Health and Well-being: Lecture 4 - Part 2, Light health and well being (NON image forming) Flashcards
Mention two accute effects of the retinohypothalamic tract, and two longer-term effects
Acute: Melatonin secretion Body temperature Cortisol secretion Alertness Heart rate Cognitive performance
Longer term:
Circadian regulation
Light therapy
To where do the ipRGCs connect?
Supra chiasmatic nuclei (SCN), which projects to the pineal gland (epifyse): biological clock
What are entrainment effects of light?
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
On what aspects of light does circadian rhythm depend?
Intensity Timing Duration Internal time Spectrum of light
What do are stimulus effect curves also called?
Dose respons curve
What do phase response curves show?
Delay or advancing of sleep because of light
What happens when eyes are exposed to light in the middle of the night?
Melatonin secretion almost immediately stops
When does light probably exert its most alerting action?
When the circadian drive for sleep is at the maximum
When under high homeostatic sleep pressure
During sleep inertia
Alerting effects are … dependent
wavelength
When is melanopsin ipRGC maximally sensitive?
At 480 nm
What is a chronotype?
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
What is midsleep?
Midsleep is the moment in the middle between when you go to sleep and when you wake up
Why is there a peak around 8 on work days, and not on free days for sleep?
Because on work days everyone needs to get out to go to work, school, etcetera
Why is life though for late chronotypes?
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
Why do people misentrain?
Exposure patterns Lack of light Too much light Social jetlag Chronotype Jetlag Shiftwork Visual impairment and more...
Can you explain why technology has decouples us from the 24 hour day to which our bodies evolved?
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
Why do we wake later than peope in Berlin even though we live on the same height?
The sun rises earlier in Berlin than in the Netherlands, so we wake later
Why are big cities always colored red for midsleep measures?
Because in cities there are always effects of electrical lighting during the night
What is seasonal affective disorder?
Affective and behavioral problems in autumn and winter with remission in spring and summer
When do people search most often for depression in google?
When temperatures are lowest, so during winter
Seasonal affective disorder vs non-seasonal depression. What are typical sumptoms of both, and what are atypical symptoms?
Typical
- Lethargy, depressed mood
Hypersomnia (excessive sleeping) and weight gain vs insomnia and weight loss
What is photoperiod?
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
What are behavioral mechanisms of SAD?
Behavioral disengagement
Reduced activity enjoyment in autumn
Reduced activity frequency in winter
Treatment for SAD:
Light therapy
2500-10000 lux bright white light
Timing important related to internal time
Going outdoors helps
What is s-SAD
A milder form of the seasonal affective disorder
Name three effects of light in recovery surgery room:
Bright light decreased:
Perceived stress
Perceived pain
Use of pain medication
Where are in the world are more ADHD cases?
In places where there is less sun..
Light helps against multiple diseases such as:
non seasonal depression ADHD eating disorders dementia parkinsons burnout
What two things lead to improper entrainment between internal circadian rhythm and external 24h cycle?
The Zeitgeber strength (too much light, not enough, light at longer wavelenghts)
Light at inappropriate times during biological night
