data 80hz (Y_PAXLUX 2012)
NHANES/NNYFS Combined Sample 2012 – Physical Activity Monitor – Raw 80 Hz Data (C_PAX80 2012)