By Dr. Rahim Habib ND

As the colder months of winter come, there tends to be a rise in heart attacks. There are several reasons for this: effect of cold on the heart, snow shoveling strain on your body, impact of hypothermia, additional impact on the aged and a reduction in vitamin D level.

In this article, I will speak to how to enjoy the colder winter months with attention to keeping your heart safe.

Impact of cold on your heart muscle

When it’s very cold outside it’s natural to tighten up your muscles and start to shiver. This type of response to cold also happens with your heart – it contracts a bit more and beats a bit faster and can even raise your blood pressure. For most people, this is normal and there is no consequence. However, if you are elderly, have some cardiovascular risk factors, or you have an existing heart problem, it may be of more concern. Harvard researchers published a study in the journal Occupational and Environmental Medicine in 2011 concluding that colder weather tends to increase diastolic blood pressure. The study acknowledged that as the body gets cold, the blood vessels in the outer layer of skin contracts to retain heat which increases the central volume of blood which increases the hearts burden and raises the blood pressure.

Important questions: Shovel or call it a ‘snow day;’ Stay inside or go outside?

If you have to drive to work and have a driveway full of snow to shovel, all of a sudden you have a workout ahead of you. Consider the added fact of now being in a rush with the resultant stress and you have a few more risk factors for having a heart attack. Lifting all of that snow and tossing it a few feet away becomes quite a strenuous start to your day.

Perhaps you are not in good shape, but the sheer weight involved in this snow clearing is significant since snow can be very heavy. It’s a judgement call and in some cases it may be best to not go to work that day, or to say you may be delayed. Get additional help from other family members or neighbours to share the workload, or, take breaks so it’s not a long workout but three shorter workouts.

Seniors are more susceptible to the cold itself, so the question then becomes, do you go outside or stay inside? Heart failure and arrhythmias can be aggravated in the cold. Wind can also rob precious body heat. Adjusting your plans or duration of exposure or clothing are some solutions. For instance, wear multiple layers of clothing. Particularly, choose a good wicking first layer such as silk or synthetic fabrics. A good second layer would be wool or fleece; the third layer can be a light down jacket or fleece jacket. The outer layer or ‘shell’ should protect against the wind and moisture, yet be ‘breathable’ with vents to let moisture out. It’s important to avoid cotton as a first layer since it holds on to moisture and doesn’t insulate when wet. If the weather is just too cold, choose to stay indoors, or go to indoor events rather than outdoor events; if you wanted to go for a good walk, choose indoor exercises instead that day.

Vitamin D and your heart

Since it’s a darker time of year and the angle of the sun is much shallower, you do not get as much ultraviolet light exposure (which is needed to make vitamin D in your skin) so your winter level of vitamin D can get quite low. The average late-winter level of vitamin D is actually below the level of normal, especially for seniors. More studies are finding that the heart is affected by vitamin D.

For instance, vitamin D has specific effects on heart cells and vitamin D deficiency is associated with many established cardiovascular risk factors (eg: blood pressure, heart failure, stroke, diabetes). Some researchers feel that part of why there are more heart attacks in the winter is because vitamin D levels are lower in the winter so you lose its heart-protecting properties. It’s a good idea to get a vitamin D blood test and make sure you’re not deficient (your levels must be above 50nmol/l (20ng/l)). Keep in mind that even though you may be taking some vitamin D orally, it may not be absorbing due to gastrointestinal problems, or your body may not be activating it sufficiently, so, again, it’s a good idea to get tested and to adjust your dose accordingly.