Could Winter Weather Increase Your Heart Attack Risk? Research Says… Maybe So
From childhood on, we hear people who are convinced that health problems are connected to weather conditions.
“Don’t get out in the cold with a wet head or you’ll catch a cold”
“Rain must be coming in, my arthritis is acting up.”
“The temperatures going up and down so much it’s making everyone sick.”
Often dismissed as old wives’ tales and anecdotes, science has shown there is indeed a connection between the weather and people’s health. While the most common potential issues are arthritis pain, a bad cold or the flu, the weather may impact conditions much more serious. Weather could impact heart health.
Even in the 1920’s researchers had begun to note an association between cold weather and heart attack. Over the years, multiple studies have examined this link to determine how and why the two occur together. Among the theories proposed is that the colder the weather is, the higher the risk of heart attack.
Supporting this theory, a 2004 Continuing Education in Anaesthesia, Critical Care & Pain text titled, “Acute coronary syndromes”, noted the association between cold weather and angina. It stated:
“although in most cases angina occurs in association with increased heart work during physical exercise, it can also occur as a result of autonomic changes. For example, angina is classically worse in cold weather because changing autonomic tone causes coronary artery constriction.”
A brand-new study, the largest to date, was published in JAMA Cardiology in October, 2018. Researchers gathered weather data from the Swedish Meteorological and Hydrological Institute for 1998-2013. Researchers then retrieved records for all myocardial infarctions (MIs) that were reported to the Swedish nationwide coronary care unit registry, Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART) from the same 15-year time period. Of the initial 280,873 patients, they were able to match up weather data for 274,029 (97.6%) of them.
Because they had access to more than simple temperature highs and lows, (including: daily mean air temperature, minimum air temperature, maximum air temperature, wind velocity, sunshine duration, atmospheric air pressure, air humidity, snow precipitation, rain precipitation, change in air temperature and air pollution.) they could research multiple weather factors.
Lead author Dr. David Erlinge, the head of cardiology at Lund University in Sweden noted: “People have been talking about weather and heart attacks for about 100 years… With our robust data, we can separate out many more factors than just the cold.” The researchers spent over a year (February 2017 through April 2018) studying and analyzing the data in an effort to answer the question:
“Is the incidence of myocardial infarction affected by different weather conditions?”
When all the data was tallied, they found that rate of MI increased with:
- lower air temperature
- lower atmospheric air pressure
- higher wind velocity
- shorter sunshine duration
A mere 13 degree (7.4 degree C) increase in air temperature corresponded with a 2.8% reduction in risk of MI! Results were consistent for a large range of sub-groups and health care regions within the country. Air pollution did not change their results.
Erlinge offers varied explanations for this including the contraction of blood vessels in the skin to conserve energy and temperature, which increases the workload of the heart and thereby the risk of a heart attack. Inclement, cold weather may also increase emotional stress, which is tied to the incidence of heart attack.
There is also speculation that behavioral changes such as diet or exercise habits, less exposure to sunlight or the increase of respiratory infections during the cold months may be impacting the rate of MI.
Oddly, however, researchers noted that the correlation between cold temperatures and heart attack was actually absent for those in the northern parts of the country where it is the coldest. This led researchers to the theory that it may be the “extreme fluctuation in temperature that affects heart health” more than just the extreme temperature.
Going forward, more studies may explore the correlation between weather and heart health in regions of the United States where fluctuations are more common as well as if staying indoors or wearing warmer clothes is sufficient to reduce MI risk. Additionally, since most of the subjects in this study were around 72 years old, including younger individuals may also be of benefit. Most MIs occur in older people, but it could be that even younger hearts are affected by weather in a less severe way.
These and many other questions remain for future studies to answer. In the meantime, “Many older people move to warm, sunny places in retirement,” Erlinge said. “Our study indicates that that is a good idea.”
If you have questions regarding your heart health risk factors or looking to establish a routine that promotes heart health, talk to your chiropractor at your next visit. Chiropractors can help you stay active and pain-free, as well as assist you in evaluating steps you may need to take in order to reduce your risk for heart disease.
They can also refer you to another health care provider for additional evaluation and treatment, as needed. You can find a TCA member doctor near your home, work or school at https://www.tnchiro.com/find-a-doctor/.
REFERENCES:
Bharanidharan, S. “How Does Cold Weather Affect Your Heart Attack Risk?” 10/26/2018. https://www.msn.com/en-us/health/healthy-heart/how-does-cold-weather-affect-your-heart-attack-risk/ar-BBOUT8k?ocid=spartanntp
Channer, KS MD FRCP, Sheppard, LP BSc FRCA. “Acute Coronary Syndromes”. Continuing Education in Anaesthesia, Critical Care & Pain. Volume 4, Number 6, 2004.
Liverpool, L. “Cold, cloudy weather ‘could increase your risk of having heart attack’” Oct 24 2018. https://www.theguardian.com/society/2018/oct/24/cold-cloudy-weather-could-increase-your-risk-of-having-heart-attack
Mohammad MA, Koul S, Rylance R, et al. Association of Weather with Day-to-Day Incidence of Myocardial Infarction, A SWEDEHEART Nationwide Observational Study. JAMA Cardiol. Published online October 24, 2018. doi:10.1001/jamacardio.2018.3466