What’s the best cardio workout? Is it different for each individual? Both are common questions, and we decided to dig into the data.

This in-depth post summarizes an experiment we conducted with a variety of workouts – from free YouTube workouts to your standard gym equipment to professionally designed routines.

It was interesting to learn that for us, the best cardio workouts are 60-90% more effective for weight loss than the worst.

In my case, if I did the worst workout instead of the best for a year, I would leave 23 pounds of weight loss on the table. Or, if I wanted to lose 23 pounds, it would take me 78 additional hours or 3.25 days!!

The experiment opened our eyes to the importance of working out smart. So, you want to know what’s the best cardio workout? Let’s dive into the experiment.

what is the best cardio workout ryan and alex duo life

what is the best cardio workout?

Alex and I have always been fans of working out together. There are many incredible benefits of working out with your partner.

When we started sweating it out together, it quickly became clear that our bodies responded very differently to different forms of exercise.

It was eye opening to see Alex’s heart rate peaking during a run when I needed to do a high intensity workout to see the same result.

Since we’re engineers (and control freaks) we wanted to collect the data and make sure that we were doing the most effective cardio workouts.

Afterall, cardio is not that fun, so we wanted to make sure we were maximizing our results in the least amount of time.

So, we designed a cardio experiment. In this article, we’ll share the experiment details, results, and takeaways. Keep in mind, the experimental results are our own. Yours would be different. 

Therefore, we share all of the experimental details so that you can replicate it and determine which form of cardio is best for your body. 

The Best Cardio Experiment

In this section, we will outline (in great detail) the details of our experiment.

We discuss the goal of the experiment, our hypothesis, the workouts we did, and the variables that we controlled to get accurate results. 

Cardio Experiment Goal

I have always been a fan of high-intensity cardio workouts. I started running at a young age, ran cross-country competitively, and played soccer year-round throughout high school.

Alex has also been a lifelong fan of cardio workouts, but she refers to herself as a “one-speed pony.” She has never liked the high-intensity workouts as much as I do and prefers running, swimming, and lifting weights.

Workout preferences aside, the purpose of this experiment was to identify the best, most effective cardio workout. Since we’ll be using heart rate analysis, our definition of “the best, most effective workout” is the workout that burns the most calories.

We will measure calories burned during the 20-minute workouts and for 60 minutes immediately after for the “afterburn effect.” We understand that there is more to a workout than just calories burned, but for experimental purposes, this was our best metric.

Our Hypothesis

So, based on our experience, what do we think is the best cardio workout? Probably the workout that has the fastest pace, fewest breaks, and engages the most muscle groups, because that will burn the most calories.

“I am confident that the Beachbody On Demand cardio workouts are going to be the best. It is total body, explosive cardio, they are designed by world-renowned trainers and a team of sports scientists, and they include only enough breaks to prevent you from fainting. I think HIIT will take the cake, and I have never been impressed with workouts on YouTube” – Ryan

“Although I love running and enjoy spin classes, I don’t think either will be the best cardio workouts. They don’t engage enough muscle groups, and they are less explosive than High-Intensity Interval Training (HIIT). I know nothing about the YouTube workouts, but I expect some form of HIIT to win.” – Alex

We have experience doing a variety of HIIT workouts and even designed an at-home, total-body HIIT routine for couples.

About The Experiment

This was a highly detailed experiment to determine what the best cardio workout is. We did our best to control all variables from diet to sleep quantity to hydration to alcohol consumption.

We’re all unique individuals, and our results could be different than yours. In this post, you have everything you need to repeat the experiment and find out what is the best cardio workout for you.

If you plan to repeat the experiment, or if you’re just geeks like us, below are the detailed controls and variables. If you’re not, skip down to the results section.


Workouts (20 minutes of each):

Note – If there was a warm-up included in the routine, that was skipped. Instead, we followed a consistent warm-up for all workouts summarized in the “Controls” section below.


  • Ryan – 30 years old, 175 lbs, 7% Body Fat Composition (collected using this caliper), and intermediate/advanced fitness ability according to our fitness test
  • Alex – 30 years old, 105 lbs, 18% Body Fat Composition, and intermediate/advanced fitness ability

Days: One workout a day in randomized order (see Appendix V).



