Effects of Afternoon and Evening Light on Teenagers' Melatonin Levels, Alertness, Sleepiness and Sleep

Summary

Many teenagers are familiar with this: on school days, they have to get up early; during the day, they hardly get any light exposure; in the evening, they go to bed late - and are then tired at school the next day! Around the world, teenagers are sleep deprived, with studies suggesting that almost half (\~45%) suffer from inadequate sleep. Previous investigations have shown that people's sleep-wake rhythm is related to the light conditions that they are exposed to during the day and at night. However, little is known about how different light levels in the afternoon can modulate teenagers' sleep and their bodily responses to light in the late evening. Therefore, the investigators aim to study which lighting conditions have a favourable effect on these aspects and how the potentially harmful effects of light at night can be prevented.

Conditions

• Healthy
• Teenager
• Healthy Lifestyle

Interventions

OTHER

Dim light condition

During the "Dim" light condition, the four-hour afternoon light exposure at the participants' eye level will be dim (\<5 lx melanopic EDI). In the 4.5-hour evening light exposure, this will constitute a light intensity of \~100 lx melanopic EDI at the participants' eye level.

OTHER

Moderate light condition

During the "Moderate" light condition, the four-hour afternoon light exposure at the participants' eye level will be dim (\~100 lx melanopic EDI). In the 4.5-hour evening light exposure, this will constitute a light intensity of \~100 lx melanopic EDI at the participants' eye level.

OTHER

Bright light condition

During the "Bright" light condition, the four-hour afternoon light exposure at the participants' eye level will be dim (\>1000 lx melanopic EDI). In the 4.5-hour evening light exposure, this will constitute a light intensity of \~100 lx melanopic EDI at the participants' eye level.

Sponsors & Collaborators

• University Psychiatric Clinics Basel

  lead NETWORK

Principal Investigators

• Christian Cajochen, PhD · Centre for Chronobiology, University Psychiatric Clinics Basel, Basel, Switzerland

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

14 Years

Max Age

17 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2022-09-22

Primary Completion

2023-06-20

Completion

2023-06-20

Countries

• Switzerland

Study Locations