Saturday is Cardio Day

I said that Saturday is Cardio Day, but the title is misleading. I try to get a short cardio workout in every time I’m at the gym, which in my case is Monday through Friday. My doctor said he’d like to see me do cardio at least two hours a week. On a perfect week, if I do cardio 25 minutes a day five days a week, that’s 125 minutes or just slightly over two hours.

I don’t always have perfect weeks. This week isn’t perfect.

So I usually go to the gym Saturday morning when it opens at eight to do some more core work and get an additional cardio in. Since I’m not limited to an hour as I am during the work week, I can take a long time on the elliptical machine and get in a good heart-pounding workout.

A few Saturdays ago, after doing a little core work, I decided to trade duration for intensity and did a full hour of cardio. I felt pretty good when I left the gym and was proud of my ability to do a complete hour. The following Saturday, since I had missed my Friday Biceps/Triceps workout, I did that exercise routine first, moved to core work, and then I decided to do another full hour of cardio.

That was a mistake.

I made it to 55 minutes. I realized somewhere halfway through my cardio exercise that I was becoming more fatigued than I expected so I cut things a little short. The weight training workout took a lot more out of me than I thought. In fact, after leaving the gym and going home, it took hours for my heart rate to get back down to a resting level, which for me is around 60 to 64 beats a minute.

The moral of the story is not to push it. Here are some reasons why too much cardio may not be healthy.

I just read an article at the fitness blog for the New York Times called Slow Runners Come Out Ahead. Here’s a relevant excerpt:

The ideal amount of jogging for prolonged life, this nuanced analysis showed, was between 1 hour and 2.4 hours each week. And the ideal pace was slow.

This information is drawn from a number of studies including a 2012 study of cyclists in Denmark and a study just recently published in the Journal of the American College of Cardiology.

However, the research didn’t specify the exact level of intensity or pace they consider “slow,” so it’s possible that optimal pacing may vary from person to person depending on their general health and other factors.

(It should be noted that while the L.A. Times also picked up and endorsed these studies, a Forbes magazine piece pointed out some serious flaws in the “less is more” thinking about aerobic exercise. On the other hand, there are those who think science tells us that cardio kills. It’s tough to figure out whose research should be considered the authority, especially when your long-term health hangs in the balance.)

But assuming for the moment the articles at the New York Times and L.A. Times are valid, it all this seems to go along with what my doctor’s been saying to me. As I mentioned, he told me that 120 minutes of cardio per week is the minimum requirement for people my age, and he also told me he wants me to back off the intensity. All that said, I don’t feel like I’m working out if my pace is equal to a causal stroll through the park. I want to work stronger and push my limits, but how much is too much?

According to popular wisdom, a person should shoot for a heart rate of between 60% to 80% of their maximum to be in the aerobic range. There are all kinds of calculators available on the web including this one to help you figure out what 60 to 80 percent means for you.

I plugged in my age and 60% of maximum and got a target heart rate of 96 beats per minute and a recommended target range of 88 to 136 beats per minute. I did it again selecting 80% of maximum and the target changed to 128 beats per minute with the recommended range remaining static.

older runners
Photo credit: Steve Earley – The Virginian-Pilot

In other words, the calculator is telling me that I should never exceed 136 beats a minute. But in my current cardio sessions, I regularly operate somewhere in the 149 to 159 beats per minute range.

I decided to set the calculator for 100% of maximum heart rate just for giggles and it came back with 160 beats a minute. In my most intense cardio sprints, I can get my heart rate up to around 160 to 162.

I guess that’s overdoing it.

Here’s another way of calculating a training range, in this case, of 70% of maximum:

  1. 220-age = Max HR.
  2. Subtract resting heart rate from Max HR = Heart Rate Reserve (HRR).
  3. Multiply HRR times percent you want to train at.
  4. Add back resting heart rate.

I’m 60 years old, and assuming a resting heart rate of 65 beats per minute and 70% training range, the calculation is 220 – 60 = 160, 160 – 65 = 95, 95 x .70% = 66.5, 66.5 + 65 = 131.5.

So around 131-132 beats per minute should be my heart rate at 70% of maximum.

