Background: More screen time (ST) is associated with dysregulation of the individual biological systems (cardiovascular, immune, metabolic, and neuroendocrine) involved in the stress response in youth. However, its relationship with allostatic load (AL), a measure of the cumulative physiological stress response, is unclear in youth.
Purpose: To investigate the associations between ST types and AL outcomes in youth and to explore sociodemographic and behavioral moderators of these relationships.
Methods: Cross-sectional data were from 1053 US youth aged 12-17 years (Mage = 14.20; 54% male; 21% Hispanic) in the 2015-2018 National Health and Nutrition Examination Survey (NHANES). ST was assessed as watching TV/videos and computer use/playing computer games. AL was measured using 7 biomarkers across 3 systems: cardiovascular (systolic and diastolic blood pressure, heart rate), immune (C-reactive protein), and metabolic (body mass index, glycohemoglobin, and high-density lipoprotein). Weighted multivariable regression models assessed whether ST predicted AL composite and subsystem (cardiovascular, immune, and metabolic) scores. Moderation by age, sex, income, race/ethnicity, and physical activity was explored.
Results: A 1-hour/day increase in watching TV/videos was associated with a 4% increase in mean AL composite score (incident rate ratio = 1.040; 95% CI = 1.008, 1.073; P = .015), while computer use/gaming showed no significant associations (P's > .05). Age moderated the TV/videos-AL cardiovascular association (P = .009), with older youth having higher AL cardiovascular scores.
Conclusions: More time spent watching TV/videos was associated with higher cumulative physiological stress in youth. Prospective studies are needed to determine causal pathways and potential intervention targets in youth.
Keywords: adolescent; biomarkers; computer; physiological stress; sedentary; television.
Screen time (ST) behaviors, such as watching TV, using the computer, or playing video games, are common among youth. ST behaviors are linked to several health concerns, but it not clear how they affect physiological stress. This study examined how different types of ST affected allostatic load (AL), a summary measure of combined physiological stress across several body systems, among US youth aged 12-17 years. We found that more time spent watching TV or videos was associated with higher AL, suggesting that this behavior leads to higher overall stress-related wear and tear on the body. However, computer use or gaming did not show a relationship with AL. We also found that in older adolescents with a lot of TV or video ST, there was more stress in the cardiovascular system. These findings for the first time show that certain ST behaviors can influence physiological stress even in youth. More research is needed to understand the mechanisms beneath these relationships and how we should intervene to promote health and prevent disease.
© The Author(s) 2025. Published by Oxford University Press on behalf of the Society of Behavioral Medicine.