  • No alcohol during experiment or two days before the start, although, typically drinking is fine in moderation
  • 8-9 hours of sleep tracked using the Pillow app (see sleep data in Appendix III)
  • Followed portion control container plan during the experiment (see food details and tracked containers in Appendix IV)
  • Morning workouts between 8:30 and 9:30 AM
  • No food or supplements between wake and work out
    • Ryan – 40 ounces of water between wake and work out
    • Alex – 20 ounces of water between wake and work out
  • Collect data with Polar H7 HR Monitor during the 20-minute workout – referred to as “the burn”
  • Collect data with Polar H7 HR Monitor immediately after the workout for 60 minutes while reading by the pool – referred to as “the afterburn”
  • Warm-up for 2.5 minutes (not included in HR data):
    • Run in place (30 seconds)
    • Jumping jacks (30 seconds)
    • Side step twists (30 seconds)
    • Stretch (60 seconds)
  • No other workouts during the experiment
  • No music during workouts

The Best Cardio Experiment Results

The results are in! Based on our analysis, our experimental results are accurate and the data is conclusive. VERY conclusive. 

Graphical Results

The graphs below illustrate a strong correlation between average heart rate and calorie burn during the workouts.

As shown in the graphs, Ryan burns significantly more calories than Alex during a cardio workout, and Alex tends to maintain a lower average heart rate. See Appendix I for the data tables.

The below graphs show the total calories burned (calories during the burn + the afterburn) as a result of each workout. Both BOD Cardio workouts showed the highest calorie burned during the 60-minute afterburn for both Ryan and Alex.

The regression analysis for both data sets is shown in the below plots. The analysis confirms a nearly perfect (R2 = 1) correlation between average heart rate and calorie burn. Therefore, our experimental results are accurate.

Cardio Experiment Results

If you really want to geek out with us, feel free to read the long version of the results. Otherwise, here is a shorter summary of our findings. 

The short version:

So, what’s the best cardio workout for Ryan and Alex?

BOD Cardio 2, Insanity Max:30 Cardio Challenge, was the best cardio work out for both. BOD Cardio 1 was the second-best.

For Ryan, it was 91% more effective than the worst form of cardio, the exercise bike. And for Alex, it was 73% better than her worst cardio workout, the Fitness Blender workout on YouTube.

Let’s translate that data into something more digestible, Chipotle burritos (see what I did there?).

If Ryan did his worst form of cardio instead of his best for one year, he would miss the opportunity to burn an excess of 74 Chipotle burritos in calories. That’s the equivalent of 23 pounds of weight loss.

Similarly, if Alex did the same, she would miss the opportunity to burn an excess of 22 Chipotle burritos in calories. Therefore, she is leaving 7 pounds of weight loss on the table.

Of course, there is no such thing as bad cardio. Just less effective cardio. So, let’s say Ryan loves the exercise bike. That’s fine, but he would need to exercise for an additional 78 hours that year to burn off enough calories to lose 23 pounds. That’s 3.25 days on the bike!

Clearly, there is effective cardio and far less effective cardio. Take the time to find the best cardio workout for you, but when in doubt, HIIT is where it’s at. For more details, our calculations, and the long version, click the toggle below.

The longer version:

For Ryan, BOD Cardio 2, Insanity Max :30,  was…

  • 11% better than BOD Cardio 1, Transform :20
  • 44% better than the treadmill
  • 91% better than the exercise bike
  • 68% better than YouTube Cardio 2, POPSUGAR Fitness
  • 77% better than YouTube Cardio 1, Fitness Blender

For Alex, BOD Cardio 2, Insanity Max :30, was…

  • 7% better than BOD Cardio 1, Transform :20
  • 13% better than the treadmill
  • 30% better than the exercise bike
  • 60% better than YouTube Cardio 2, POPSUGAR Fitness
  • 73% better than YouTube Cardio 1, Fitness Blender

If Ryan did 20-minutes of BOD Cardio 2, Insanity Max :30, five days a week for one year he would burn 169,780 calories. That’s…

