Best Fitness Indicator, RHR

Resting Heart Rate As Fitness Indicator

Is crossfit, SS, or 5x5 good cardio

Resting heart rate is a very good indicator of overall cardiovascular fitness level and overall health. People with low resting heart rates cut their risk of diabetes in half and reduce their risk of heart attacks by and are less likely to die of heart attacks too. Highly trained athletes have very strong hearts that when resting can supply the bodies needs with a very slow heart rate. In contrast, the weaker hearts of untrained and out of shape people have to work much harder just to supply the resting bodies needs.

There are a lot of people who hate doing cardio and believe anyone who gives them valid excuses to avoid cardio or minimize the time they spend doing cardio. Many young adults who do strength training have been brainwashed to believe that “cardio kills muscular gains” so they don’t do it at all. Many people who do Starting Strength (SS), Crossfit, or Stronglifts 5×5 believe their weight workouts are “so intense” that they qualify as cardio. Based on one flimsy research study, many believe that 8 minutes of Tabata intervals is “good cardio” and that linear cardio like jogging or cycling is a “waste of time”. The late night infomercial ab machines are notorious for promising health and rock hard abs with just a few minutes a day. The $14,000 ROM-cycle in my Fitness Hall of Shame touts washboard abs and top health with their “research proven” 8 minute workout. Sixpackshortcuts, also in my Fitness Hall of Shame promotes his “shortcut” to abs, by you guessed it, claiming cardio is a waste of time. Everybody is looking for a shortcut.

For all you people who disagree with me and still think your weight workout or your 15 minutes of interval training is good cardio, here is a reality check. Measure your resting heart rate right now. Yep, now – what is it? Where do you fall in Scooby’s bro-science chart below?

Resting Heart Rate (RHR)
Age Improvement Needed     Elite Endurance Athlete
15-25 over 60BPM 35-50 BPM
25-45 over 65BPM 40-55 BPM
45-60 over 70BPM 45-60 BPM

If your resting heart rate (RHR) puts you in the elite athlete category, congratulations! Your cardio workout is awesome. If your heart rate puts you in the “Improvement Needed” category then you have some work to do if you want to live a long and healthy life. In my experience, interval training cardio workouts like HIIT and Tabata help you sprint faster but linear, endurance cardio durations over 30 minutes I have found do a much better job of cardiovascular conditioning. Examples of this type of cardio are doing daily brisk walking, jogging, swimming, or cycling.

Please post your RHR and cardio workout here!

Its no secret that I push cardio hard and I advise people that if they only have time to do either weights or cardio that they skip the weights and focus on cardio. Why? Because in my opinion, cardio is the #1 most important thing you can do to live a longer, healthier, and leaner life.

Time for a little more “Scooby bro-science” here and my theory about why cardio is good for you. We all know cardio is important for weight loss, for reducing stress, and for improving mood. Those things by themselves can increase your lifespan and quality of life but lets look at another way cardio helps – by making your heart last longer. My engineer’s view of the heart is that it is a “machine” with moving parts and it has a finite life. A heart can only beat so many times before it wears out and then it cant pump any more. Minimize pumps per day will maximize lifespan. So how does this relate to exercise? Many people might reason from this that exercise is bad because your heart races during exercise but lets look at why this is incorrect:

  • Person 1: Me. I do an hour of cycling or running a day at 70-90% of my max heart rate. While exercising, my heart rate averages about 150 BPM. While at rest, my heart rate is 47-52 BPM depending on the day.
    • 150×60=9,000 beats during an hour of exercise
    • 52x60x23= 71,760 beats during resting 23 hours
    • = 80,760 beats per day
  • Person 2: Sedentary. Never walks when they don’t have to and takes elevator instead of stairs. Their resting heart rate is 85, fairly normal for a sedentary and overweight non-athlete.
    • 85x60x24= 122,400 beats per day.

So notice that while my heart gets up to 150BPM while exercising, my cardiovascular conditioning keeps my resting heart rate very low so that when you calculate the beats per day, mine are far less than the sedentary person. My heart beats 34% fewer times per day than the sedentary person. If all else were equal in this example, he would live to be 65 and I would live to be 98.

Many would argue that 30-60 minutes of daily cardio is “wasted time” that could be better spent working overtime, fishing, or whatever. Lets continue my Scooby bro-science a bit further and calculate the “return on investment” of our cardio. Lets say that Person 2 were willing to start “wasting” an hour a day to do cardio and that that thru their cardio they were able to get their RHR down from 85BPM to 52BPM. In that case, every single day they would save 122400-80,760 = 41,640 heart beats – thats 12 hours worth of heart beats with their new, lower RHR! “Waste” one hour exercising and you gain 11 hours of lifespan – an incredible 11:1 return on your time spent!

Could a sedentary, overweight person really drop their RHR from 85 to 52? Maybe, but probably not. They would have to be *really* motivated to do this and it would require making fitness and health the #1 priority in their life. Whats more realistic and achievable for the average out of shape person with average motivation? Probably dropping their resting heart rate by about 20 BPM is easy and doable for anyone. If you recalculate the numbers for this more average case, you get each hour spent doing cardio buys you 7 hours of extended life expectancy – still an incredible 7:1 return on your time investement!

So, back to the real world. Will I really live 34% longer than sedentary person 2? Very unlikely. Why? Because there are about a kazillion things that will probably kill me before my heart gives out: a plane crash, being crushed by a meteorite, a texting driver hitting me while I’m jogging, cancer – the list goes on and on.

Control in life the things you can and don’t worry about things you cant. Eat healthy and exercise! And please, stop looking for excuses to avoid doing your daily 30 minutes of cardio!!!

biking 56 miles at half ironman


Temporal Changes in Resting Heart Rate and Deaths From Ischemic Heart Disease

Direct relationship between RHR and coronary mortality:

Elevated RHR double chance of diabetes:

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