Exercise Prescription
Build the prescription with FITT-VP
Frequency, intensity, time, type, volume in MET-minutes per week, and progression. Baseline target is 150 min/week of moderate activity (40-59% heart rate reserve, RPE 11-13, talk test still possible) or 75 min/week vigorous (60-89% HRR, RPE 14-17), roughly 500-1000 MET-min/week. Add resistance training 2 days/week (2-4 sets of 8-12 reps at 60-70% 1RM) and flexibility 2-3 days/week.
Intensity calculations
Karvonen: target HR = (HRmax - HRrest) x %HRR + HRrest. Use heart rate reserve, not percent of maximal heart rate, whenever the stem specifies the Karvonen method.
Special populations
CAD and heart failure: start low, progress slowly, supervise high-risk patients, and use interval work when steady vigorous work is poorly tolerated. Hypertension: avoid heavy resistance and Valsalva. Diabetes: check glucose before exercise if on insulin, take carbohydrate if under 100 mg/dL, and watch for delayed post-exercise hypoglycemia. Post-CABG: sternal precautions for 6-8 weeks with limited upper-body loading. Beta-blockers blunt heart rate, so use RPE and symptoms.
Traps
Using percent HRmax when the stem says HRR; prescribing three days a week when guidelines say most days; omitting the cool-down in patients with CAD; exceeding heart rate limits in ICD patients, where exercise HR should stay 20-30 bpm below the detection threshold.
Worked example
A 50-year-old has a resting HR of 70 and predicted HRmax of 170, so HRR = 100. At 40-59% HRR the target range is 110-129 bpm.