Shallow-Water Class With a Participant on Beta-Blockers
You teach a 45-minute shallow-water cardio class (water 1.1 m, chest depth) at a community pool, 14 participants, water 30 °C, air 26 °C. A regular, a 62-year-old man with hypertension, mentions before class that his doctor started him on a beta-blocker two weeks ago. He says he feels fine and wants to 'push hard today.' During the warm-up you notice he is not sweating despite the warm water and is talking less than usual, though he reports a perceived exertion of only 4 out of 10. His face is flushed. He is not in distress and is breathing normally. The class plan includes three 4-minute high-intensity intervals with arm-and-leg combos.
1. What is the central safety concern, and how should it change your interpretation of his self-reported exertion?
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Beta-blockers blunt heart-rate response and can mask the tachycardia and other adrenergic signs that normally signal rising exercise intensity. His RPE of 4 is therefore unreliable as a load indicator, and the absence of sweating plus flushing in 30 °C water are more informative than his own rating. The judgment call is to not treat 'feels fine' as clearance for high-intensity intervals. Use observable signs (breathing, talk test, skin, coordination) and err toward lower intensity. Document the medication disclosure and your modification.
2. How would you modify the session for him while keeping the class running, and what is your escalation threshold?
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Offer a parallel lower-intensity track: he performs the same movement patterns at moderate pace, taking the recovery option during each 4-minute interval (e.g., continuous steady work instead of surges), with permission to self-pace. Keep him where you can see him and near the shallow end. Escalate-stop him, move to the deck, monitor breathing and responsiveness, and seek medical help-if you see disproportionate breathlessness, dizziness, confusion, pallor, chest discomfort, or unusual fatigue. Because he is stable and asymptomatic, this is a modification, not an emergency; but the threshold is set on signs, not on his RPE.
3. What follow-up and documentation steps are appropriate after class?
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Speak with him privately after class, explain why his rating scale is less reliable on a beta-blocker, and encourage him to ask his physician about target intensity guidance. Record the disclosure, the modification made, and any observed signs in the incident/participation log per facility policy. Do not give medical advice or a target heart rate; refer to his clinician. Flag it for the next instructor so the modification carries forward.