How Much Cardio Do You *Really* Need?

For anyone who has yet to make cardio exercise part of their regular routine, a new study offers promise that it's never too late to start.

Even "middle-aged couch potatoes," it turns out, can reverse the harmful effects of a lifetime of sitting with aerobic exercise. The study, published in the American Heart Association's journal Circulation, found that adults aged 45 to 64 who exercised four or five times a week for two years improved how their bodies used oxygen and decreased the stiffness in their hearts caused by sedentary aging.

If you're looking to improve your heart health, what's the best exercise for you, and how much do you really need to do?

"There's not one specific exercise that everyone should be doing and everything will be fine," says Michelin Turnau, manager of prevention programs and policy at the Heart and Stroke Foundation. The goal of exercise—if you're trying to boost your heart health—is to get your heart rate up, which helps blood flow, meaning your heart doesn't have to work as hard to pump oxygen-rich blood throughout your body.

Exercising over time can also help enlarge and strengthen the heart, which will help it pump more blood with each contraction. The Heart and Stroke Foundation and American Heart Association both recommend doing at least 150 minutes of moderate-to-vigorous aerobic physical activity per week for adults—the amount needed to have an impact on your heart health.

Only two in 10 Canadians are meeting those guidelines, but there's good news: It's more achievable than you might think. "You can spread those bouts throughout the day, as long as you're using large muscles to move aerobically and getting that heart rate up for a continuous period of 10 minutes," says Turnau. Here are four ways you can start now.

Walk around the neighbourhood

For someone who's just getting going, a brisk walk will be enough to get to that moderate-to-vigorous intensity, says Turnau. "It depends on the individual, because if you train a lot, what you perceive as a very vigorous workout would be different for someone who's just starting out." If a walk doesn't get your heart racing, start graduating to a short, easy jog.

It's important that your activity is moderate-to-vigorous because you want to have a hard enough impact that you sweat a little and breathe harder, says Turnau. "That's where you're going to achieve those health benefits. If it's less intense than that, you’re not necessarily getting that impact on your health. But if you're going too vigorous, you won't be able to sustain that for too long."

Start lifting weights—or help out with chores in the yard

Cardio isn't the only exercise that can boost your heart health. It's beneficial to add muscle and bone strengthening activities at least two times a week, says Turnau. This means working on your strength and power, which can include lifting weights, but even vigorous gardening that involves a lot of digging or shovelling counts.

Just be careful when you're exercising—or shovelling snow—in the winter. According to Turnau, cold weather can constrict your blood vessels, which can put people who have cardiac issues at risk for going into cardiac arrest.

Bottom line, it makes sense to incorporate both strength training and cardio into your routine. "You want to make it convenient so you can fit it into your routine," says Turnau. "For people who don't have a half-hour slot, you could do 10 minutes in the morning, 10 minutes at lunch, and 10 minutes at the end of the day."

Try interval training

The great thing about interval training—alternating between high-intensity and low-intensity exercise—is that you can be in and out of the gym in less than half an hour. Because interval training makes your heart rate go up and down repeatedly, it's an aerobic exercise, says Turnau. "You're warming up, keeping your heart rate up, resting briefly, and trying it to keep up for a continuous period."

Just don't jump into interval training right away. It's an intense form of exercise, especially for people who've been sedentary. You want to get help, from a trainer for example, in making sure you're doing it properly, and slowly build up the intensity. "You can be sweating and breathing harder, but you should still be able to talk," she says. "It shouldn't be so vigorous you can't even carry on a conversation or you can't talk at all."

Do whatever you enjoy most—and bring a friend

Cross-country skiing, swimming and rowing are just some examples of activities that will get your heart racing while minimizing trauma or weight to your joints. Add some low- and high-intensity intervals to these and you'll have the perfect full-body workout. In terms of heart health, there are no significant differences between these activities, but Turnau recommends changing it up to keep it interesting and including friends and family to ensure you have others holding you accountable to hitting your 150 minutes every week.

"People are more likely to do an exercise if they're doing it with friends, a group, or with their partner," she says. "It also shouldn't be just mom and dad doing activities on their own. If you've got children, choose activities you can do as a family, which will help you be a role model for your children, too."

Originally published February 2018; Updated January 2019.