Artificial Light and the Biological Clock
Many of the things that we do to babies and young children have been called into question in recent years.
The debate about doing an excessive number of fetal ultrasounds and high tone deafness seems to have gone away for now. Though not disappeared: there is a paper in the week’s Proceedings of the National Academy of Sciences that revisits this important issue. Then there was the realization that doctors were not good at recognizing and dealing with pain in very young children.
And now there is another one that has worried me for years: what happens to babies who are exposed to constant high levels of light? Doesn’t it damage the development of normal circadian rhythms?
I have just seen a study that seems to confirm some of those fears.
Investigators from Vanderbilt University in Nashville examined the impact of exposing babt mice to constant light. The main biological clock is in the brain, and is located in a region called the suprachiasmatic nuclei (SCN). It is responsible for orchestrating an orderly internal physiological and behavioral cycle. It influences the activity of virtually all our organs, including the brain, heart, liver and lungs. It egulates the daily activity cycles that we call circadian rhythms.
When the mice are exposed to normal variations in light the cells of the SCN quickly become synchronized, and a normal circadian rhythm is established. Constant exposure to light disrupted the development of the SCN and prevented the animals from developing normal circadian rhythms.
This is far from being an academic exercise: each year around 14 million premature babies are born worldwide, and many are exposed to artificial lighting in hospitals. If their biological clocks are not allowed to develop normally, we would anticipate that they would, in later life, have less psychological resilience, and to be prediposed to sleep and mood disorders.
I could conceive of a way to test that experimentally by looking at records of people wth those problems. Secondly, we need to see if reducing unnecessary light exposure would have a real benefit for babies, and for the children and audlts that they will become. I would be astonished if exposing babies to a natural spectrum of light and a natural light cycle did not have enormous benefits for them as they grow up.
Helping to Prevent Suicide
Unless you work in psychology or psychiatry, you may not know that in the United States, there are considerably more suicides each year than there are murders.
Though there is sometimes little warning that someone might be about to harm themselves, in the majority there have been some warning signs.
The American Association of Suicidology expert consensus panel has just published a mnemonic to help professionals and the general public recognize some of the major risk factors. You can find a brief article with a link here.
Here is the whole mnemonic:
I Ideation
S Substance abuse
P Purposelessness
A Anxiety
T Trapped
H Hopelessness
W Withdrawal
A Anger
R Recklessness
M Mood changes
This is only a first attempt at an evidence-based summary of some of the major risk factors, and the sensitivty and specificity of the list is still quite low. But If awareness of some of these warning signs and risk factors saves even a single life, this post will have been worthwhile.
Technorati tags: Suicide Depression Self-harm
Sleep, Weight, Insulin Resistance and Diabetes
I am often asked why there seem to be such close links between food and mood. Not just comfort eating, or the sudden shock of lots of carbs when we need an energy jolt, but why drugs that alter mood so often alter appetite?
You will probably not know this, gentle reader, but I only learned of it from reading scholarly papers. Apparently many people report that using marijuana makes them very hungry. On the other hand, cocaine and amphetamine affect not just the metabolism, but also appetite. The link has to do with the evolutionary development of feeding behaviors with the motivation to find food and to be satisfied by it.
Another link that has interested me for many years is the connection between metabolism and sleep. We have always presumed that this link has to do with hibernation: even humans have maintained some hibernation responses.
There is extremely good evidence that there is an inverse relationship between the number of hours that you sleep and an increase in your weight. There have been a great many studies on this, but one of the best was published by a group of researchers from the Mood and Anxiety Disorders Program, at the National Institute of Mental Health, the Psychiatric University Hospital, Zurich, Switzerland; University of Pittsburgh School of Medicine and the Department of Psychosocial Medicine, Zürich University Hospital, Switzerland in the Journal Sleep in 2004.
A report from the BBC concerning a study presented to the American Thoracic Society International Conference in San Diego provides yet more evidence of this link between sleep and weight. Researchers from Case Western Reserve University in Ohio, followed nearly 70,000 women for 16 years. They found that women who slept five or fewer hours a night were a third more likely to put on at least 33lbs (15kg) than sound sleepers during that time. It also found that compared with women who slept for seven hours a night. lighter sleepers were 15% more likely to become obese (have a Body Mass Index (BMI) of 30 or more. {BMI is calculated by dividing your weight in kilograms by the square of your height in meters}).
Previous studies, some of which I have reported before, have shown that after just a few days of sleep restriction, the hormones that control appetite cause people to become hungrier. However the women in the study appeared to eat less. I say “appeared to,” since the use of personal evaluations of food intake are notoriously inaccurate.
In dozens of countries arond the world, I am regarded as an authority in the fields of endocrinology, metabolism and nutrition. But when a group of us tried to estimate our daily intake and compare it with meticulous diaries, we discovered that we – a group of internationally renowned experts – were off by around 500 calories per day.
All kinds of explanations have been advanced, from people who didn’t sleep getting up and binge eating; to the effects of sleep-deprived people craving high carbohydrate, high fat food; to insomnia being a result of anxiety or depression that releases hormones that cause us to lay down fat in our tummies.
For all kinds of complex biochemical reasons, I have always felt that a lack of sleep would lead to an increase in insulin resistance, that may cause an increase in the deposition of fat in key regions of the body.
Some new research suggests that I may have been right on this one. A group based at Yale University School of Medicine, in New Haven, Connecticut has just published a report that should be of interest to all of us, and in particular you multi-tasking insomniacs out there.
