ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Sleep, Circadian Rhythms and Caffeine

Updated on October 10, 2015

Even Santa Needs Coffee!

No Known Copyright Restrictions - Flikr Commons
No Known Copyright Restrictions - Flikr Commons | Source

Can't Sleep? Too much Coffee?

Ever wondered what it is that regulates our sleep patterns? What is all that tea and coffee is doing to us? Why do so many people have so much trouble getting to sleep? (There are some great hubs about sleep disturbances and I will include links to them below.) As many people already know, the side effects of too much coffee and tea can be debilitating and even harmful to health and well being. But is the problem about how much we consume or the pattern of consumption? Should we be drinking small amounts of caffeine throughout the day or should we stick with the 'big jolt in the morning' model?

On Insomnia

Goodbye Insomnia, Hello Sleep
Goodbye Insomnia, Hello Sleep

Growing interest in the field of sleep research and its accompanying increased clinical observation has led to a better understanding of insomnia, a problem affecting half of our adult citizens.


Caffeine Effects

Caffeine is one of the three most widely used drugs in the world (the others are nicotine and alcohol). The human body reacts almost instantly to caffeine. The speed and intensity of the reaction to caffeine depends on a person's weight and other physiological factors and is a very individual thing. Caffeine stays in your blood for around 12 hours after ingestion. It is a mood affecting drug as well as having physical side effects. Caffeine:

  • makes your heart rate go up;
  • stimulates your central nervous system (CNS);
  • affects your breathing;
  • elevates mood;
  • decreases fatigue;
  • causes your stomach to produce more acid;
  • can result in in increased urination (diuretic affect);
  • can alter blood sugar levels;
  • increases blood circulation;
  • elevates blood pressure;
  • elevates the levels of fatty acids in your blood;
  • can create restlessness and irritability;
  • can result in difficulty concentrating;
  • causes caffeine dependence;
  • can result in miscarriages and birth difficulties (with heavy usage);
  • can cause an increase in breast tenderness; and
  • can result in insomnia.

In the worst case scenario caffeine can contribute to heart rhythm disorders, prolonged or chronic depression and panic attacks. It is no surprise that heavy caffeine usage has been liked to high blood pressure, oesteoperosis, insomnia, heartburn, ulcers and even infertility.

On the positive side, there is some evidence that caffeine can also result in a reduced risk of developing heart disease.

Letterman's '10 Signs you Drink too much Coffee'

 Creative Commons Attribution-Share Alike 2.0 Generic Licence
Creative Commons Attribution-Share Alike 2.0 Generic Licence | Source

Caffeine Sources

The number one offender is coffee with anywhere from 60-500 milligrams of caffeine per cup depending on whether it is instant, espresso, percolated or filter coffee. Tea has approximately 35-40 milligrams. Other sources of caffeine include:

  • Chocolate;
  • Soft drinks;
  • Energy drinks;
  • Some vitamin compounds; and
  • Some medications.

More on Insomnia

The Insomnia Solution: The Natural, Drug-Free Way to a Good Night's Sleep
The Insomnia Solution: The Natural, Drug-Free Way to a Good Night's Sleep

To relieve stress and ensure sounder sleep, Krugman offers a two-pronged program of gentle, physical techniques, called Mini-Moves, based on traditional and modern self-healing methods including qigong, meditation, and the Feldenkrais Method. Brief, daytime Mini-Moves offset stress and make life more peaceful. When your life is more peaceful, your sleep is more peaceful.


Circadian Rhythms

Your circadian rhythm is governed by the physical, behavioural and mental changes that occur in relation to light and darkness over an approximate 24 hour period. The circadian rhythm is driven by the biological clock which is in turn driven by about 20,000 nerve cells in the hypothalamus in the brain. Circadian rhythms can cause alterations in sleep-wake cycles, temperature and hormone release among other things.

The relationship between circadian rhythms and sleep-wake cycles is regulated by the production of the hormone melatonin. The hypothalamus is located near the optic nerve and the amount of light will in turn stimulate or decrease melatonin production which influences how drowsy a person is.

Coffee and Tea Jolt

Do you use caffeine to jolt you into action?

See results

How does Caffeine Affect Sleep and Circadian Rhythms?

We all know that caffeine keeps you awake. However, scientists still do not know the exact answer to the question of why this is so. While they know that caffeine works by interfering with two interacting systems (the homeostatic system and the circadian clock) that regulate the sleep-wake cycle, they do not know exactly how it achieves this. They think that caffeine blocks the actions of a messenger chemical - adenosine (which sends messages to the homeostatic system to induce sleep). Adenosine is a powerful natural sleep inducing chemical. It seems that caffeine has a more powerful effect on the homeostatic system than on the circadian clock.

If caffeine does block adenosine, the logical inference is that caffeine can allow people to take control of their sleep patterns, defying their circadian clocks. This is a good thing for shift-workers and global travellers but it seems that few people know how to do this effectively.


Wikimedia Commons: No copyright restrictions
Wikimedia Commons: No copyright restrictions | Source

Big Jolt of Caffeine v Small Frequent Doses

Scientists have done surveys on shift-workers that show that it is far better to have small amounts of caffeine throughout the day than a big hit in the morning. The test subjects who took low dose frequent caffeine did better on cognitive testing, although they apparently did continue to feel sleepy.

I know that I feel as though I need that caffeine hit in the morning to get me going. I also know that come early afternoon I am flagging and the screen gets a bit hazy. I might take their advice and drink a third of a cup frequently instead of about three cups before 10am and none after then. 

Caffeine Quiz

view quiz statistics


Much of this information was obtained from the following:

  • Harvard Medical School (2004, May 12). Small, Frequent Doses Of Caffeine Best Strategy For Staying Awake, According To New Study.
  • National Geographic Magazine, (January 2005). Caffeine: it's the worlds most popular psychoactive drug.
  • National Institute of General Medical Sciences (July 2008) Circadian Rhythms Fact Sheet.


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)