Sleep and Temperature


Recommending a specific range is difficult, Downey and Heller say, because what is comfortable for one person isn’t for another (explaining how Roy’s wife slept blissfully in the chilly 60-degree room). While a typical recommendation is to keep the room between 65 and 72 degrees Fahrenheit, Heller advises setting the temperature at a comfortable level, whatever that means to the sleeper.

Doheny, K. (2010). Can’t Sleep? Adjust the Temperature. WebMD. Retrieved August 31, 2014, from

Looking at the available research, most studies agree that a temperature between 60 and 67 degrees Fahrenheit is optimal for sleeping, with temperatures above 75 degrees and below 54 degrees disruptive to sleep.[][] Body temperature has also been linked to the amount of deep sleep an individual gets during the night, with cooler body temperatures leading to more deep sleep.[][] Sleeping in a hot environment has also been shown to increases wakefulness and decreases slow wave sleep. The addition of high humidity can intensify the effect of heat.[]

Winter, C. (2013, October 10). Choosing the Best Temperature for Sleep. Huffington Post. Retrieved August 31, 2014 from,

“Temperature regulation is a significant factor in each of the two types of insomnia. The difference is when the insomnia occurs. People with sleep onset insomnia have difficulty initiating sleep at the beginning of the night, taking two to four hours each night in the worst cases….”

“Studies of sleep onset insomniacs show that they consistently have a warmer core body temperature immediately before initiating sleep, when compared with normal healthy adults. This results in a state of heightened arousal that prevents them from falling asleep when they go to bed, probably because they have to wait for their bodies to lose the heat that’s keeping them awake. We’re only talking about a half to one degree but that small temperature change can result in significant differences in arousal between insomniacs and people without sleeping problems,” Dr Van den Heuvel says.

Hinter, G. (2004). Getting to the core of insomnia. UniSANews. Retrieved August 31, 2014 from

Studies have found that in general, the optimal temperature for sleep is quite cool, around 60 to 68 degrees Fahrenheit. For some, temperatures that fall too far below or above this range can lead to restlessness.

O’Connor, A. (2009, August 3). The Claim: Cold Temperatures Improve Sleep. Retrieved August 31, 2014 from

Extreme temperatures at either end of the range can affect sleep. A hot room (more than 24° C [75.2° F]) can cause restless body movements during sleep, more nighttime awakenings, and less dream type sleep. A cold room (less than 12° C [53.6° F]) can make it difficult to get to sleep and can cause more unpleasant and emotional dreams. We recommend room temperature to help promote sleep for most people is, therefore, around 18° C [64° F].

Morin, C.M. (2003, June 30). Insomnia: A Clinician’s Guide to Assessment and Treatment. Springer Science & Business Media. p. 51.

Research shows that the ideal temperature range for sleeping varies widely among individuals, so much so that there is no prescribed best room temperature to produce optimal sleep patterns. People simply sleep best at the temperature that feels most comfortable. That said, extreme temperatures in sleeping environments tend to disrupt sleep. REM sleep is commonly more sensitive to temperature-related disruption. For example, in very cold temperatures, we may be deprived entirely of REM sleep.

Division of Sleep Medicine at Harvard Medical School. (2007). External Factors that Influence Sleep. Retrieved August 31, 2014 from

Image credit: Kiyo and Jean-Paul

Onen SH, Onen F, Bailly D, Parquet P. Prevention and treatment of sleep disorders through regulation of sleeping habits. Presse Med.1994; Mar 12; 23(10): 485-9.
National Sleep Foundation: The Sleep Environment
Murphy PJ, Campbell SS. Nighttime drop in body temperature: a physiological trigger for sleep onset? Sleep. 1997 Jul; 20(7): 505-11.
Jordan J, Montgomery I, Trinder J. The effect of afternoon body heating on body temperature and slow wave sleep. Psychophysiology. 1990 Sep; 27(5): 560-6.
Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. J Physiol Anthropol. 2012 May 31; 31: 14.

Rosemary Bread Machine Bread

Makes a 1 \frac{1}{2}-pound loaf

  • 1 cup warm water (110 degrees F (43 degrees C))
  • 2 \frac{1}{2} teaspoons active dry yeast
  • 3 tablespoons white sugar
  • 1 \frac{1}{2} teaspoons salt
  • 3 tablespoons olive oil
  • \frac{1}{2} teaspoon ground thyme
  • \frac{1}{2} teaspoon garlic powder
  • 2 teaspoons crushed dried rosemary
  • 3 cups all-purpose flour

Pour the water into the pan of a bread machine, then sprinkle in the yeast and sugar. Let the mixture sit in the bread machine until a creamy foam forms on top of the water, about 10 minutes. Sprinkle in the salt, then add olive oil, thyme, garlic powder, rosemary, and flour. Set the machine for light crust setting, and start the machine.

