Tis the Season?
“This is the winter of our discontent” writes Shakespeare. More than discontent – actual demise. New data analysis performed at UCLA looked from sea to shining sea – 1.7 million death certificates across the U.S. The figures demonstrated that no matter whether you live in cold or warm climates, American cardiovascular deaths increase by a third during winter.
Winter is deadly.
Warmer weather does not wither winter’s wrath – at least if you look at measures of the heart disease and survival. There are truly different seasons for the heart.
Should We Be Surprised by This Data?
Not really. The surprise is that people – and researchers – are surprised. Seasonal changes affect many illnesses, whether it’s the incidence of schizophrenia or the nature of influenza deaths. Just as body clocks change death rates over the 24 hour cycle, with the peak of cardiovascular deaths generally between 9 and 11 AM, there are massive internal changes over weeks, months, and seasons.
An example – the peak time of death in the US is Monday morning. People “blow out” their 24 hour clocks with later evenings and waking times throughout the weekend. Another example is the menstrual cycle, which has just been implicated in changing rates of asthma – and provoking coughing in women who do not have asthma.
Time rules life. Internal clocks change how we respond to pretty much anything that happens to us.
So consider – why wouldn’t seasons change disease incidence? The opposite presumption is the impossible – that the body is a machine that preserves functions exactly the same forever - no matter what. We change all the time – consider your overall alertness at 4 P.M. versus 4 A.M. We also change throughout the seasons.
And the environment around us changes, too – along with all the living things in it.
Why Did the Researchers Believe Heart Attacks Went Up in Winter?
They considered at least two possibilities – both relationships to other illnesses that are known to change seasonally. One is depression. Depression is far more common in the winter, when up to half of the people in the Northeast experience at least some diminution in mood – a major factor in the population growth of the sunbelt.
Next up was influenza, which also peaks in the winter.
Why Would Depression Increase Cardiovascular Deaths?
There are many known reasons. Depression represents an inability of the body to respond and adapt. Whether “caused” by pancreatitis, hypothyroidism, death of a loved one or innumerable other factors, depressed people show blunted adjustments to most stresses in life.
They experience more brain cell death. They pay less attention to food and grooming. Exercise levels decrease. The researchers noted that depressed folks might take medications less appropriately – an answer in keeping with the present medical model of body as machine.
Yet depression changes many “normal” human responses – up to and including personality. Many of the witches burned at the stake in the 17th century were probably depressed or suffering from manic-depression. They were “possessed by the devil” – what else could explain their extraordinary changes in personality and behavior?
One hopes our explanations of why people die frequently in winter have hopefully changed since then.
Why Does Depression Increase in Winter?
There are numberless factors like economic and social changes – not to mention the holidays. But one major factor is light. With less sunlight, people become more depressed.
Does Light Affect More than Mood?
Absolutely. Light is a major drug.
Light resets most internal clocks – the timers that act as controllers on everything we do. Light activates natural killer cells. Light changes alertness. Light on the skin creates vitamin D.
Change the level of light and you change people, their feelings, performance, and mood.
What Else Changes Powerfully with Seasons?
The environment. As a superorganism with 100 trillion bacteria living in our guts – not to mention those living in the lungs, sinuses, genitalia and skin, nor the fungi, prions, rickettsia, mycoplasma, viruses and others hanging around, we are highly suspectible to what happens to the many other organisms we live with. And that’s all before we look at the changes in our diet brought on by winter.
Time rules life. Many diseases change over the 24 hour day, the menstrual and monthly cycles, and the seasons.
Our daily and weekly changes in mortality only highlight the fact that humans continuously change from moment to moment. Recall a memory and it changes; move in and out of light and mood and alertness change. As we rapidly use up the chemicals of life – our sugars, proteins, and fats – we remake ourselves constantly.
And seasons change those changes. Perhaps as we understand them better, we will treat the increased cardiovascular risks of winter by reading and eating next to artificial light, or through engaging longer periods walking (bundled up) under the winter sun. Then the discontent of the year’s last season may shift to another experience Shakespeare described well – life “as sweet as summer.”