An article at said that recent research suggests a new way to make this calculation:

  1. Multiply 0.7 times your age
  2. Subtract that number from 208

So for a 60-year-old, the calculation is 0.7 x 60 = 42, then 208 – 42 = 166. I then have to take the value 166 is plug it in to step one of the formula above, substituting it for the value 220.

The result for me is 93.7 beats per minute is my target heart rate for 70% of my maximum. This is assuming that I’m following the formula correctly.

According to all of this information, I’m still overdoing it by quite a bit. My doctor said to shoot for somewhere in the 140s which is still a bit high by these standards.

But I feel fine after my cardio workouts. Not sure if this means I’m damaging my health but I have to consider other factors such as my having worked up to a higher level of endurance than a more sedentary person or someone who is active but to a lesser degree.

While these calculations take age into consideration, they don’t take other factors such as athletic ability, gender, or other concerns, so I have to assume the results are rather generic. It would probably take a detailed medical examination and consultation to accurately define what the target percentage of any given individual’s maximum heart rate would be. On the other hand, it’s probably better to start out underestimating your aerobic ability than to overestimate it.

I said yesterday that I was going to define and discuss both aerobic and anaerobic exercise, so let’s go through a brief summary.

According to Wikipedia, Aerobic exercise is characterized by light-to-moderate intensity activities that utilize oxygen to adequately provide for the energy demands being generated during a medium-to-long distance/duration exercise. These are activities such as running, jogging, swimming, cycling, and walking.

In other words duration is emphasized over intensity of muscular contractions.

older weight lifter
Joe performing preacher curls with dumbbells

Anaerobic exercise, by contrast, is characterized by short, intense bursts of activity which trigger lactate formation (“the burn”). These are activities such as weightlifting, weight training, short-distance intensive runs such as sprints, and so on.

In other words short-term intense muscle contractions are emphasized over long distance/duration exercise.

As it turns out, both are good for you, which is why I have a combined routine when I go to the gym.

According to the blog at Fitness 19, the benefits of aerobic exercise are as follows:

It is difficult to overstate the benefits of aerobic exercise. It not only improves overall health and quality of life, but may also extend your life. Aerobic exercise burns fat, improves mood, strengthens the heart and lungs and reduces your risk of diabetes.

While the benefits of anaerobic exercise:

…helps build lean muscle mass. Calories are burned more efficiently in bodies that have more muscle. Anaerobic exercise is especially helpful for weight management in that it helps to burn more calories even in a body at rest. Anaerobic exercise can also help build endurance and fitness levels.

If, for example, one of your fitness goals is to lose weight, a program of both aerobic and anaerobic exercise is recommended.

Also, as I’ve mentioned previously, we lose muscle mass and stamina as we get older. This condition is called Sarcopenia and actually starts somewhere around age 30. The primary treatment for this condition is exercise, specifically resistance or strength training exercises like weight training or weightlifting.

In fact, according to the article:

Resistance training has been reported to positively influence the neuromuscular system, hormone concentrations, and protein synthesis rate. Research has shown that a program of progressive resistance training exercises can increase protein synthesis rates in older adults in as little as two weeks.

That certainly sounds promising.

This is me after cardio.

I’ve actually learned a lot in the writing of today’s blog post. I think the takeaway from all this is to realize, especially where cardio is concerned, that there is a practical limit to the intensity level of a duration exercise, or for that matter, a limit to how much distance/time to perform a duration exercise. There may not be immediate problems but the damage could cumulate to a harmful and even dangerous outcome. The same may be true for resistance training, but I’ll have to explore that another time.

As a bonus for today, I’m adding a link to a recent article written by Lou Ferrigno called Fit after 50: How Champs Keep Their Gains, which is certainly relevant to the mission of my “old man’s gym” blog. Enjoy.

There’s a lot more that goes into a comprehensive exercise program for anyone, and particularly for seniors, and in future blog posts, I’ll address those issues. In the meantime, if you have any questions or suggestions on any particular topics you’d like me to write about related to senior fitness, leave a comment here or send me an email using the form on the About Me page.

Success isn’t owned, it’s leased, and rent is due every day.

J.J. Watt


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