Perceived stress and associations between physical activity, sedentary time, and interstitial glucose in healthy adolescents

Abstract

Background: Less moderate to vigorous physical activity (MVPA), more sedentary time (ST), and higher perceived stress are related to type 2 diabetes mellitus (T2DM) occurrence, but observational evidence addressing the interaction of these factors is lacking in youth. This pilot study investigated momentary stress as a moderator in the acute associations of MVPA and ST with subsequent glucose in healthy adolescents.

Methods: Participants (N=15, Mage=13.1±1.0 years, 10 girls, 5 with overweight/obesity) simultaneously wore a continuous glucose monitor (CGM), thigh-mounted accelerometer, and reported momentary stress via random ecological momentary assessments (EMA; Time T) for 7-14 days. MVPA and ST (min) were calculated for 60- and 120-minute time windows before each EMA prompt (Time T-1). Mean CGM-measured interstitial glucose (mg/dL) was calculated after each prompt (Mmin=120.0±25.4; Time T+1). Multilevel models assessed whether within-subject MVPA and ST (Time T-1) predicted mean glucose (Time T+1), with momentary stress as a moderator (Time T).

Results: There were 513 time-matched EMA reports of stress, accelerometer, and CGM data. Momentary stress moderated the effects of MVPA 60 (β=-0.22, p=.001) and 120 min (β=-0.08, p=.02) before the prompt on subsequent glucose levels. When youth spent more time in MVPA than their average and when momentary stress was higher than their average, subsequent glucose was lower. Stress did not moderate associations of ST with glucose (p>.05).

Conclusions: Higher momentary stress may interact with higher MVPA to lower subsequent glucose in youth. Accelerometers, EMA, and CGMs can be integrated in future studies to further understand these associations in free-living environments.

Keywords: Activity behaviors; Psychological factors; Type 2 diabetes; Youth.

Figure 1.

Diagram of the accelerometry, EMA, and CGM measures used to derive the predictors, moderator, and outcome in this study, with example times of day to demonstrate the study timeline.

Figure 2.

Participant and data flow

Figure 3.

Plots demonstrating the moderation effect of perceived momentary stress on MVPA at 60 minutes (A), MVPA at 120 minutes (B), ST at 60 minutes (C), and ST at 120 minutes (D) before the EMA prompt on subsequent interstitial glucose level. Regression lines in the plots demonstrate the interaction effect for one standard deviation below (e.g., low perceived momentary stress, low MVPA 60 min before the EMA prompt) and above (e.g., high perceived momentary stress, high MVPA 60 min before the EMA prompt) the mean. Plots were created using two-way interaction templates from http://www.jeremydawson.co.uk/slopes.htm.