Blood pressure harder to control in winter

The first thing I thought was vitamin D, but it wasn't mentioned.

http://news.yahoo.co..._lwiEejTdas0NUE

ORLANDO, Florida (Reuters) - For people with high blood pressure, the condition can prove tougher to control in the winter, researchers said on Monday.
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Veterans treated in the winter were less likely to see their blood pressure levels come down to a healthy level than those treated in the summer, researchers told an American Heart Association meeting.

The five-year study focused on blood pressure readings for 443,632 U.S. military veterans with hypertension, or high blood pressure, in 15 cities, including such far-flung locales as chilly Anchorage, Alaska, and warm San Juan, Puerto Rico.

In each place, the researchers found, fewer of the veterans -- regardless or race or sex -- returned to normal blood pressure levels while treated in winter months compared to the summer.

"We are seeing seasonal variation in all of the cities," Department of Veterans Affairs researcher Dr. Ross Fletcher, chief of staff at the VA Medical Center in Washington who led the study, said in an interview.

High blood pressure typically has no symptoms, but it can lead to major health problems including stroke, heart failure, heart attack and kidney failure. It can be controlled with lifestyle changes and medications.

Eight percent fewer patients returned to a normal pressure reading during treatment in the winter compared to the summer, according to Fletcher.

About 60 percent of the patients had a marked change in blood pressure control in the winter, Fletcher added.

Fletcher said the researchers have not figured out just what is causing this, but it did not seem to be changes in temperature or daylight that occur in the winter or the latitude of the city.

Instead, Fletcher said, the trend may be driven by weight gain, different eating habits and less exercise during winter. He said the data showed the veterans did, in fact, gain weight during winter. Weight gain can contribute to hypertension.

"I don't think it's the blood pressure rise that creates the weight gain. I think it's the weight gain that might create the blood pressure rise," Fletcher said.

Fletcher said people might eat foods with more salt in the winter as well, which also could help drive up blood pressure.

"There have been data looking at seasonal variation in heart attacks and strokes. And they tend to be higher also in the winter," added Dr. Robert Bonow of Northwestern University Feinberg School of Medicine, a spokesman for the American Heart Association.

People should be aware of the possibility their blood pressure may be harder to control in the winter and should be more vigilant during this time, Fletcher said.

"It does appear that if one wants to have very tight control of blood pressure, that the 'winter dip' in control should be addressed -- if not by a change of lifestyle, perhaps even by a change of medication," Fletcher said.

The first thing I thought was vitamin D, but it wasn't mentioned.

That was my first thought too. Hard to believe it is not involved. I wonder if they looked at the geographical distribution of their patients? (i.e. North-South distribution)

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At first it was assumed that in places like the Mediterranean, better blood pressure was attributed to their diet. But this always sounded dodgy as non-Mediterranean diets can be just as varied and healthy, and as exotic, so vitamin D could be the rational clincher.
I don't know much about BP and D personally yet, but high blood pressure all year round could just be down to D deficiency (at least in a good wad of cases if not all). Even if you have a good Summer you still need to get out there and enjoy it. Not many people do, which is why it's so common.

Just like plants need water, nutrients from the soil and the sun to survive, so do we and other animals. I sincerely hope D information gets aggressively promoted.

Vitamin D is not clearly implicated, there is a pretty big boat load of evidence that shows that visible bright light alone improves mood without the UV-B wavelengths needed to increase Vit-D production.
http://www.sciencene...050423/fob7.asp

A research review commissioned by the American Psychiatric Association in Washington, D.C., concludes that in trials, daily exposure to bright light is about as effective as antidepressant drugs in quelling seasonal affective disorder (SAD), or winter depression, and other forms of depression.

It seems to me more likely that Vitamin D is not implicated, but it may be as the following review indicates. I take Vitamin D @ 3000ui for other health reasons, so I'm not really invested in whether it helps with depression or not.

Here is a good review, I haven't read all of it:
http://www.vitamindc...epression.shtml
An excerpt:

Vitamin D and Depression

Is psychiatry that branch of medicine that can explain everything but predict nothing? No group of scientists is working harder to change that definition than those at the National Institute of Mental Health (NIMH).

Among the scientists at NIMH are many of the most famous names in psychiatry and some of my personal heroes. They know that nothing could be a crueler message than to tell those suffering from major depression that physiological amounts of vitamin D will cure it. Premature claims for a variety of nonprescription supplements have given suffering millions hopes that were soon dashed on the rocks of scientific reality. Even the supplements that may help such as SAMe, omega‑3/omega‑6 intake ratios, or lowering homocysteine with adequate methylating B vitamins/TMG are not cure‑alls.

Perhaps raising false hopes of curing an illness as devastating as major depression is not as serious as some of psychiatry's past crimes, such as telling mothers of schizophrenics that they caused their child's illness or using false recovered memories of sexual abuse to the destroy innocent families. That said, we must not raise false hopes. Nevertheless, what do we know about major depression and vitamin D?

