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Cardiovascular Fitness Part 2: It all comes down to the right level of intensity

older couple joggingLast week, we talked about the importance of cardiovascular health, but how should you go about training your heart to be strong and healthy?

We did warn, after all, about the perils of overly intense physical activity – like snow shoveling or hitting the ice for that weekly hockey game. Instead, we talked about the merits of getting 150 minutes of moderate-to-vigorous exercise each week, as per the national guidelines.

But when it comes to cardio (a.k.a. aerobic exercise), what is moderate? What is vigorous? If you are woefully out of shape, what is the best and, most importantly, safest way to start?

To answer this question, you must first understand what risk factors you face. Are you already at risk of a heart issue, even a heart attack, due to your current situation? It is vitally important to consult with your family doctor and any specialist they may recommend, to answer this question. It will determine what form your cardiovascular fitness activities will have to take – the type of activity, how often, for how long, and at what intensity.

Intensity – when we talk about light, moderate, and vigorous activity, it all comes down to intensity. How hard is the activity working your heart? How fast will your heart beat as a result?

When you engage in any physical activity, your heart responds by beating harder, to pump more blood to those working muscles. This increased blood flow is necessary to supply your muscles with more fuel (oxygen, sugars, amino acids) and to flush away the toxins that build, like lactic acid (which is what contributes to that muscle burn when you are really pushing it).

How hard can your heart beat?

The general rule of thumb is that maximum human heart rate is 220 beats per minute, minus your age. So, the older you get, the lower your maximum heart rate.

Can your heart beat faster than this?

Yes, but there are consequences – potentially fatal ones. Regularly exercising at more than 85 per cent of your max heart rate can dramatically increase you risk of a cardiac event, like a heart attack. Even if you are in good enough shape and don’t have any risk factors for a heart attack, exercising at this level can still wear on your body and make it weaker instead of stronger, due to overtraining.

Overtraining means you have exceeded your body’s capacity to recover. This can lead to persistent muscle soreness, persistent fatigue, an elevated resting heart rate, increased risk of injury, and irritability.

So, what is the ideal target heart rate?

Too often, people who are not in the best shape overdo it when they start exercising with the hope that this will yield the results they want, faster. Instead, they are only increasing their health risks, as well as making it likely that they will burnout and give up.
Instead, the ideal range is to push your heart rate to 50 to 85 per cent of its maximum, relative to your age.

So if the standard max heart rate is 220 beats per minute (bpm), the ideal range for exercise is 110 to 187 bpm. If you are 40, your range is 70 to 147. If you are 50, it decreases to 60 to 137 bpm.

The poorer your cardiovascular health, the less effort it will take to hit (or surpass) your recommended maximum. The better your cardio health, the harder you will have to exercise to hit your max.

Which means, start off easy and work your way up as the strength and resilience of your heart improves. A beginner may want to start at only 50 to 60 per cent of their max – walking may be all it takes to achieve this. Someone in good shape can drive to 70 or 80 per cent of their max and they may have to run to get their heart rate that high.

And for how long? Exercise at this rate for 20-30 minutes at a time (at least three times a week).

Check out BodyBreak’s target heart calculator and chart.

You can’t track what you don’t measure

This of course requires that your track your heart rate while exercising. These days, there are plenty of wearable devices, at varying price points, that can do this for you. Most of those cardio machines at the gym also have a heart rate monitor – though they are not always reliably functional.

And then there is of course the old-fashioned method of checking your pulse and counting the beats against a clock.

However you do it, it’s important to track your heart rate while you exercise to:

a) Ensure you are working hard enough for your heart to benefit.

b) Not pushing yourself too far, too fast, and driving your heart rate too high.

It’s all about finding your personal Goldilocks zone – not too cold, not too hot, but just right. The result will make your heart stronger, healthier, and more resilient, to better handle that Ottawa winter snow shoveling or those rec league hockey games.

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