  • 16,640 calories, or 15 Chipotle burritos*, more than BOD Cardio 1, Transform:20
  • 51,740 calories, or 47 Chipotle burritos, more than the treadmill
  • 80,860 calories, or 74 chipotle burritos, more than the exercise bike
  • 68,640 calories, or 63 Chipotle burritos, more than YouTube Cardio 2, POPSUGAR Fitness
  • 73,840 calories, or 67 Chipotle burritos (that’s 100 lbs), more than YouTube Cardio 1, Fitness Blender

If Alex did 20-minutes of BOD Cardio 2, Insanity Max :30, five days a week for one year she would burn 56,160 calories. That’s…

  • 3,900 calories, or 4 Chipotle burritos*, more than BOD Cardio 1, Transform:20
  • 6,500 calories, or 6 Chipotle burritos, more than the treadmill
  • 13,000 calories, or 12 chipotle burritos, more than the exercise bike
  • 21,060 calories, or 19 Chipotle burritos, more than YouTube Cardio 2, POPSUGAR Fitness
  • 23,660 calories, or 22 Chipotle burritos, more than YouTube Cardio 1, Fitness Blender

* One Chipotle burrito is 1,095 calories. Flour tortilla, chicken, brown rice, black beans, fajita mix veggies, salsas, cheese and lettuce (no sour cream or guacamole).

Key Takeaways & Conclusions

Clearly, there is such a thing as effective cardio and less effective cardio.

And in our experience, Beachbody On Demand offers the most effective cardio. To work out smarter, we recommend following these tips. Here are our key takeaways from our cardio experiment.

1. Figure out what cardio is best for you

You can only do this by tracking your workouts with your FitBit, Apple Watch, or the highly accurate Polar H7 heart rate monitor.

We used the Polar H7 for accuracy during this experiment, but our Apple Watches are reasonably accurate. We are happy with the series 3 watch for him and for her.

For Ryan, no other form of cardio came close to HIIT, but for Alex, running on the treadmill (8.5-minute mile) was a close runner up.

The exercise bike and YouTube Cardio workouts were poor cardio workouts for both of us (according to the heart rate analysis charts in Appendix II).

The bad cardio workouts are usually slower paced with too many breaks to maintain an elevated heart rate. You’ll know they are bad because they aren’t challenging enough.

And when they are challenging, they continue to work for you even after the workout is over.

Both Ryan and Alex burned more calories during the afterburn (60 minutes after the workouts) with BOD Cardio 1 and 2 workouts (Insanity Max:30 and Transform:20, respectively).

These workouts maintained a high average heart rate (also delivered the highest max heart rates of all workouts) by challenging multiple muscle groups.

Therefore, having total body resistance moves in your cardio routine increases the calories burned in the afterburn. The more with lunges, jumping squats, push-ups, burpees, mountain climbers, and core moves, you can squeeze into your cardio routine, the better.

All the details of this experiment are listed below. Go ahead and repeat it for yourselves. You can do so with a free trial of the Beachbody On Demand workouts.

Update: Since doing this experiment, I trained for and crushed his first marathon (I’d like to thank my coach, Alex). Once I was running outside at a faster pace, I was massively impressed by my heart rate and calorie burn data. It’s likely that the treadmill and 8.5 minute mile pace in this experiment wasn’t challenging enough.

Running changes your body in ways other forms of exercise don’t. We highly recommend running, and while you’re at it, why not a marathon? In this article, we share how to train for a marathon and provide a 3-Month Marathon Training Schedule.

2. Partner up

Let’s face it. Cardio isn’t that fun.

But it can be when you do it as a couple. You gain accountability, push yourselves harder, and boost your attraction to each other. Just to name a few of the benefits of working out as a couple.

Don’t believe us? Recruit your partner and give our couples workout routine as shot.

3. Eat the right amount of calories

Exercise is necessary, but healthy eating is essential. It was important for us to learn that Ryan burns 3X calories compared to Alex while requiring 2X calories from meals.

We know that everybody and every body is different, but this was a significant finding.

