Circadian rest-activity rhythm for maintenance of body shape.

A recently developed wearable device has gained attention in the area of self-discipline for the prevention of lifestyle-related diseases. The present study aimed to clarify the relationship between circadian rhythm and body shape change using actigraphy. Using a body shape vector, we classified 24 women in their 40s and 50s into 3 groups with different body shape changes. A circadian rhythm experiment was conducted on weekdays for 1 week with 24 healthy women. Amounts of activity of the non-dominant wrist and trunk, subjective evaluation of sleep quality, and subjective state of activity were surveyed. In order to maintain a constant body shape throughout life, a less sedentary lifestyle with more trunk movement during the day, getting adequate sleep at night, and having a varied sleep-wake cycle may be important factors.