The investigators studied a cohort of men from the Massachusetts Male Aging Study who did not have diabetes at baseline (1987–1989) and who were followed until 2004 to look for the development of diabetes mellitus. They came to the conclusion that BOTH very short and extra long sleep durations increase the risk of developing diabetes, independent of confounding factors.
The take home message?
If you do not get 7-8 hours sleep each night, you are vulnerable to a great many problems, and perhaps the biggest of all is the risk of weight gain, insulin resistance and diabetes mellitus.
I do not recommend using sleeping tablets unless absolutely necessary, and then for just a few days at a time. Instead follow all the sleep strategies that I have talked about in earlier blog entries.
During a recent visit to Danville, Virginia, I was delighted to learn that one of the non-pharmacological approaches that I have found helpful – putting a cold compress on the abdomen – was used by General Stonewall Jackson who used this very technique that I had to learn by going all the way to China.
The bottom line? Before your sleep gets disrupted by being overweight and you develop sleep apnea, try some simple sleep hygiene, and a few of these novel techniques.
Technorati tags: Insulin Insulin resistance Insulin resistance syndrome insomnia alternative medicine resilience
Sleep and Mood
The interaction between sleep and mood is fascinating, complex and supremely practical.
I have received a couple of queries and comments. Let me start with one from a physician:
“I have a question about sleep disorders. My patients seem to suffer from this even after their depression is better.”
This is an extremely interesting issue.
Every healthcare student has been taught about the sleep disturbances that may occur in association with mood disorders. The classic problems in depression are early morning wakening, difficulty in getting off to sleep and sometimes waking in the early hours. Some others will sleep for very long periods, and there has been speculation that this may be a form of hibernation behavior. People with abnormally elevated mood can often stay awake for days at a time. There is also the well-known problem of seasonal affective disorder, in which the long winter nights can cause depression. Fortunately the depression is often relieved by the use of a light box.
Many experts now consider that the disturbances of sleep are often the primary problem, which then cause depressed or elevated mood. This is actually not a new idea: one of the old fashioned treatments for depression was sleep deprivation and many of us who have worked all night have experienced the mildly manic symptoms of sleep deprivation. On early morning rounds at the hospital I commented that it was easy to tell if some of the residents had been working all night, even before they presented their reports. The giggling, high energy and disturbances in thought patterns were not at all what one sees when someone is tired.
It is not just the sleep deprivation, but also light. It is well known that people suffering with bipolar disorder are more likely to get manic episode in the spring and early summer, as the amount of ambient light increases. It is the converse of the seasonal affective disorder problem.
So what often happens is that antidepressant medications do indeed help with the depressed mood, but the underlying sleep problem takes much longer to correct itself. This is also one of the reasons why people who have seen their mood improve on treatment still have cognitive problems that can go on for months after the mood symptoms have been corrected. It is probably a combination of sleep deprivation and also the impact of corticosteroids that can rise in some sufferers causing transient damage to some key regions of the brain.
It would be nice if we could modulate people’s sleep/wake cycles and thereby treat the mood problems directly, but at the moment, despite the enormous advances in pharmacological treatments of sleep problems, we are still not able to do that reliably.
Technorati tags: Sleep, Mood, bipolar disorder, Depression,
Mr. Black
I have previously talked about working with animals for therapy. There is ever increasing evidence that animals experience emotion: no surprise at all to anyone who has ever spent any time with one.
Someone heard that I was in the market for a new horse, and since I’m six foot four, he or she needed to be big. So I was asked if I would be interested in meeting a horse called Blackie. At the time he was 22 years old, and until six months earlier had enjoyed a happy life, which had included being a calendar horse – he was once Mr. September in the Quarter Horse calendar! – a part in a movie, and competitions all over the country. Then tragedy had struck. His owner died under tragic circumstances and the horse was left in a field and forgotten. Soon the daughters of the owner came on the scene are were keen to find a good home for the horse. When I was asked if I would like to see him, my first question, was “Has anybody explained to the horse what happened to his human friend?”
So he was brought over for me to have a look at. What a sorry sight. He was quite obviously clinically depressed. He would not lift his head, his ears drooped, he walked as if he no longer had any will to move, his eyes were anguished and physically he was a mess. More than one hundred pounds overweight, his hoofs looked like old cracked ivory and he was covered in nasty looking skin lesions. So I climbed on him and took him out to a quiet place where I could talk to him. Once out of sight, I dismounted and started chatting with him. I told him what had happened to his last owner, who I was, and asked him if he would like to come and live with me for a while.
After a few minutes he lifted his head and started nuzzling me, which I took as a “Yes.” When we rode back together an hour later everyone asked what had happened? For now he had a spring in his step, his head was up, his ears forward and his eyes looked bright and shiny. Even his coat looked better. Over the next few weeks everyone at the stables talked to him, we gave him a new name, enthusiastic volunteers exercised him every day, he received Reiki, acupuncture and massages, and his skin lesions were treated with a homeopathic remedy called Thuja. He became everyone’s favorite horse and the new chief of the herd.
Now several years later he continues to get regular TLC and has the energy of a much younger horse. And now he is returning the favor. He has agreed to help provide therapy for the handicapped. “Agreed?” you may ask. Why yes: I wouldn’t dream of having him do anything without first asking him.
Equine assisted therapy is becoming popular and there is some good scientific research indicating its effectiveness. In the United States, the non-profit North American Riding for the Handicapped Association is a central coordinator of these programs, and their website contains a great deal of interesting and useful information. On January 29th, they will be launching a partnership with Animal Planet to produce two horse-themed programs.
Technorati tags: animal therapy, horse,
