Behavioural and Biological Predictors of Stress: Sleep, Growth Factors, and Sex

Abstract

Sleep disturbances are prevalent among young adults and have been linked to impaired stress regulation and mood. It is possible that growth factors including brain-derived neurotrophic factor (BDNF) and fibroblast growth factor-21 (FGF-21) play a role in the sleep-mood connection. However, this has rarely been examined, particularly according to sex. Participants aged 17-29 ( N =237; 56 males, 181 females) were randomly assigned to the Trier Social Stress Test (TSST) or control condition. Baseline measures included sleep quality, perceived stress and anxiety, and blood samples were collected for BDNF and FGF-21 quantification. Post-stressor state anxiety and affect were also assessed. Poorer subjective sleep was associated with higher perceived stress and anxiety (ps<0.05). Females reported greater fatigue, early awakening, tiredness, and post-stressor state anxiety than males (ps<0.05). Higher FGF-21 was associated with greater tiredness (p=0.01), longer sleep duration (p=0.013), and oversleeping in females (p=0.032), whereas lower FGF-21 was associated with longer sleep duration (p=0.049) and early awakening in males (p=0.028). BDNF was associated with greater fatigue in males only (p=0.024). Although sex and FGF-21 predicted state anxiety (p=0.043) and fear responses to the TSST (p<0.001), respectively, tiredness emerged as the strongest predictor of both outcomes (p<0.001). These findings suggest that sleep quality is an important contributor to stress responsivity, with growth factors and sex further influencing these relationships among young adults.