Can the early bird catch the worm? Effects of early rising on leukocyte subsets via modification of autonomic nervous system and the effect on glucose levels

The importance of sleep has been described in proverbs such as “the early bird catches the worm”. However, there are few scientific reports on the effects of early rising. Therefore, early risers (Group E) and late risers (Group L) were compared and the number and ratio of leukocytes, body temperature, glucose and its associated hormones were studied. Furthermore, each group was divided into two groups by the duration of sleep and the following four groups were compared: early risers with short sleep (Group E-S); early risers with long sleep (Group E-L); late risers with short sleep (Group L-S); and late risers with long sleep (Group L-L). Then, compared with Group L, Group E showed lower numbers and ratio of granulocytes and a higher ratio of lymphocytes showing parasympathetic nerve dominance. Group E showed higher levels of glucose and its related hormones than Group L, indicating sympathetic nerve dominance. Compared with Groups E-S and L-S, Groups E-L and L-L showed lower glucose and cortisol levels, respectively. These results indicated that early rising might affect leukocyte subsets, and adequate duration of sleep could decrease levels of glucose via modification of the autonomic nervous system.