1. Stress
When you have one or more stress peaks throughout the day, your body secretes adrenaline and cortisol. These hormones increase the heartbeat. Factors that precipitate sleep disturbances and can even cause anxiety, a disorder that can be chronic.
2. a change in working hours
If you work alternating day and night shifts, your sleep can be impacted. When you get used to a rhythm of work, your nights take a beating and this creates sleep disturbances and this impacts the biological clock. If your time slots vary during the month, this is probably the reason why you are sleeping poorly.