Seasonal Affective Disorder

Harris and Dawson‑Hughes found 400 IU of ergocalciferol (vitamin D2) did not help the seasonal mood swings of 125 Boston women compared to placebo. Harris S, Dawson‑Hughes BSeasonal mood changes in 250 normal women.Psychiatry Res. 1993 Oct;49(1):77–87. Such mood swings can be severe and are related to season, latitude and sun exposure. The authors did not obtain 25(OH)D levels but we now know 400 IU of ergocalciferol is close to a homeopathic dose of vitamin D. We also know ergocalciferol is a significantly less potent form of vitamin D than is the naturally occurring vitamin D3, cholecalciferol. One of the authors, Professor Dawson‑Hughes, will be the first one to tell you 400 IU of ergocalciferol is an inadequate dose of vitamin D.

If you are thinking that Oren, Schulkin and Rosenthal have already shown that vitamin D has nothing to do with seasonal affective disorder, I am sorry to tell you they measured the wrong vitamin D metabolite, 1,25(OH)2D3 (calcitriol), which can be high, low, or normal in almost any condition. Oren DA, Schulkin J, Rosenthal NE1,25(OH)2 vitamin D3 levels in seasonal affective disorder: effects of light.Psychopharmacology (Berl). 1994 Dec;116(4):515‑6. The only lab test that should be used to measure vitamin D stores, vitamin D deficiency and vitamin D adequacy is 25(OH)D, which they did not measure.

In a 1998 controlled experiment, Australian researchers found that cholecalciferol (400 and 800 IU), significantly enhanced positive affect when given to healthy individuals. Forty‑four subjects were given 400 IU cholecalciferol, 800 IU cholecalciferol, or placebo for 5 days during late winter in a random double‑blind study. Results on a self‑report measure showed that vitamin D3 enhanced positive affect a full standard deviation and there was some evidence of a reduction in negative affect. The authors concluded: "vitamin D3 deficiency provides a compelling and parsimonious explanation for seasonal variations in mood." Lansdowne AT, Provost SCVitamin D3 enhances mood in healthy subjects during winter.Psychopharmacology (Berl). 1998 Feb;135(4):319‑23.

In 1999, in an even more interesting study, the vitamin D scientist, Bruce Hollis, teamed up with Michael Gloth and Wasif Alam to find that 100,000 IU of vitamin D given as a one time oral dose improved depression scales better than light therapy in a small group of patients with seasonal affective disorder. Gloth FM 3rd, Alam W, Hollis BVitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder.J Nutr Health Aging. 1999;3(1):5–7. All subjects in the vitamin D group improved in all measures and, more importantly, improvement in 25(OH)D levels levels was significantly associated with the degree of improvement.

German authors found healthy controls had an average serum 25(OH)D of 46 ng/L while depressed subjects had 37 ng/L. Schneider B, Weber B, Frensch A, Stein J, Fritz JVitamin D in schizophrenia, major depression and alcoholism.J Neural Transm. 2000;107(7):839–42.Finnish authors found no seasonal differences between seasonal affective disorder patients and normal controls but also found no seasonal variations in 25(OH)D levels in the same patients. Partonen T, Vakkuri O, Lamberg‑Allardt C, Lonnqvist JEffects of bright light on sleepiness, melatonin, and 25‑hydroxyvitamin D(3) in winter seasonal affective disorder.Biol Psychiatry. 1996 May 15;39(10):865–72.Most recently, a direct correlation was found between 25(OH)D levels and mental health scores in a group of healthy, elderly adults—although 1,000 IU of cholecalciferol did not improve mental health scores of these highly‑functional subjects.

I don't have the research on me right now (published within the last year or so), but someone explained the reason as being related to temperature. This particular study looked at people who had heart attacks while shoveling snow, a very common occurrence among people over 50 or out-of-shape. They came to the conclusion that the rapid constriction of blood vessels in cold weather (a natural evolved defense to keep your core body temperature warm, the reason why your fingers and feet are the first to get cold) caused a substantial rise in blood pressure which led to frequent heart attacks. To me it makes sense from a physical standpoint. Your circulatory system has a defined volume, if that volume shrinks 5 or 10% over the course of a few minutes (in the cold), then your blood pressure is going to rise.

Perhaps they should make sure people who they are testing for blood pressure in the winter have not just recently come in from the cold (or at least an environment that is colder than the examination room).

My earlier post may be a little confusing where as I started talking immediately about mood and depression. I figured that poor mood / depression was putative mechanism effecting diet, exercise, weight gain, and ultimately blood pressure. And since vitamin D has been implicated to improve mood (but not proven by any means), I went on to talk about that.

There are some other clear studies showing that stress via depression or anxiety increases blood pressure. Perhaps it is the lack of bright visible light (non-UVB) that is causing the negative change in mood which is causing both the weight gain and the increase in blood pressure.

That sounds like an interesting study mind, sounds believable to me.

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There's no doubt that a bright sunny day (not the lights you turn on in the evening), even from within doors, makes you feel good and that contributes to a positive state that impacts on the body.

People with chronic fatigue syndrome are noted to have low body temp. and D causes an increase. So, I think there's the benefits of seeing and feeling the sun as well as D production.