An abnormal blood pressure (BP) response to exercise is an important physiological variable associated with a risk of sub-clinical hypertension. Reference values are poorly defined and lack contextualization to physiological demands that can be obtained among very active populations.
PURPOSE: To assess the relationship between systolic BP (SBP) and workload and to determine reference values of SBP response to exercise in endurance athletes.
METHODS: We recruited 123 current and former endurance athletes (76% male), aged 16-80 years. BP was measured every 2 min during a maximal bicycle cardiopulmonary exercise test using a TangoM2 automated BP monitor. Relationship between SBP measured at 25%, 50%, 75% and 100% of maximum workload and power output during exercise were determined by linear regression analysis using STATA software.
RESULTS: SBP increased from 128 ±13 mmHg in males (age 40±18 years) and 116 ± 12 mmHg in females (age 35±14 years) to peak 223 ± 27 mmHg and 203 ± 19 mmHg, respectively (P<0.0001). The majority of participants demonstrated an exaggerated SBP response to exercise (72% of males and 82% of females) as defined by the American Heart Association guidelines. There was a strong correlation between power output and SBP (r² = 0.67, P<0.001, Figure 1). Males achieved 123±18% and females 134±26% of their predicted VO2 max (P<0.01). There was no statistical difference in exercise SBP response according to age or BMI. Gender and hypertensive medication did have a statistically significant, but weak correlation to SBP (P<0.01 and P<0.001 respectively r² =0.03 for both)
CONCLUSION: High SBP values are observed in athletes at peak exercise, frequently exceeding ‘normal value’ definitions. However, SBP increases can be explained by the supra-normal exercise capacity, thus, should be considered in the context of exercise capacity.