The Beat is taking a short break for the summer. Before we go, we’re sharing some heart-healthy advice for you to have (safe) fun in the sun this August. That is to say, before you grab your sun glasses and beach towel, you’ll want to read this first.
The Heart and the Heat
Hot, humid weather can place significant stress on the cardiovascular system. Bright sunlight, high humidity and lack of wind and shade challenge the body’s ability to dissipate heat and maintain a normal body temperature. The mechanics of it are simple: under extreme temperatures, the heart has to beat faster than usual to pump blood to the surface of the skin to assist with sweating to cool the body. This causes strain on the heart. Too much of it – and not enough cooling – can cause damage to vital organs, leading to a potentially fatal condition known as a heat stroke.
Heat stroke can happen to anyone, but those with cardiovascular disease are at greater risk, explains Dr. Jennifer Reed, a scientist in the Division of Cardiac Prevention and Rehabilitation at the University of Ottawa Heart Institute.
“Patients with heart disease including heart failure and hypertension are at increased risk of heat-related illnesses, especially during exercise or vigorous levels of physical activity,” says Dr. Reed.
As well, Reed warns that patients who are prescribed medications to manage their disease may be at elevated risk. “Medications such as beta-blockers which lower heart rates may limit the amount of blood that is redistributed to the extremities and skin for cooling. Research has also shown that blood vessel dilation is impaired in patients with heart failure.”
Patients are advised to talk to their doctor about how their medication may affect their heart in extreme heat.
The University of Ottawa Heart Institute encourages everyone to follow these important tips below to keep cool this summer.
How to avoid heat related injuries:
- Drink plenty of water to keep your body hydrated.
Dr. Reed says drinking water before, during and following exercise in the heat is important to maintain good hydration. She recommends drinking approximately 3 to 8 oz of water (a 'gulp' of fluid is about 1-2 oz) every 15- to 20-minutes during exercise.
- Avoid vigorous, high-intensity activity in extreme heat conditions.
Dr. Reed says exercising in an air-conditioned or well-ventilated facility or in a cooler, shaded area is best for hot days. “Or, better yet,” she said, “find a pool or beach to keep cool, swim laps and have fun!”
- Wear comfortable, light coloured, loose fitting clothing to help you stay cool in the sun.
Dr. Reed says wearing shorts and a t-shirt exposes the skin and encourages heat loss from sweat. She recommends wearing materials such as cotton that "wick" sweat to the surface to help with heat loss.
- Wear sunscreen and a hat.
Dr. Reed says sun burns make it more challenging for the body to cool itself. It is best to apply sun screen up to 40-minutes before sun exposure to get the best results.
- Be aware of the symptoms of heat injury.
Chills, nausea, dizziness, weakness, fainting, and profuse sweating are all warning signs of heat exhaustion and heat stroke. If you experience any of these symptoms, find a cool shaded area, relax and drink plenty of water and, if you’re feeling unwell, consider returning home to rest.
- Don’t be shy to ask for help.
If you need a fan, to borrow some sunscreen, a cool place to stay – or anything else to help beat the heat, ask a friend or family member for help.
For more information about how you and your family and friends can maintain a heart-healthy lifestyle this summer, consult the University of Ottawa Heart Institute’s Prevention and Wellness website.
