My last blog talked about aging and exercise which inspired today’s blog. Yes no matter how old you are as long as you are healthy and cleared by a physician you can exercise, YAY! However I mentioned that your ability level may change and often this has to do with how intensely you can exercise. What was once a moderate activity for you may now be a vigorous activity. These activity categories are determined by your max heart rate something that decreases with age. I will make this more clear later in the blog, just something to keep in mind as you read
So we are all told we need to exercise, we know this! But how much is enough exercise? And what do Physical Activity Guidelines actually mean?
I am going to break down the guidelines one guide at a time! Today I will start with the Aerobic or cardio recommendations as it follows my last blog nicely.
Canada’s physical activity guidelines recommend adults (18 yrs+) engage in 150 minutes/week of moderate to vigorous aerobic activity (cardio) in bouts of 10 minutes or more. This is the MINIMUM amount for OPTIMAL health benefits. The American College of Sport Medicine provides a little more information by breaking down the amount of vigorous and moderate activity:
CARDIO: Healthy adults should accumulate a minimum of:
30-60 min/day (150 min/week) of moderate physical activity OR
20-60 min/day (75 min/week) of vigorous physical activity OR
a combination of both
** Even less than this is still beneficial for someone who is inactive. Any is better than none!
** If you are not currently active or have a health condition, talk to your doctor before starting an exercise program.
Okay now here is the question that really affects whether or not you are meeting these minimum OPTIMAL requirements: how do you know what intensity you are working at? In other words, how do you know when you are doing a moderate activity or an intense/vigorous activity?
The answer is how intensely you are working which is determined by your heart rate (remember that ‘cardio’ means you are working your heart). The harder your heart works the more intense or vigorous the exercise.
The first step is finding out your max heart rate (HRmax). This is the maximal amount your heart can work through exercise stress and is influenced by age (however remaining active lessens this influence). It is not recommended to exercise at your max heart rate as it can be very dangerous. This should only be done under supervision by a medical professional or exercise physiologist. We find this out just to estimate our training zone.
The only way to find out your EXACT Max heart rate is to have a cardiac stress test done. This is normally done by an exercise physiologist and involves being monitored by an ECG while the intensity of exercise is increased on a treadmill. The participant is stopped when the ECG indicates changes in heart rate. Since it is not likely that most of us will be undergoing a stress test, an equation has been developed to ESTIMATE max heart rate based on age.
Now that you have a little background in exercise intensity here are 3 steps to make sure you are training in the proper zone for optimal health and weight loss benefits:
STEP 1: PREDICTED max heart rate 220-age= bpm (beats per minute)
For example I am 27 years old so my HRmax = 220-27= 193 bpm. I don’t ever want to exercise at this level unless undergoing a cardiac stress test with a professional!
(remember this is an estimate the only true way to find your max heart rate would be to visit an exercise physiologist).
STEP 2: find your target training zone or THR (target heart rate)
Intensity= HRmax x % intensity = bpm
Moderate activity means you are working between 55-69% of your MaxHR. Back to my example of myself:
Intense exercise means you are working between 70-85% of your MaxHR
Exercise above 85% is not recommended without a qualified exercise professional!
STEP 3: Learning how to take your heart rate. This can be done by placing 1 or 2 fingers and feeling the pulse on your neck (carotid artery) or on your wrist (radial artery). Simply count the number of beats while watching a clock for 10 seconds then multiply by 6 to give you amount of beats per minute.
Another way to estimate your THR training zone (but is also not as accurate) is the breathing rule: