Health and Well-being: Lecture 4 - Part 2, Light health and well being (NON image forming)

Question 1

Mention two accute effects of the retinohypothalamic tract, and two longer-term effects

Answer 1

Acute:
Melatonin secretion
Body temperature
Cortisol secretion
Alertness
Heart rate
Cognitive performance

Longer term:
Circadian regulation
Light therapy

Question 2

To where do the ipRGCs connect?

Answer 2

Supra chiasmatic nuclei (SCN), which projects to the pineal gland (epifyse): biological clock

Question 3

What are entrainment effects of light?

Answer 3

Entrainment effects of light are time-dependent
Under natural conditions, the endogenous oscillator is entrained to a true 24 h period by environmental signals
Not all clocks run in sync
The essence is that each of us maintain a stable phase relationship with earth’s rotation

Question 4

On what aspects of light does circadian rhythm depend?

Answer 4

Intensity
Timing
Duration
Internal time
Spectrum of light

Question 5

What do are stimulus effect curves also called?

Answer 5

Dose respons curve

Question 6

What do phase response curves show?

Answer 6

Delay or advancing of sleep because of light

Question 7

What happens when eyes are exposed to light in the middle of the night?

Answer 7

Melatonin secretion almost immediately stops

Question 8

When does light probably exert its most alerting action?

Answer 8

When the circadian drive for sleep is at the maximum
When under high homeostatic sleep pressure
During sleep inertia

Question 9

Alerting effects are … dependent

Answer 9

wavelength

Question 10

When is melanopsin ipRGC maximally sensitive?

Answer 10

At 480 nm

Question 11

What is a chronotype?

Answer 11

Chronotypes refer to the behavioral manifestation of underlying circadian rhythms.Chronotype is the propensity for an individual to fall asleep at a particular time in a 24 hour period

Question 12

What is midsleep?

Answer 12

Midsleep is the moment in the middle between when you go to sleep and when you wake up

Question 13

Why is there a peak around 8 on work days, and not on free days for sleep?

Answer 13

Because on work days everyone needs to get out to go to work, school, etcetera

Question 14

Why is life though for late chronotypes?

Answer 14

Wake up times stay the same during workdays, however, they have to wake up very early because its a normal day/ They have hard times falling asleep and have to wake early. Sleep in on free days, and shortened sleep during weekdays

Question 15

Why do people misentrain?

Answer 15

Exposure patterns
Lack of light
Too much light
Social jetlag
Chronotype
Jetlag
Shiftwork
Visual impairment
and more...

Question 16

Can you explain why technology has decouples us from the 24 hour day to which our bodies evolved?

Answer 16

We sleep about 2 hours less than 50 years ago.
Overall light dosage is lower than in rural areas.
Insufficient light during the day (indoor work)
Too much light during the night (LED screens, street lighting etc)
We make ourselves extreme chronotypes

Question 17

Why do we wake later than peope in Berlin even though we live on the same height?

Answer 17

The sun rises earlier in Berlin than in the Netherlands, so we wake later

Question 18

Why are big cities always colored red for midsleep measures?

Answer 18

Because in cities there are always effects of electrical lighting during the night

Question 19

What is seasonal affective disorder?

Answer 19

Affective and behavioral problems in autumn and winter with remission in spring and summer

Question 20

When do people search most often for depression in google?

Answer 20

When temperatures are lowest, so during winter

Question 21

Seasonal affective disorder vs non-seasonal depression. What are typical sumptoms of both, and what are atypical symptoms?

Answer 21

Typical
- Lethargy, depressed mood

Hypersomnia (excessive sleeping) and weight gain vs insomnia and weight loss

Question 22

What is photoperiod?

Answer 22

Photoperiod is the duration of an organisms daily exposure to light
Photoperiod is the most salient environmental stressor related to SAD onset and severity, but the exact mechanism is unknown

Question 23

What are behavioral mechanisms of SAD?

Answer 23

Behavioral disengagement
Reduced activity enjoyment in autumn
Reduced activity frequency in winter

Question 24

Treatment for SAD:

Answer 24

Light therapy
2500-10000 lux bright white light

Timing important related to internal time
Going outdoors helps

Question 25

What is s-SAD

Answer 25

A milder form of the seasonal affective disorder

Question 26

Name three effects of light in recovery surgery room:

Answer 26

Bright light decreased:
Perceived stress
Perceived pain
Use of pain medication

Question 27

Where are in the world are more ADHD cases?

Answer 27

In places where there is less sun..

Question 28

Light helps against multiple diseases such as:

Answer 28

non seasonal depression
ADHD
eating disorders
dementia
parkinsons
burnout

Question 29

What two things lead to improper entrainment between internal circadian rhythm and external 24h cycle?

Answer 29

The Zeitgeber strength (too much light, not enough, light at longer wavelenghts)
Light at inappropriate times during biological night