Living against the clock: Does loss of daily rhythms cause obesity?
When Thomas Edison tested the first light bulb in 1879, he could never have imagined that his invention could one day contribute to a global obesity epidemic. Electric light allows us to work, rest and play at all hours of the day, and a paper published this week in Bioessays suggests that this might have serious consequences for our health and for our waistlines.
Daily or "circadian" rhythms including the sleep wake cycle, and rhythms in hormone release are controlled by a molecular clock that is present in every cell of the human body. This human clock has its own inbuilt, default rhythm of almost exactly 24 hours that allows it to stay finely tuned to the daily cycle generated by the rotation of the earth. This beautiful symmetry between the human clock and the daily cycle of the Earth's rotation is disrupted by exposure to artificial light cycles, and by irregular meal, work and sleep times. This mismatch between the natural circadian rhythms of our bodies and the environment is called "circadian desynchrony".
The paper, by Dr. Cathy Wyse, working in the chronobiology research group at the University of Aberdeen, focuses on how the human clock struggles to stay in tune with the irregular meal, sleep and work schedules of the developed world, and how this might influence health and even cause obesity.
"Electric light allowed humans to override an ancient synchronisation between the rhythm of the human clock and the environment, and over the last century, daily rhythms in meal, sleep and working times have gradually disappeared from our lives," said Wyse. "The human clock struggles to remain tuned to our highly irregular lifestyles, and I believe that this causes metabolic and other health problems, and makes us more likely to become obese".
"Studies in microbes, plants and animals have shown that synchronisation of the internal clock with environmental rhythms is important for health and survival, and it is highly likely that this is true in humans as well".
The human clock is controlled by our genes, and the research also suggests that some people may be more at risk of the effects of circadian desynchrony than others. For example, humans originating from Equatorial regions may have clocks that are very regular, which might be more sensitive to the effects of circadian desynchrony.
Shiftwork, artificial light and the 24-hour lifestyle of the developed world mean that circadian desynchrony is now an inevitable part of 21st century life. Nevertheless, we can help to maintain healthy circadian rhythms by keeping regular meal times, uninterrupted night-time sleep in complete darkness, and by getting plenty of sunlight during daylight hours.
Dr. Wyse believes that circadian desynchrony affects human health by disrupting the systems in the brain that regulate metabolism, leading to an increased likelihood of developing obesity and diabetes.
"The reason for the relatively sudden increase in global obesity in the developed world seems to be more complicated than simply just diet and physical activity. There are other factors involved, and circadian desynchrony is one that deserves further attention".
"Our 24-hour society has come at the high price of circadian desynchrony," concluded Wyse. "There are many factors driving mankind towards obesity but disrupted circadian rhythms should be considered alongside the usual suspects of diet and exercise".
More information: Wyse. C, "Does Human Evolution in different latitudes influence susceptibility to obesity via the circadian pacemaker?" BioEssays, August 2012, Wiley, DOI: 10.1002/bies.201200067
Journal reference: BioEssays
Provided by Wiley
- Circadian rhythm-metabolism link discovered Jul 24, 2008 | not rated yet | 0
- Phase of clock gene expression in human leukocytes correlates with habitual sleep timing May 01, 2008 | not rated yet | 0
- The clock watcher: Circadian rhythms research is shedding light on the causes of disease and aging May 29, 2009 | not rated yet | 0
- Finding mechanism behind bacteria's biological clock Aug 31, 2011 | not rated yet | 0
- Researchers observe disruptions of daily rhythms in Alzheimer's patients' brains Apr 27, 2011 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Why is zone 1 in liver more prone to ischemic injury?
May 23, 2013 Hi, Is it because around central vein, there is only deoxygenated blood from the vein where as in the periphery there is hepatic artery. Also why...
How can there be villous adenoma in colon, if there are no villi there
May 22, 2013 As title suggest. Thanks :smile:
How can there be a term called "intestinal metaplasia" of stomach
May 21, 2013 Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
- More from Physics Forums - Medical Sciences
More news stories
By discovering the new mechanism by which estrogen suppresses lipid synthesis in the liver, UC Irvine endocrinologists have revealed a potential new approach toward treating certain liver diseases.
Medical research May 23, 2013 | 5 / 5 (1) | 0 |
Aortic arch pulse wave velocity, a measure of arterial stiffness, is a strong independent predictor of disease of the vessels that supply blood to the brain, according to a new study published in the June issue the journal ...
Medical research May 23, 2013 | not rated yet | 0
Since the discovery of Prontosil in 1932, sulfonamide antibiotics have been used to combat a wide spectrum of bacterial infections, from acne to chlamydia and pneumonia. However, their side effects can include serious neurological ...
Medical research May 23, 2013 | 3 / 5 (1) | 0 |
Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as ...
Medical research May 23, 2013 | 5 / 5 (3) | 0 |
Spanish researchers have discovered that the daily clearance of neutrophils from the body stimulates the release of hematopoietic stem cells from the bone marrow into the bloodstream, according to a report published today ...
Medical research May 23, 2013 | 5 / 5 (2) | 0
Coenzyme Q10 decreases all cause mortality by half, according to the results of a multicentre randomised double blind trial presented today at Heart Failure 2013 congress. It is the first drug to improve heart failure mortality ...
3 hours ago | not rated yet | 4
Heart failure accelerates the aging process and brings on early andropausal syndrome (AS), according to research presented today at the Heart Failure Congress 2013. AS, also referred to as male 'menopause', was four times ...
3 hours ago | not rated yet | 1
Women at a particular stage in their monthly menstrual cycle may be more vulnerable to some of the psychological side-effects associated with stressful experiences, according to a study from UCL.
21 hours ago | 3.7 / 5 (3) | 3 |
Two mutations central to the development of infantile myofibromatosis (IM)—a disorder characterized by multiple tumors involving the skin, bone, and soft tissue—may provide new therapeutic targets, according to researchers ...
19 hours ago | 3 / 5 (2) | 0 |
(AP)—Department of Justice lawyers have again asked a federal appeals court in New York to delay lifting age restrictions and prescription requirements on an emergency contraceptive popularly known as the morning-after ...
2 hours ago | not rated yet | 0
Mortality and length of stay are highest in heart failure patients admitted in January, on Friday, and overnight, according to research presented today at the Heart Failure Congress 2013. The analysis of nearly 1 million ...
3 hours ago | not rated yet | 0