Beta-Blocker, Age-Predicted Max, and a Wrist Monitor in Cycling

Keep both pedaling at a self-selected effort, and switch the class's primary gauge from the board to the talk test and RPE.

• 58-year-old (metoprolol): her 108 is not evidence she is underworking. Beta-blockade lowers both resting and exercise heart rate, so 108 may sit near her true ceiling. Ask for RPE on a 0-10 or 6-20 scale - she says she feels like she is working hard, so accept that. Ask about dizziness, chest pain, unusual breathlessness, and calf or chest tightness. Keep her at a gear and cadence she can sustain while speaking a short sentence, and do not chase a zone on the board.
• 24-year-old (188): 188 against 220-minus-age (196) is about 96%, which is plausible for a short climb in a fit young adult - and wrist optical monitors frequently lock onto cadence rather than pulse. Ask him to talk: if he can speak a short sentence and reports no symptoms, he continues. If he reports dizziness, chest pain, or vision change, he stops immediately and you follow your emergency action plan.
• Class-wide: state aloud that today's effort is set by the talk test and how you feel, not by the numbers on the board. Do not discuss either participant's medical details on the microphone.

Two separate errors stack on top of each other.

1. The formula itself is a population average. 220-minus-age has a standard deviation of roughly 10-12 beats, so any individual's true maximum can sit well above or below the prediction. Percentage-of-predicted-max therefore mislabels absolute intensity even in unmedicated participants.
2. The medication changes the response, not the effort. Metoprolol blunts sympathetic drive to the heart, so heart rate rises less at any given workload. Her heart rate at a high percentage of her true capacity can look like a warm-up on the board. The relationship the zones assume - heart rate tracks oxygen uptake - is broken.

Substitutes, in order of practicality in a group class: RPE anchored to familiar language ('somewhat hard,' 'hard but sustainable'), the talk test (can she speak a sentence?), and mechanical output you can see - cadence, resistance, and posture. Where the facility wants heart-rate-based programming, the answer is an individualized plan built with her physician's clearance and medication list, not a generic chart. Use the zones as relative guidance anchored to RPE descriptions rather than as absolute targets.

Immediate follow-up (private, after class):

• Speak with her one-to-one. Ask what her physician has told her about exercise intensity, confirm she has been cleared, and give her an RPE-based way to self-monitor. Do not advise her to change or skip medication - that is prescribing.
• Follow your facility's protocol for participants with known cardiovascular medication use; if it requires written clearance for vigorous intensity, obtain it before her next class, and modify to moderate intensity in the interim.

System changes to raise with management:

• Add medication fields to the health-history form, plus a prompt to seek medical clearance when a participant reports a controlled condition or cardiac medication. A PAR-Q+ style screen would have surfaced this at enrollment.
• Replace or supplement the posted percentage-of-max zones with RPE and talk-test anchors on the studio wall, so the chart does not drive the class.
• Note the limitation of wrist optical monitors in the instructor briefing and in participant orientation.
• Document the conversation in the participant file per policy. Documentation of screening and modification is the practical evidence of reasonable care if a cardiac event occurs later.