Prescribing physical activity to prevent and manage gestational diabetes

Table 2 Example using heart rate reserve to determine target hazard ratio range

Target HR range (40%-89% HRR)

Example patient: 30-year-old female

Resting HR: 78 beats per minute (bpm)

Maximum HR: 190 bpm (estimated as 220 minus age)

Formula for sample calculation:

Target HR = [(Max HR-Resting HR) × Desired Intensity)] + Resting HR

Lower end of HR range (40%) = [(190-78) × 0.40] + 78

(Low end of moderate intensity) = [112 × 0.40] + 78 = 45 + 78 = 123 bpm

Higher end of HR range (89%) = [(190-78) × 0.85] + 78

(High end of vigorous intensity) = [112 × 0.89] + 78 = 100 + 78 = 178 bpm

Target HR range (40%-89% HRR) = 123 to 178 bpm

HRR: Heart rate reserve.