After this experiment, we started paying more attention to portioning our meals. This is important because you won’t see results from your cardio if you’re not eating the right amount of fuel.

We share our learnings in our article titled ‘How to Manage Diets as a Couple.‘ If haven’t tracked your calories before, follow the guide in our 30-Day Weight Loss Challenge.

Best Cardio Experiment Notes

In this section, we share our workout summary, day by day. Additionally, we’ll share links to the exact workouts we followed so you can repeat the experiment.

Day 1 – Treadmill

So, what is the best cardio workout?

Today, we started the experiment on the treadmill and ran an 8.5-minute mile pace for 20 minutes. For me (Ryan), it was difficult since I rarely run. Therefore, I was breathing heavy and sweating considerably at the end of the workout.

Surprisingly, the workout did not produce a very high average heart rate, 146 bpm. My lifting and cardio workouts regularly have me in the 150-170 bpm range.

Alex is a great runner, so this was easy for her but also produced a high average heart rate. She even burned more calories in the afterburn than she did in the burn. It was interesting to see how our bodies reacted differently to these workouts.

Running on the treadmill was boring for both of us. We much prefer to run outside. For me, it didn’t help that I was stuck watching a comedy cooking show in Japanese.

Day 2 – YouTube Cardio 1, Fitness Blender

YouTube Cardio 1, Fitness Blender

Today’s workout was a let down for both Alex and I. It was a HIIT workout, which is my favorite form of cardio, but the exercises were too short and separated by too many breaks. Therefore, our average heart rate was very low. For me, 130 bpm and for Alex, 115 bpm. This is much lower than yesterday’s treadmill workout.

This might be a great workout for the beginner, but for us, they were far too easy. It’s definitely not going to be the best cardio workout.

Alex also found the video to be misleading as it promised 188-375 calories burned (shown right on the screen). She topped off at 67 calories burned instead.

Day 3 – BOD Cardio 2, Insanity Max :30, Cardio Challenge

BOD Cardio 2, Insanity Max :30, Cardio Challenge

Day 3 was insane, hence the name Insanity. The Insanity Max:30 Cardio Challenge delivered a high average heart rate and calorie burn for both Alex and me.

It was a major challenge, and during the afterburn, I could tell my body was fighting to recover. I was amazed that I burned 653 calories from a 20-minute workout (including the 60-minute afterburn). Very impressive results for Alex, too, burning a total of 216 calories!

The workout consisted of 45-second moves and three short breaks. I credit these great numbers to the intensity, variety of muscle groups recruited, and the explosive total-body moves.

Day 4 – YouTube Cardio 2, POPSUGAR Fitness

YouTube Cardio 2, POPSUGAR Fitness

Today’s cardio workout was another free YouTube workout let-down, as you can see from Alex’s post in our Duo Life Community. It was just….


For us, slow also means boring, and that is never a good thing when it comes to workouts. They are hard enough to be consistent with when they are exciting, challenging, and bringing results.

This is another beginner’s workout, in our opinion. Maybe selecting free workouts based on the number of YouTube views was not the best choice.

I burned 68% fewer calories, and Alex burned 60% fewer calories than yesterday’s BOD Cardio 2, Insanity Max:30, workout. Wow, that would add up to a ton of calories after a few months of working out!

Day 5 – BOD Cardio 1, Transform :20 Sample Workout

BOD Cardio 1, Transform :20 Sample Workout

Today’s cardio workout was a burner! This was the first time ever doing this workout for both Alex and I. And, it took some focus to do the moves properly. Both of us hit our highest heart rate maximum yet! For me, 189 bpm, and for Alex, 170 bpm.

This routine requires a step, and that definitely increases the difficulty level and challenges the muscles in each leg (glutes especially) individually. Core exercises are a major component too. Since we were seated on the step doing core moves quite frequently, I was surprised that we maintained such a high average heart rate.

This cardio workout challenged not only our heart and lungs but also upper, lower, and core muscles. We both hit muscle failure in the 20 minutes so that is very impressive.

Day 6 – Exercise Bike

Today we followed the exercise bike program outlined in Appendix VI. As I reported to our Duo Life Community, this workout took me by surprise. I sweated like crazy, probably because my leg muscles were firing on the many steep hills built into the program.

