The Link between Hair Cortisol Levels and Physical Activity in a Study of Young Adolescents

Denman Research Forum 2018: Second Place in the Cognitive and Brain SciencesThis study explored associations between different levels of physical activity and cortisol levels in hair among adolescents. Although research has found that physical activity can be beneficial for reducing illness and stress in populations, studies have found a correlation between strenuous physical activity and elevated salivary and hair cortisol levels. This study employs secondary analysis of data from a representative sub-sample of 534 adolescents aged 11 to 17 years who participated in two linked NIH funded studies on the health and well-being of urban adolescents. Through an in-home survey, youth were asked three questions on the intensity and volume of physical activity from the previous week, rating from mild to strenuous physical activity, and the number of days the activity was done. The three variables – mild, moderate and strenuous activity - were analyzed via regression analyses as continuous measures to assess linear associations. No significant linear relationships were found with this analysis, therefore the recommended reference range of exercising 6-7 times a week was compared to exercise categories based on frequency of activity (never, 1-3 times weekly, 4-5 times weekly, and 8 or more times weekly) . The results found that hair cortisol levels were significantly higher in adolescents who strenuously exercised eight times or more a week in comparison to those who strenuously exercised 6-7 hours per week as recommended(p