(Possibly Useful) Information Concerning McDonald’s Large Fries

USA McDonald’s Large Fries
Serving Size: 168g
Calories: 510
Calories from Fat: 220
Total Fat: 24g



UK McDonald’s Large Fries
Serving Size: 150g
Calories: 430
Calories from Fat: 196
Total Fat: 21g



Percentage of McDonald’s Fries that is Potato/Fat

86% potato
14% vegetable oil (aka, fat)



Number of Potatoes in Large McDonald’s Fries

168 (number of grams in large McDonald’s fries)
.86 (proportion of fries that is potato)
= 144.48g

* * *

Medium Potato
Serving Size: 148g
Calories: 110
Calories from Fat: 0
Total Fat: 0g


* * *

1 large McDonald’s french fries order contains about
1 medium potato.


Evidence that Fat and Oil are Roughly Equivalent

Lucini Olive Oil
Serving Size: 14.3g (1 Tbsp)
Calories: 120
Calories from Fat: 120
Total Fat: 14g


Herbert Hoover

I started researching the presidents to be more helpful at team trivia. In doing so, I learned more about the impressive Herbert Hoover. After watching a PBS documentary about his work feeding Russians in the 1920s, I ended up stumbling across an Oregon-based Hoover scholar named Finn John. Here’s an exchange I had with him about 3 years ago:

Mr. John,
I’m glad to have stumbled across your nice blog with info regarding Herbert Hoover. I recently saw the PBS American Experience treatment of the 1921 Russian famine and was very moved by Hoover’s actions. As I was perusing your notes regarding Hoover’s famine assistance, I noticed that you say that the actual number of Hoover’s “life toll” is “…certainly no lower than 500 million.” I am curious to know how you arrived at this figure. From what I understand, the ARA was feeding around 11 million Russians a day at its peak. I’m less sure of how many people were fed in Belgium, Poland, Austria and wherever else. The only total “life toll” I’ve seen aside from yours is one from Hoover biographer George Nash: 83,000,000.

I am curious to know what you think of that.


* * *

Hi Clifton, the half-billion figure was kind of a gut-level guess. Nobody really knows for sure. In his memoirs Hoover himself put the figure at 1.4 billion, which seems excessive, and he doesn’t say how he got there.

The 500 million would include 9 million in Belgium, around 230 million in eastern Europe after World War I via the ARA, the 11 million in Russia (who probably represented a larger number than that, as it wasn’t necessarily the same 11 million every day) and another nine-figure number of Europeans fed after World War II at the behest of Harry Truman.

It’s sure an amazing story. The PBS documentary was excellent. It’s odd to think about it this way, but for Hoover, being President of the United States was not his crowning achievement — it was almost a step down. I can’t think of any other ex-presidents for whom that was the case.

Anyway, thanks for the note! I love talking about this stuff, as you’ve probably noticed …



* * *

Happy birthday to Herbert Hoover, scientist, fluent speaker of Mandarin Chinese, and one of history’s greatest humanitarians.

Kernel Panic on OS X Update

I recently read of someone’s attempt to update a ProBook 4530s from Mavericks 10.9.3 to 10.9.4. They wrote that the install went smoothly, but, on reboot, they got a kernel panic. Mixed in with the textsplosion that filled the screen was a reference to “AppleIntelCPUPowerManagement.” It looked something like this:

KernalPanic AppleIntelCPUPowerManagement

This screen could not be bypassed by booting into the installed OS from the person’s USB drive. They could only run the OS X installer and use a fix from Terminal. The person ended up finding this fix on the blog of Sanga Collins.

  1. Enter your boot menu via the BIOS.
  2. Start the OS X installer (using a DVD or USB drive) and then open Terminal.
  3. Select your language.
  4. Click “Continue” at the welcome message.
  5. Click “Agree” when asked.
  6. At the “Select Destination” screen, go to the Utilities menu and select Terminal.
  7. When the terminal window opens type:
    • cd /Volumes/[HardDisk–Or whatever your install is called.]/System/Library/Extensions
    • rm -rf AppleIntelCPUPowerManagement.kext
  8. Quit Terminal.
  9. Quit the installer and reboot.