Seasonal Considerations

Winter Challenges

Cold air causes the skin’s blood vessels to tighten and narrow to prevent heat loss. This increases your blood pressure and therefore the work your heart must do.

When we exercise in the cold, we usually breathe through our mouth. The cold air can irritate the air passages, making it harder to breathe. The nerves in the air passages may tighten and cause a reflex spasm or tightening of the coronary vessels. This could make some people more likely to have angina.

Tips for exercising in the cold

Choose Your Timing

Exercise in the middle of the day when it is warmer and try to avoid times when the wind is blowing hard.


Dress in layers. Cover your head and if you can tolerate it, try wearing a loose scarf over your face to warm up the air before it reaches your lungs.

Reduce your Pace

You may need to walk slower when it is colder, the wind is blowing or there is snow on the ground.


Remember some of your medications, such as beta-blockers, can make you less tolerant to the cold. You may find your hands and your feet get cold faster than in the past.

Indoor Options

It is always a good idea to have a place to exercise indoors on days when it is too cold and windy, there is too much snow or it is icy outside.

Snow Shovelling

Snow shovelling is hard work and can be harmful to your heart for a number of reasons. It can place higher demands on your heart and your blood pressure may climb to dangerous heights to maintain blood flow to your heart muscle.

There are many factors to consider when assessing your shovelling workload, such as:

  • the weight of the snow: dry and light versus wet and heavy.
  • the size and weight of the shovel.
  • your pace or speed of shovelling.
  • your technique: are you using your legs and weight to push the snow or are you mostly using your arms?

MET (metabolic equivalent of a task) is a measure of physical exertion. At rest, you exert 1 MET. The effort needed for different levels of shovelling are written below.

Comparable Workloads
Moderate Snow
(5–7 METS)
Heavy Snow
(7–9 METS)
Very Heavy
Snow Shovelling
(10 METS)
Comparable to climbing
stairs at a fairly fast pace
of 4.5–5 mph
Jogging 5 mph Running more than
6 mph
Comparable to digging in
the garden
Sawing wood Carrying loads up stairs


For most heart patients, snow shovelling is not recommended. If possible, arrange for someone else to do the snow removal for you. If you are going to shovel snow, consider the following guidelines to make the activity safer.

  • Warm-up before the activity.
  • Cool-down gradually afterwards.
  • Allow plenty of time to avoid rushing and stress and take breaks as needed.
  • Wait one hour after a meal before snow shovelling.
  • Use a light, smaller shovel.
  • Limit the amount of snow in the shovel.
  • Don’t lift the shovel too high.
  • Use your leg muscles to assist in the activity, do not just use your arms.

Summer Heat

Exercising in the heat can put a lot of stress on your body to maintain core temperature and fluid balance. As you exercise, you generate more heat and your body temperature increases. To compensate, blood flow is directed to the skin and sweat at the skin surface evaporates and cools the body.

In this way, body temperature returns to normal. However, environmental factors such as bright sunlight, high humidity and lack of wind challenge your body’s ability to dissipate heat and maintain a normal body temperature.

You should be aware of the following signs and symptoms your body is having difficulty coping with the heat: chills, nausea, dizziness, weakness, loss of coordination, profuse sweating but cool and clammy skin.

Tips for exercising in warm weather

Stay Hydrated

Simply drinking water when you are thirsty is not enough to offset the fluid lost during exercise. Drink plenty of fluids before, during and after your exercise.

Choose Your Timing

Avoid exercising in the heat of the day. Instead, choose to exercise early in the morning or in the evening during the coolest part of the day.


Clothes should be light coloured, loose and comfortable. There are unique fabrics that offer UV protection and are lightweight and breathable. Some other fabrics are designed to keep you cool and dry; these include Dri-Fit™ and Omni-Dry™. Wear a hat to limit sun exposure.

Wear Sunscreen

Apply sunscreen to prevent sunburn. A sunburn can decrease the body’s ability to cool itself.

Reduce Your Pace

You may need to reduce your pace for the first few weeks when the weather is warm. It generally takes 7-14 days to acclimatize to the heat. There may be times when the heat and humidity are too high to exercise outdoors. Make sure you have an indoor option for exercise at these times. You can even stroll around an air-conditioned mall.


Certain chronic diseases such as high blood pressure, diabetes and heart disease can impair your body’s ability to regulate temperature, thereby increasing your risk of heat injury. Some medications can also impair your body’s ability to regulate body temperature. Examples include beta blockers, diuretics, vasodilators and anti-depressants.

Be sure to ask your physician if any of your medications affect your ability to exercise in the heat. You may need to exercise earlier or later in the day or find an indoor option.

Air Pollution Considerations

People with heart disease are more likely to experience negative health effects from air pollution. Short-term exposure (hours to days) to air pollution can trigger or aggravate symptoms.

The Air Quality Health Index (AQHI) is a colour-coded scale from one to 10+ designed to help you understand what the air quality around you means to your health, and help protect you from the health effects of air pollution.

When the AQHI is elevated, some people with heart, lung or other chronic conditions may have more symptoms than they usually experience when exercising outdoors. To avoid this, consider moving your exercise indoors, or reducing the intensity or duration of your exercise session.

Low Risk 1-3 Enjoy your usual outdoor activities. Ideal air quality for outdoor activities.
Moderate Risk 4-6 Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptoms. No need to modify your usual outdoor activities unless you experience symptoms such as coughing and throat irritation.
High Risk 7-10 Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy. Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.

Very High Risk

Above 10 Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion. Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

You can find out what the AQHI is in your community by: