Chronological aging in healthy subjects is associated with declines in muscle mass, strength, endurance, and aerobic fitness. Older individuals respond favorably to exercise, suggesting that physical inactivity plays an important role in age-related dysfunctions. Conversely, physical activity and improved exercise capacity is associated with lower mortality risk in hypertensive individuals. However, the impact of increased exercise capacity in older hypertensive individuals has not been investigated extensively.Design and Method:
A total of 2,401 hypertensive men, age ≥70 years of age (mean age 75 ± 4) from Washington DC and Palo Alto Veterans Affairs Medical Centers underwent routine exercise tolerance testing. Peak workload was estimated in metabolic equivalents (METs). Five fitness categories were established based on quintiles of peak METs achieved, adjusted for age: Least-Fit: 3.0 ± 0.6 METs (≤20%; n = 406); Low-Fit: 4.5 ± 0.3 METs (21%–40%; n = 586); Moderate-Fit: 5.4 ± 0.34 METs (41%-60%; n = 524); Fit: 6.7 ± 0.4 METs (61%–80%; n = 469) and High-Fit: 9.0 ± 1.6 METs (>80%; n = 396). All-cause mortality is reported with a mean follow-up period of 10.3 ± 6.2 (median 10.0). Cox proportional hazard models were applied after adjusting for age, BMI, race, CV disease, CV medications, and risk factors. P-values <0.05 using two sided tests were considered statistically significant.Results:
There were a total of 1,368 deaths (57.0%) or 55.3 deaths per 1000 person-years of follow-up. The association between mortality risk and fitness was inverse and graded. For every 1-MET increase in exercise capacity, the mortality risk was lowered by 10% (HR = 0.90; CI: 0.87–0. 92; p < 0.001). When compared to the individuals in the Least-Fit category, mortality risk was progressively lower ranging from 15% (HR = 0.85; CI: 0.72–0.99; p = 0.03) for the next fitness category (Low-Fit) to 47% those in the highest fitness category (HR = 0.53; CI: 0.44–0.64; p < 0.001).Conclusions:
Aerobic capacity is associated with lower mortality risk in hypertensive individuals ≥70 years of age.