Key Takeaways
- Normal resting vital signs: HR 60-100 bpm, RR 12-20 breaths/min, BP <120/80 mmHg, SpO2 95-100%
- Hypertensive crisis: systolic >180 mmHg or diastolic >120 mmHg — hold exercise and notify physician
- Normal exercise response: HR and SBP increase with workload; DBP stays stable or slightly decreases; an SBP drop of >10 mmHg with increasing workload is abnormal (exercise hypotension)
- The 6-Minute Walk Test (6MWT) measures functional exercise capacity; performed on a 30-meter corridor; predicts mortality in CHF and COPD
- Metabolic equivalents (METs): 1 MET = 3.5 mL O2/kg/min (resting oxygen consumption); light activity is 1-3 METs, moderate 3-6 METs, vigorous 6+ METs
- Rate of Perceived Exertion (RPE): Borg 6-20 scale; moderate intensity is 12-14 ("somewhat hard"); 15-17 is hard; correlates with ~60-85% of HR max
- ECG basics: Normal sinus rhythm has regular P-QRS-T complexes; ST elevation indicates acute MI; ST depression indicates ischemia
- Pulse oximetry: SpO2 <90% requires supplemental oxygen and exercise should be stopped or modified
Cardiopulmonary Examination
Physical therapists must be proficient in cardiopulmonary assessment to safely manage patients and prescribe exercise. The NPTE tests your ability to interpret vital signs, recognize abnormal responses, and apply functional outcome measures.
Vital Sign Assessment
Normal Resting Values
| Vital Sign | Normal Adult Range |
|---|---|
| Heart Rate | 60-100 bpm |
| Respiratory Rate | 12-20 breaths/min |
| Blood Pressure | <120/80 mmHg |
| SpO2 | 95-100% |
| Temperature | 97.8-99.1 degrees F (36.5-37.3 degrees C) |
Blood Pressure Classification (ACC/AHA 2017)
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Normal | <120 | <80 |
| Elevated | 120-129 | <80 |
| Hypertension Stage 1 | 130-139 | 80-89 |
| Hypertension Stage 2 | ≥140 | ≥90 |
| Hypertensive Crisis | >180 | >120 |
Exercise Response — Normal vs. Abnormal
| Parameter | Normal Response to Exercise | Abnormal Response (Concern) |
|---|---|---|
| Heart Rate | Increases proportionally with workload | Fails to rise (chronotropic incompetence), excessive rise |
| Systolic BP | Increases with workload | Drops >10 mmHg with increasing workload (exercise hypotension) |
| Diastolic BP | Stable or slight decrease | Increases >15 mmHg above resting |
| SpO2 | Remains >90% | Drops below 90% |
| RPE | Increases with workload | Disproportionately high RPE for the workload |
| ECG | Normal sinus rhythm | ST changes, arrhythmias |
Criteria for Stopping Exercise
Exercise should be stopped immediately if any of the following occur:
- SBP >250 mmHg or DBP >115 mmHg
- SBP drop >10 mmHg from baseline with increasing workload
- SpO2 drops below 88-90%
- New onset of chest pain, severe dyspnea, or dizziness
- New arrhythmia or significant ECG changes (ST depression >2 mm)
- Signs/symptoms of poor perfusion: pallor, cyanosis, confusion
- Patient requests to stop
6-Minute Walk Test (6MWT)
The 6MWT is a sub-maximal exercise test widely used in cardiopulmonary rehabilitation:
Protocol:
- Performed on a 30-meter (100-foot) flat corridor
- Patient walks at their own pace for 6 minutes
- They may slow down or rest but are encouraged to resume walking
- Standardized verbal encouragement is given each minute
- Measure: total distance walked in 6 minutes
Interpretation:
- Normal healthy adults: 400-700 meters (age, gender, height dependent)
- Below 300 meters: Associated with increased morbidity and mortality in CHF/COPD
- Minimal clinically important difference (MCID): ~30-54 meters for most populations
Clinical Use:
- Predicts mortality in CHF and COPD
- Assesses functional capacity for surgical risk
- Monitors response to cardiac/pulmonary rehabilitation
- Serves as a baseline and outcome measure
Metabolic Equivalents (METs)
One MET equals the resting metabolic rate: 3.5 mL O2/kg/min
| MET Level | Intensity | Examples |
|---|---|---|
| 1-2 METs | Very light | Resting, eating, desk work, slow walking (1-2 mph) |
| 2-3 METs | Light | Level walking 2.5 mph, light housework, cooking |
| 3-5 METs | Moderate | Walking 3-4 mph, cycling, golf, raking leaves |
| 5-7 METs | Heavy | Jogging, swimming laps, tennis, shoveling |
| 7-9 METs | Very heavy | Running, vigorous sports, heavy manual labor |
| >9 METs | Near maximal | Competitive athletics, sprinting |
MET Level Clinical Applications:
- Post-MI: Progress from 1-2 METs (ICU) to 4-5 METs before discharge
- Cardiac rehab Phase I: Up to 3-4 METs
- Return to work assessment: Match job MET demands to patient capacity
- Sexual activity: Requires approximately 3-5 METs
Rate of Perceived Exertion (RPE)
Borg 6-20 Scale
| RPE | Perception | Approximate HR Equivalent |
|---|---|---|
| 6 | No exertion | ~60 bpm |
| 9 | Very light | ~90 bpm |
| 12-14 | Somewhat hard (moderate) | ~120-140 bpm |
| 15-17 | Hard (vigorous) | ~150-170 bpm |
| 19-20 | Maximal | ~190-200 bpm |
Clinical Correlation: RPE roughly corresponds to heart rate when multiplied by 10 (e.g., RPE 13 ≈ HR 130). For cardiac patients on beta-blockers (which blunt HR response), RPE is a more reliable measure of exercise intensity than heart rate.
During a graded exercise test, a patient systolic blood pressure drops from 140 mmHg to 125 mmHg as workload increases. This indicates:
The 6-Minute Walk Test is performed on:
A cardiac patient is taking a beta-blocker medication. When prescribing exercise intensity, the PT should primarily rely on:
Approximately how many METs are required for sexual activity?
Match each MET level to the appropriate activity example.
Match each item on the left with the correct item on the right
9 METs