Eating during the biological night is associated with nausea

Area of Science:

• Chronobiology
• Human Physiology
• Gastroenterology

Background:

• Circadian rhythms influence various physiological processes, including appetite and gastrointestinal function.
• Understanding the temporal patterns of subjective experiences like nausea is crucial for optimizing human health and performance.
• Previous research has explored circadian influences on bodily sensations, but specific timing of nausea requires further investigation.

Purpose of the Study:

• To determine if nausea reports exhibit a time-of-day effect.
• To investigate the relationship between circadian phase and the occurrence of nausea.
• To identify specific periods when nausea is more prevalent.

Main Methods:

• Nausea ratings were collected using visual analog scales in 34 participants during forced desynchrony studies with varied meal schedules.
• Subjective nausea reports were gathered from 81 participants in constant routine studies with hourly isocaloric snacks.
• Data were analyzed to identify patterns in nausea occurrence relative to circadian phase and time of day.

Main Results:

• Nausea intensity and frequency varied significantly with circadian phase in forced desynchrony studies, peaking during the biological night.
• In constant routine studies, 27% of participants reported nausea, typically starting several hours after their usual sleep midpoint.
• Nausea onset was notably absent during evening hours (4-9 PM) in the constant routine protocol.

Conclusions:

• Nausea is predominantly experienced during the biological night and early morning hours.
• Findings are particularly relevant for individuals working overnight or early morning shifts.
• Strategic meal timing may serve as a viable method to mitigate nausea during these vulnerable circadian phases.