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Relation of cardiac output at rest and during exercise to age in essential hypertension
1Department of Pathophysiology, Faculty of Medicine, University of Leuven, Belgium.
Insights
Cardiac output declines with age in men with essential hypertension, irrespective of cardiovascular disease. This age-related decrease in cardiac function is independent of weight and blood pressure, suggesting other factors are at play.
Area of Science:
- Cardiovascular Physiology
- Gerontology
- Hypertension Research
Background:
- Cardiac output (CO) is known to decrease with age.
- This decline has been attributed to an increased prevalence of occult cardiovascular disease.
- Essential hypertension is a common condition affecting cardiovascular health.
Purpose of the Study:
- To investigate the relationship between cardiac output and age in men with essential hypertension.
- To determine if occult cardiovascular disease explains the age-related decline in cardiac output.
- To analyze hemodynamic parameters across different age groups and activity levels.
Main Methods:
- Analysis of cardiac output using the direct oxygen Fick method in 110 men aged 16-64.
- Participants had World Health Organization stage I or II essential hypertension and were followed for 7 years.
- Hemodynamic measurements were taken at rest (supine and seated) and during upright bicycle exercise.
Main Results:
- Cardiac output showed a significant inverse relationship with age (p < 0.01) at rest and during exercise.
- This inverse relationship was independent of body weight and mean intra-arterial pressure.
- Stroke volume decreased with age in the supine position, while heart rate decreased with age during upright rest and exercise.
Conclusions:
- In essential hypertensive men free of cardiovascular complications, cardiac output declines with age independently of activity level.
- Occult cardiovascular disease does not appear to be the primary driver of age-related cardiac output decline in this cohort.
- Findings suggest intrinsic aging processes or other non-disease-related factors influence cardiac output reduction over time.
Abstract:
It has been suggested that the decline of cardiac output with age is due to increased prevalence of disease, particularly occult coronary artery disease. Therefore, the relation of cardiac output (direct oxygen Fick method) to age was analyzed in 110 sixteen- to 64-year-old men with World Health Organization stage I or II essential hypertension at the time of the hemodynamic study, who were alive and free of cardiovascular complications 7 years later. At supine and seated rest, during upright bicycle exercise at 50 W and and at peak work load, cardiac output was inversely (p less than 0.01) related to age. These relations were independent of weight and mean intraarterial pressure. Stroke volume decreased with advancing age at supine rest, but not at rest and during exercise in the seated position. Heart rate was not affected by age in the supine position, but was slower in older patients during upright rest and at peak exercise. In conclusion, in patients with essential hypertension who remained free of cardiovascular complications for 7 years, cardiac output was independently and inversely related to age at various levels of activity. These findings suggest that occult cardiovascular disease does not explain the decline in cardiac output with age in patients with essential hypertension.