Case Study: Do different exercises have an impact on your fuel utilization when heart rate intensity is maintained?

What Modalities (Exercises) Were Used?

Each session was eight minutes long, wearing a PNOE metabolic analysis device, and performed at an average heart rate of 125 to 130bmp with 10 minutes rest between sessions.

Session one was on the indoor rowing machine; session two on the Air Runner; session three on the ski erg; session four on the bike erg; and session five was a modalities session that included double unders, air squats, deadlifts, and push presses. 

Why Heart Rate Monitors?

There are many different ways to monitor intensity. Ticker Training utilizes heart rate monitors as a simple, effective tool for monitoring stress and training adaptation. This short case study demonstrates that metabolic intensity is the same across different modalities (i.e. exercises) when heart rate is kept consistent, in this case at 130bpm (beats per minute).

Wearing a PNOE metabolic analysis device daily is not realistic nor necessary to implement and follow heart rate–based training. We utilize heart rate monitors during exercise to target time spent in your heart rate training zones, which are determined during your metabolic test. This heart rate–based exercise is the best way for us to monitor and adjust training as adaptation occurs.

Why 130bpm

For this case study, I used my latest personal PNOE metabolic test, which indicated that to improve my aerobic conditioning, I need to do the majority of my training below 130bpm. 

What Where the Results? 

Different exercises had little effect on my metabolic system when I kept my intensity consistent. All exercises were very similar in fuel utilization and were done with an average heart rate of 125bpm. I utilized 34 calories from fat and 43 from carbohydrates for a total of 77 calories. This equated to an RER (respiratory exchange ratio) value of 0.85 (aerobic). 

Below I have attached fuel utilization and intensity graphs and values from the PNOE metabolic analysis. I have also included some of my pacing during the sessions for those familiar with the used modalities.  

What’s Next?

The next question to answer is: Do these results hold true for everyone? My hypothesis is no because I have spent a considerable amount of time practicing and improving my aerobic system across different time domains and exercises. However, I am currently accepting clients interested in testing this hypothesis to see if my results are because of learned practice or if intensity remains the same no matter the modality. Here is a quick video to show pacing and intensity throughout my session.

Session one fuel utilization details

8 minute Row performed at 130bpm

2:10 per 500m pace


8 minute Air Runner performed at 130bpm

10 minute per mile pace

8 minute Ski Erg performed at 130bpm

2:25 per 500m pace

8 Minute Bike Erg at 130bpm

2:08 per 1000m pace

8 Minute Mixed Modal at 130bpm

AMRAP 10 Reps of Each

Double Under

Air Squat


Air Squat

Push Press

Air Squat


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