To maximize the benefits of cardio, understanding and managing workout intensity is crucial. Improving cardiorespiratory fitness hinges on how ‘hard’ you work during aerobic exercise. Higher energy expenditure translates to greater fitness gains. But how do you gauge ‘hard’? Heart rate is an excellent indicator of exertion. Monitoring it ensures you’re working hard enough to improve your cardiorespiratory fitness.
Your Training Heart Rate (THR) reflects the intensity needed for a training effect. Two common methods, recommended by fitness experts, help determine THR: the ‘% Maximum Heart Rate’ (%MHR) method, simpler to use, and the ‘% Heart Rate Reserve’ (%HRR) method, which is more accurate.
**%MHR Method**
This method estimates your maximum heart rate (MHR) by subtracting your age from 220. For instance, a 20-year-old’s estimated MHR is 200 BPM (220 – 20 = 200).
Exercise intensity should align with your fitness level: 70% of MHR for those in poor shape, 80% for those in good shape, and 90% for those in excellent shape.
*Examples:*
* A 20-year-old in good shape: THR = 160 BPM (220 – 20 = 200 * 0.80 = 160 BPM).
* A 30-year-old in good shape: THR = 152 BPM (220 – 30 = 190 * 0.80 = 152 BPM).
* A 40-year-old in poor shape: THR = 126 BPM (220 – 40 = 180 * 0.70 = 126 BPM).
**%HRR Method**
A more precise approach calculates THR using heart rate reserve (HRR). Exercising within 60-90% of your HRR effectively improves cardiorespiratory fitness. Adjust the percentage based on your fitness level: start at 85% HRR for excellent condition, 70% for reasonably good shape, and 60% for poor shape.
Most cardio workouts should target 70-75% HRR to build or maintain fitness. Highly fit individuals may benefit from higher percentages, especially with limited workout time.
Exercising below 60% HRR might not provide sufficient stimulus, while exceeding 90% can be risky. Determine your THR before starting any aerobic training program.
To calculate THR using %HRR, you’ll need your resting heart rate (RHR).
*Example: A reasonably fit 20-year-old*
* STEP 1: MHR = 220 – 20 = 200.
* STEP 2: Measure RHR (resting pulse for 30 seconds, multiplied by two). Let’s assume RHR = 69 BPM.
* STEP 3: HRR = MHR – RHR = 200 – 69 = 131 BPM.
* STEP 4: Calculate THR: (1) 0.70 * 131 = 91.7, (2) 91.7 + 69 = 160.7.
Therefore, a reasonably fit 20-year-old with a RHR of 69 BPM has a THR goal of 161 BPM.
During cardio, a ‘Steady State’ is typically reached after five minutes, with heart rate leveling off. Monitor your heart rate at this point, and immediately after exercise, to ensure you are within your desired THR range. Increase intensity if your pulse is below THR, and reduce intensity if it’s above.