I'm a software engineer doing some research in order to figure out if developing some applications are worth the effort. This work is applied to computational devices including mobile devices and even smart houses.

I would like to know when people wake up from sleep:

  • What environmental factors influence us the most?
  • What factors, including sites and sounds, improve our mood?
  • What factors stimulate cognitive activity?
  • Do such factors vary between people?
  • 6
    $\begingroup$ I don't have enough info for a proper answer, but one of the biggest factors is light. It affects a number of internal processes, particularly relating to sleep/wake cycles. A large number of people find that waking up to light is far easier than an alarm clock. $\endgroup$
    – BenCole
    Commented May 24, 2012 at 13:08

2 Answers 2


Particulalry short wavelengths (such a UV light) have been shown to suppress melatonin[1], a hormone that regulates sleep. The authors also show that:

All subjects had an elevated cortisol level in the 90 minutes prior to onset of light exposure compared with the corresponding clock time on the previous day

So there's a kind daily memory in the diurnal system. In the case of cortisol, 555 nm (green light) affected hormone levels just as much as UV.

However, if you take people out of the sun cycles, they still maintain very close to the same cycle for some time. Michel Siffre is known for his six-month cave stay (he even kept his rectal temperature). Wiki says after a month, his cycles started to vary from 18-52 hr "days", but I've never seen that data so I can't comment. Lack of sunlight can cause mental instability, so you'd really need more controlled experiments than Siffre provided (I'm sure they're around if one digs, Siffre's work is decades old now).

Biological clocks are dominantly regulated by genetic and proteomic processes, but will take cues from the sun. However, many people can suffer a mental disorders (Seasonal Affective Disorder) from not having enough sun. In Alaska, you can buy a light to treat it during the dark winters. So the sun doesn't need to be there for the rhythm to be there, but the light can mess with the rhythm if it is there..

Other than light intensity and frequency content, sights and sounds probably don't matter much (unless of course, they're loud and wake you up, ruining your sleep schedule). What's probably most important is to have a consistent schedule and not let it get interrupted. Jet lag, interrupted sleep, drugs, alcohol, inconsistent sleeping schedules can all make waking uncomfortable.

It does vary between people. They can have a different genetic regime, but they can also have a different developmental behavior regime and/or a different environmental reigme.

[1] Steven W. Lockley, PhD1,2; Erin E. Evans, BS, RPSGT1; Frank A.J.L. Scheer, PhD1,2; George C. Brainard, PhD3; Charles A. Czeisler, PhD, MD1,2; Daniel Aeschbach, PhD. Short-Wavelength Sensitivity for the Direct Effects of Light on Alertness, Vigilance, and the Waking Electroencephalogram in Humans. SLEEP, Vol. 29, No. 2, 2006

  • 1
    $\begingroup$ Thank you so much for your answer. I think i got what i needed. So that it doesn't matter which environmental factors are there when you wake up. If they disturb your regular sleeping pattern they are going to be "annoying" . I wanted to find a pleasant way to be waken from sleep. $\endgroup$
    – bmartins
    Commented May 29, 2012 at 6:15
  • 1
    $\begingroup$ environmental factors do play some role (if you like the sea, maybe ocean waves crashing would be nice to wake up to) but it's overshadowed by routine. If you try to wake up 3 hours earlier than usual, the sea sounds aren't going to help much. When you use the SAD light in Alaska, you have to turn it on consistently at the same time every day to build up a routine. $\endgroup$ Commented May 29, 2012 at 20:21
  • $\begingroup$ The response to light takes time to set in. Check out this video for hands on methods (towards the end of the video) youtu.be/PKIqW0FScik $\endgroup$
    – Alex Stone
    Commented Apr 30, 2013 at 0:46

I've been wanting to share this study with people for a while. In my experience the light thing helps to a degree, but not as much as other concepts - it just depends on what sort of engineer you are I suppose. I think you could somehow creatively fit this into some sort of app or smart house - it depends. It might add some answer to part of your questions. The environmental part? Not so much probably. I'll just present the concept anyway - it involves nutrition.

I've used what this study concludes too and it works. It's essentially just saying "eat protein, have more energy in the morning." I know everyone says that, but I want to cite it.

Overgeneralized Preface: Tyrosine levels in the brain tend to cause the brain to make more dopamine or other types of chemicals, "catechlomines," that give a person energy. Coffee causes more of these to release in your brain. Amphetamines...much more so. Tyrosine is the building-block for these chemicals in your brain though.

Brain levels of tryptophan are the same thing except it will cause your serotonin levels to rise and make you either tired, lazy, or could have any number of affects...but most likely, in general, those that are the opposite of the catechlomines.

