Relationship between autonomic nervous system activity during sleep and fasting glucose in Japanese workers

Although autonomic nervous system activity is reportedly related to diurnal glucose tolerance impairment, the relationship with glucose tolerance during sleep is unclear. Since work styles have recently diversified, it is important to assess the effect of sleep on workers' health. Elucidation of the relationship between autonomic nervous system activity during sleep and glucose tolerance in workers may facilitate preventive measures against diabetes using non-pharmacological means (e.g., sleep hygiene education, relaxation techniques and stress management). We examined whether autonomic nervous system activity during sleep is related to fasting glucose or glycated hemoglobin (HbA1c) in individuals with either normal or impaired fasting glucose tolerance. The subjects were 77 apparently healthy Japanese workers with normal or impaired fasting glucose. We used high frequency (HF) and the ratio of low frequency to high frequency (LF/HF) obtained by pulse wave analysis to estimate autonomic nervous system activity. The data were analyzed using a generalized estimating equation adjusted for potential confounders (age, gender, engagement in shift work, sleep duration, and body mass index). Fasting glucose was significantly negatively related to HF, the parasympathetic component during sleep. Our results suggest that parasympathetic activity during sleep is associated with fasting glucose in apparently healthy Japanese workers.