Unfortunately, my heart rate dropped off quickly after the workout finished, and it ended up being the worst cardio workout for me. This surprised me as I thought it was far harder than the free Youtube workouts. However, this shows that muscle engagement during cardio workouts is critical. The exercise bike is not the best cardio work out.

Alex thought the exercise bike was pretty easy, which is interesting because, according to the heart rate analysis, it was a better cardio workout for her than the YouTube Cardio workouts. This just goes to show that everyone is unique! And it never hurts to have a heart rate monitor!

appendix i

Experiment Data Tables:

Appendix ii

Click below to see all heart rate analysis graphs from our Polar H7 heart rate monitors using the Polar Beat app. Heart rate analysis for Ryan and Alex is shown for the burn and afterburn.

View All Heart Rate Analysis Graphs

what's the best cardio workout heart rate analysis youtube cardio 1 burn
what's the best cardio workout heart rate analysis youtube cardio 1 afterburn
what's the best cardio workout heart rate analysis youtube cardio 2 burn

what's the best cardio workout heart rate analysis youtube cardio 2 afterburn
what's the best cardio workout heart rate analysis exercise bike burn
what's the best cardio workout heart rate analysis exercise bike afterburn
what's the best cardio workout heart rate analysis treadmill burn
what's the best cardio workout heart rate analysis treadmill afterburn
what's the best cardio workout heart rate analysis bod cardio 1 burn
what's the best cardio workout heart rate analysis bod cardio 1 afterburn
what's the best cardio workout heart rate analysis bod cardio 2 burn
what's the best cardio workout heart rate analysis bod cardio 2 afterburn

Appendix III

Pillow App Sleep Data:

appendix iv

Portion Control Container Tracking:

  • Ryan: 7 green, 3 purple, 5 red, 4 yellow, 1 blue, 1 orange, and 6 tsp allowance
  • Alex: 3 green, 2 purple, 4 red, 2 yellow, 1 blue, 1 orange, and 3 tsp allowance

Typical foods:

We eat a mostly vegetarian diet (fully for Alex) of organic whole foods. We also stick to a 16/8 intermittent fasting plan.

For more details on healthy eating, see our Eat Clean Page.

Appendix v

Randomization of workout order:

Appendix vi

Program settings for the exercise bike (LifeFitness brand):

  • Select the Classic Cardio program (a random mixture of gradual and steep hills)
  • Ryan: Difficulty level 13 of 25 for 20 minutes
  • Alex: Difficulty level 9 of 25 for 20 minutes
  • Maintained 70-100 rpms
  • Never fell below 70 rpms (about 15 mph) on steep hills, and usually never fell below 75 rpms

Pictured below.

Closing Thoughts

So, what’s the best cardio workout?

Based on this data, total body HIIT. It should be fast-paced, incorporate bodyweight strength training, and keep you in zones 3, 4, and 5 for nearly the entire workout. It should be really hard, but you only have to do it for 20-30 minutes.

If you want effective cardio, there are a variety of great programs on Beachbody On Demand. Below is our review of Beachbody On Demand and once you sign up, these are the best (most effective) Beachbody workout programs

If you have any questions about our experiment, ask away in the comments below.

For more helpful fitness resources, such as our 30-Day Ab Challenge, our guide on how to build a home gym, or the free 8-Week Resistance Band Workout Routine, head over to our Work Out At Home Page.

Bodyweight Workout Plan Form V2 Ryan and Alex Duo Life

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  • A program guide built for your current fitness level: beginner, intermediate, or advanced.
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As Seen In Feature Bar Ryan and Alex Duo Life

Hey we're Ryan and Alex

The creators of Ryan and Alex Duo Life. We are a husband-wife duo and “lifestyle engineers.”

After eight years working in the corporate world as engineers, we left our high-powered jobs to tackle our true passion — helping couples engineer their best lives.

The synergy of our engineering minds and ten years of health coaching experience produced Ryan and Alex Duo Life. Our mission is to help you transform your bodies, minds, and relationship as a couple.

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