And thus:

Effects of normal meals rich in carbohydrates or proteins on plasma tryptophan and tyrosine ratios. Richard J Wurtman, Judith J Wurtman, Meredith M Regan, Janine M McDermott, Rita H Tsay, and Jeff J Breu + Other Author Affiliations. From the Clinical Research Center (RJW, JJW, MMR, JMM, RHT, and JJB) and the Department of Brain and Cognitive Sciences (RJW), Massachusetts Institute of Technology, Cambridge. Full text here: http://ajcn.nutrition.org/content/77/1/128.

Background: The delivery of circulating tryptophan to the brain and its conversion to serotonin vary directly with plasma concentrations of tryptophan and inversely with those of other large neutral amino acids (LNAAs). Although carbohydrate-rich, protein-free formula diets have been shown to elevate, and high-protein diets to depress, the tryptophan-LNAA ratio, few data are available about this ratio’s responses to actual meals.

Objective: We determined whether carbohydrate-rich or protein-rich breakfasts, such as those Americans normally eat, produce substantial differences in the plasma tryptophan-LNAA ratio and in the corresponding ratio for tyrosine, the precursor of brain dopamine and norepinephrine.

Design: Nine overnight-fasted subjects consumed, 3–7 d apart, a carbohydrate-rich (69.9 g carbohydrate and 5.2 g protein) and a protein-rich (15.4 g carbohydrate and 46.8 g protein) breakfast. Blood samples collected at baseline and after 40, 80, 120, and 240 min were assayed for tryptophan, tyrosine, the 5 other LNAAs, and insulin.

Results: The carbohydrate-rich and protein-rich breakfasts had significantly different effects on both the plasma tryptophan-LNAA and tyrosine-LNAA ratios (each P < 0.01). Among the 8 subjects who consumed both breakfasts, the median difference for tryptophan:LNAA was 54% (range: 36–88%) and for tyrosine:LNAA was 28% (range: 10–64%). Insulin concentrations rose significantly after the carbohydrate but not after the protein meal.

Conclusions: High-carbohydrate and high-protein breakfasts similar to those Americans normally eat can cause substantial differences in the plasma tryptophan ratio and thus, probably, in brain tryptophan concentrations and serotonin synthesis. Such meals also change the plasma tyrosine ratio and may thereby modify catecholamine synthesis.

As a general summary: if you eat a breakfast with a much higher ratio of protein to carbohydrates then you're likely to have more energy to start your day off with. Whereas if you just eat donuts for breakfast you're much more likely to fall asleep at your desk.

There are many other studies and I believe I really came across a huge one that is a derivative of this work (or vice-versa) that stated the same thing - I just don't have the time to find it although I'm sure if you look around that link at the top of the study you'll find plenty of evidence.

I know this isn't really about light or immediately when a person wakes up, but it may be another factor to consider, potentially.

It gets at the gist of part of your questions though:

What environmental factors influence us the most? What factors, including sites and sounds, improve our mood? What factors stimulate cognitive activity?

So, food and that ratio is a factor, not so much environmental...

  • $\begingroup$ I've read its impossible to be awake without serotonin and that in order to sleep, serotonin must be converted to melatonin. Is this true? Also, I was under the impression a high-sugar breakfast would cause an insulin spike, which once the sugar is gone, would then make you sleepy. Whereas protein rich meals would have more complex energy sources and not cause the spike in insulin. $\endgroup$
    – Randy
    Commented Aug 22, 2013 at 21:09
  • $\begingroup$ Yes, the dopamine/serotonin thing gets very, very, very complex. If you didn't have any serotonin you'd also not only not be awake but be dead. It's more of a balance of things. It's the ratio that matters. Yes, you do need melatonin to go to sleep - not all of it has to convert though. Yes, the insulin spike is also another factor as well in addition to the above study I cited. $\endgroup$
    – user3433
    Commented Aug 22, 2013 at 21:19
  • $\begingroup$ However, I feel that the insulin spike and fall actually overlap with what I've cited with this study in some way. This is just a theory though. Your blood glucose levels and how they're going up and down or remaining stable are a huge factor - but, once again, I feel like this is somehow connected with the above citing study. They may be independent variables with slight dependence on each other. $\endgroup$
    – user3433
    Commented Aug 22, 2013 at 21:24
  • $\begingroup$ You have to use the 'at' symbol before my name to get my attention unless you're replying to an answer or question I made. Otherwise I'll have no idea you left a comment unless I just suspect you may have and come looking. $\endgroup$
    – Randy
    Commented Aug 23, 2013 at 15:11
  • $\begingroup$ You should look into cytokines for a link to tryptophan, serotinon, etc. Cytokines somehow make use sleepy and appear in at least some instances to be related to food (as well as infection). $\endgroup$
    – Randy
    Commented Aug 23, 2013 at 15:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.