4.4 Cardiorespiratory Testing, KPIs, and Reassessment

4.4 Cardiorespiratory Testing, KPIs, and Reassessment

Quick Answer: Finish Domain 1.C by testing cardiovascular capacity (1.C.3), then interpret the whole battery, finalize goals and KPIs with the client (1.C.4), schedule reevaluation (1.C.5), and refer unexpected findings (1.C.6). Prefer submaximal cycle, treadmill, step, and Rockport walk tests. Laboratory VO2max is the gold standard; gym tests estimate it. Chest pain, dizziness, or an abnormal BP response ends the test.

Cardiorespiratory testing tells you how well the client can sustain work. Combined with sections 4.1–4.3, it becomes a file you can actually program from—if you interpret it with the client instead of mailing a verdict.

Submaximal Field Tests vs. Laboratory VO2max

VO2max is the maximal rate of oxygen uptake, usually expressed in ml/kg/min. In a laboratory, open-circuit spirometry during a graded test to voluntary exhaustion is the reference method. CPT studios almost never have that cart. You will use submaximal tests that estimate VO2 from heart rate, time, or recovery pulse.

Expect error on the order of about 10–15% on many field estimates. That is still useful for tracking change in the same client on the same protocol. It is a weak reason to rank a client against an unpublished national chart you cannot source. If an exam item prints an ACSM or textbook rating table, use the table in the item and name it as a commonly used field table—the exam still cares more about procedure and interpretation than about memorizing one chart.

Age-predicted maximal heart rate (APMHR) is often 220 − age. It is an estimate with wide individual scatter, but submaximal protocols still use it as a ceiling.

Worked example: 45-year-old client. APMHR = 220 − 45 = 175 bpm. Typical YMCA-style submax guidance keeps heart rate between about 110 bpm and 85% APMHR. 0.85 × 175 = 149 bpm. If HR exceeds that band, you stop increasing workload. 70% of 175 = 123 bpm, a moderate landmark some walk tests hover near.

Common CPT options:

Rockport / Kline-style equation (commonly used field formula; gender = 1 male, 0 female):

VO2max (ml/kg/min) = 132.853 − (0.0769 × weight in lb) − (0.3877 × age) + (6.315 × gender) − (3.2649 × time in minutes) − (0.1565 × HR)

Worked example: 40-year-old woman, 150 lb, mile in 15:30 (15.5 min), ending HR 148 bpm, gender = 0.

0.0769 × 150 = 11.535
0.3877 × 40 = 15.508
3.2649 × 15.5 = 50.606
0.1565 × 148 = 23.162
Sum to subtract = 100.811
VO2max ≈ 132.853 − 100.811 = 32.0 ml/kg/min

Tell the client: this is an estimate from a walking test, useful as a baseline. A laboratory VO2max could read higher or lower. The 12-week win is a faster mile or a lower ending HR at the same time, not chasing a decimal.

Beta-blockers and some other cardiac meds blunt HR. HR-based VO2 estimates then fail. Switch to RPE and the talk test, and coordinate with the physician.

RPE and the Talk Test

Borg 6–20 scale (commonly taught): 6 is no exertion, 20 is maximal. Moderate work often sits near 12–13; vigorous near 14–17. Pair the number with a phrase the client understands (easy, somewhat hard, hard).

Talk test:

• Can speak comfortably in full sentences ≈ below the first ventilatory threshold (often a moderate ceiling).
• Can speak but not sing, broken sentences ≈ moderate to vigorous transition.
• Cannot speak more than a word or two ≈ high intensity; not a submax-test target for deconditioned clients.

Use these when HR is untrustworthy or when you are teaching the client how hard a zone should feel after the test.

Interpreting the Whole Performance Evaluation

DCO 1.C.4: interpret structural, functional, and fitness results together, then finalize goals with the client and establish KPIs.

Interpretation is a conversation, not a lecture:

• Resting BP 132/84 (ACC/AHA 2017 Stage 1 screen) plus a waist of 39 in plus a 16:20 mile is a cardiometabolic pattern. The goal may be walking capacity and waist change, and a physician follow-up for the BP—not a surprise 1RM week.
• A 200 lb estimated bench with overhead-squat valgus means strength exists in one pattern and control does not in another. KPI the squat pattern before the squat max.
• A high BMI with a small waist and a 28-inch vertical jump is often muscle. Do not shame the BMI; pick better KPIs (girth, jump, work capacity).

Goals must be the client’s goals, edited for safety. You may know the mile should get faster; they may care about a hike in 12 weeks. Write both: the hike is the outcome, the mile time is the KPI that predicts it.

Establishing KPIs

A key performance indicator is a number you can retest with the same protocol. Good KPIs are specific, timed, and tied to a test you already ran.

Worked 12-week KPI set from one baseline file:

Three KPIs beat twelve. Pick the ones that serve the stated goal. Do not KPI a 1RM the client is not cleared to test.

Scheduling Reevaluation

DCO 1.C.5: establish a schedule and conduct reevaluation.

Common field windows (adjust to the client, not to a secret NSCA calendar):

• Skill and endurance (push-ups, walk time, squat pattern): about 4–8 weeks.
• Body composition and waist: about 8–12 weeks so you are not chasing menstrual-cycle or glycogen noise.
• True 1RM: only when technique and clearance still allow it; not weekly.

Retest the same way: same cuff, same walk course, same metronome, same squat depth, same time of day when practical. Bring the old numbers to the session so the client sees change. If nothing moved, that is data for program modification (Chapter 7), not a reason to invent a new test that cannot be compared.

Referral from Unexpected Findings

DCO 1.C.6: refer and collaborate when the performance evaluation produces findings outside a normal exercise response.

Stop the test. Then refer or activate the emergency action plan as the signs demand. Do not finish the stage to keep a VO2 estimate.

Red flags during or after testing (commonly taught ACSM-style termination ideas; label them as such):

• Chest pain, tightness, or anginal equivalents (jaw, arm, unusual shortness of breath).
• Dizziness, near-syncope, confusion, nausea, pallor, or cold sweat.
• Abnormal BP response: systolic pressure that fails to rise or falls (≥10 mm Hg drop is a classic stop rule) as workload increases; diastolic pressure that rises excessively. Commonly cited ACSM-style excessive BP stop values are systolic >250 mm Hg or diastolic >115 mm Hg—treat those as commonly used clinical termination numbers, not a trivia flex.
• Heart rate that fails to increase with increasing work, or an irregular rhythm you cannot explain.
• Claudication, wheezing that is new, or oxygen desaturation if you are monitoring it.
• Client requests stop. That request is a valid termination.

Worked example: During a treadmill walk, the client reports chest tightness and lightheadedness. The last BP is 188/102. You stop, seat or lay the client per EAP, do not start a cool-down jog, and activate EAP / emergency services as indicated. You do not compute Rockport VO2 from a partial, symptomatic trial. After medical evaluation, you re-enter only with written clearance and a revised test (often RPE-limited walking).

Unexpected resting findings belong here too: new Stage 2-range BP, unexplained tachycardia, or a functional screen that looks like acute injury. Use the allied-health network. Document what you saw, what you stopped, and whom you contacted.