Effect of bisoprolol and atenolol on endurance exercise capacity in healthy men
Participants & Protocol
n=12 young, healthy, normotensive men
Protocol
Design: the twelve subjects randomly received each treatment in a double-blind crossover (from the abstract)
Double-blind crossover: oral placebo, atenolol 100 mg/day or bisoprolol 10 mg/day, each for 3 weeks
At the end of each period: endurance test on a bicycle ergometer at 70% of maximal aerobic power; cardiac output by CO2 rebreathing; venous blood before, during and after exercise
Key Results
Total exercise duration fell vs placebo with both drugs: bisoprolol −19.4 ± 6.7% (p<0.01), atenolol −29.8 ± 6.6% (p<0.001); the two drugs did not differ significantly (tendency to a smaller reduction with bisoprolol)
Both drugs lowered resting plasma renin activity, heart rate and systolic blood pressure to the same degree
Resting and exercise stroke volume rose, so cardiac output was not significantly affected — haemodynamics are unlikely to explain the loss of endurance
Both drugs blunted the exercise-induced rise in plasma free fatty acids and lowered them in recovery; the reduction in exercise duration was not related to the haemodynamic changes or to the free-fatty-acid impairment, so the mechanism remains unclear
Practical Application (not medical advice)
In 12 healthy young men, 3 weeks of atenolol cut time to exhaustion at 70% of maximal aerobic power by 29.8% and bisoprolol by 19.4% vs placebo, with cardiac output unchanged; the smaller loss with the β1-selective drug was a tendency, not a significant difference. For an athlete on a beta-blocker the reduced endurance is pharmacological, not lost fitness.
Not from this paper; the base's own practice: with resting and exercise heart rate pharmacologically lowered, do not set zones from population max-HR formulas — anchor intensity on power (cycling), pace (running) and RPE, or on an individual test done on the medication; see REF-072 and SYNTH-16 on HR vs power as intensity markers.
Inference, not tested: the abstract does not report maximal heart rate or maximal tests; it shows that submaximal endurance time falls even though cardiac output is preserved.
Limitations
Sample = 12 healthy young men, not masters athletes with hypertension; 3-week periods
Endurance measured as time to exhaustion at 70% of maximal aerobic power on a cycle ergometer — a single submaximal protocol, not maximal capacity
Older study (2000); newer β-blockers (nebivolol with vasodilation) were not tested
How this entry was checked and changed
Why this level
regraded 2026-09-27 from B+: crossover, n=12
Content correction 2026-09-27
Sport "running", "maximal and submaximal endurance tests", "reduced maximal HR and peak performance" -> the abstract reports one cycle-ergometer endurance test at 70% of maximal aerobic power; maximal HR was not reported (resting HR was lowered).
Added the abstract's numbers: n=12, doses (atenolol 100 mg/day, bisoprolol 10 mg/day), 3 weeks, −19.4% and −29.8% exercise duration, cardiac output unchanged, free-fatty-acid blunting.
"Selective β1-blockers are better tolerated for endurance" -> the drugs did not differ significantly; bisoprolol showed only a tendency to a smaller reduction.
Level B+ -> B per KB-LEVEL-RUBRIC (crossover, n=12). HR-zone advice labelled as the base's own practice.
Cross-references to duplicate stubs repointed to their canonical entries (REF-028->REF-072); the stubs were emptied on 2026-09-27.
2026-09-28: added Protocol from the abstract (Europe PMC/PubMed PMID 10678541).