Target Heart Rate During Exercise
For moderate-intensity exercise, heart rate should increase to 50-75% of maximum heart rate (calculated as 220 minus age), which translates to approximately 40-60% of heart rate reserve for most individuals. 1
Recommended Heart Rate Targets by Method
Primary Method: Percentage of Maximum Heart Rate
- Moderate intensity: 65-75% of maximum HR (or 55-64% for unfit patients) 1
- High intensity: Up to 85% of maximum HR 2
The maximum heart rate is estimated as 220 minus age, though this has considerable variability (±10-15 beats per minute) 3
Alternative Method: Heart Rate Reserve (HRR)
For patients with exercise test data, a more precise approach uses heart rate reserve:
- Moderate intensity: 40-60% HRR = [(max HR - resting HR) × 0.40-0.60] + resting HR 2
- High intensity: Up to 85% HRR 2
Age-Specific Target Ranges (American Heart Association)
For older adults exercising at moderate intensity (50-75% of maximum): 1
- Age 60: Target 80-120 bpm (max ~160 bpm)
- Age 65: Target 78-116 bpm (max ~155 bpm)
- Age 70: Target 75-113 bpm (max ~150 bpm)
- Age 75: Target 73-109 bpm (max ~145 bpm)
Practical Application
The heart rate should increase approximately 10 bpm per metabolic equivalent (MET) during progressive exercise 4. This linear relationship helps gauge appropriate intensity progression.
Alternative Intensity Markers When Exercise Testing Unavailable
If no formal exercise test has been performed:
- Use Borg Rating of Perceived Exertion (RPE) of 12-14 on the 6-20 scale (described as "somewhat hard") 1, 2
- Apply the "talk test": able to speak but not sing comfortably during exercise 1
Simplified Method for Cardiac Rehabilitation
For patients without exercise test data, resting heart rate plus 30 bpm is more effective than resting HR plus 20 bpm, though this still underestimates optimal intensity for many patients 5, 6. This method approximates 60-70% of maximum heart rate 6.
Critical Considerations
Medications matter: Beta-blockers and other cardioactive drugs significantly alter heart rate response, making percentage-based targets unreliable 2, 7. In these cases, rely on RPE and functional capacity measures instead.
The 1:2 duration ratio (40 minutes moderate vs 20 minutes vigorous) recommended in guidelines does not equalize physiological strain—vigorous exercise produces greater strain regardless of the shortened duration 8.
Prognostic markers during exercise 9:
- Resting HR >75 bpm increases sudden death risk
- HR increase <89 bpm during exercise increases sudden death risk 6-fold
- HR recovery <25 bpm one minute post-exercise doubles sudden death risk
These findings emphasize that both the magnitude of heart rate increase during exercise and the rate of recovery afterward carry important health implications beyond simple training effects.
Progression Strategy
Start conservatively at 40-60% heart rate reserve for the first 3 weeks, then progress to 50-80% as tolerance improves 1, 2. Increase duration before increasing intensity to minimize cardiovascular stress 1.