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Background Physical fitness has been shown to predict cardiovascular death during long-term follow-up. In the present study we aimed to investigate how physical fitness and other cardiovascular risk factors at middle-age influenced the risk of cardiovascular death during the early (0–11 years), intermediate (12–23 years) and late (24–35 years) parts of a 35-year observation period. Methods and results Age-adjusted physical fitness was calculated in 2014 apparently healthy, middle-aged men after maximal bicycle electrocardiogram-tests in 1972–1975 (Survey 1) and 1979–1982 (Survey 2). The men were assessed through 35 years after Survey 1, and 28 years after Survey 2 by Cox proportional hazards models. Low Survey 1 physical fitness was independently associated with increased risks of early and intermediate, but not late, cardiovascular death. Survey 1 to Survey 2 change in physical fitness, age, smoking status, systolic blood pressure and cholesterol impacted cardiovascular death risks in all periods. Family history of coronary heart disease impacted early and intermediate, but not late, cardiovascular death. Conclusions Most classical cardiovascular risk factors were strong predictors of early, intermediate and late cardiovascular death. Physical fitness measured at median age 50 years was independently associated with risk of early cardiovascular death, but the association weakened as time progressed. Change in physical fitness during middle-age impacted cardiovascular death risk in a full lifetime perspective. Thus, our data suggest that physical fitness is a modifiable cardiovascular risk factor with limited duration in contrast to the sustained impact of smoking, blood pressure and cholesterol on cardiovascular mortality.

Heart rate reserve (HRR) has been reported to be inversely associated with cardiovascular (CV) disease and death. The impact of physical fitness (PF) on this relationship has not, however, been described in detail. We investigated how different levels of PF influenced the association between HRR and CV death during a 35-year follow-up.HRR and PF were measured in 2014 apparently healthy, middle-aged men during a symptom-limited bicycle exercise test in 1972-75. The men were divided into tertiles (T1-T3) by age-adjusted HRR. Morbidity and mortality data were registered from hospital charts through 2007 and the Norwegian Cause of Death Registry. Adjusted Cox proportional hazard regression models were used to calculate risks. Incidence of CV death was 528 (26%) during median 30 years of follow-up. Men with the lowest HRR had 41% (HR 1.41 [1.14-1.75]) increased risk of CV death compared with the men with the highest. We found a significant interaction between age-adjusted PF and HRR. After stratifying the men by PF, results were statistically significant only among men with the lowest PF, where the men with lowest HRR had a 70% (HR 1.70 [1.12-2.67]) increased risk of CV death compared with the men with the highest.Low HRR was independently associated with increased risk of CV death in apparently healthy, middle-aged men. The predictive impact of HRR on CV death risk was, however, confined to unfit men.

The prognostic value of an isolated J-point depression, or rapidly upsloping ST-segment, on an exercise ECG has long been assumed to be a benign variant. However, little or no data supporting this assumption may be found in the literature. Our task was to examine if a rapidly upsloping ST-segment on an exercise ECG is associated with changes in risk of dying from CHD in 2014 healthy middle-aged men followed for 35 years.A group of healthy middle-aged men (n = 2014) participated in a cardiovascular survey. They underwent an examination programme including a symptom-limited ECG bicycle exercise test. Exercise induced ST-segments were categorised in three groups: normal ST-segment (n = 1383), rapidly upsloping (n = 401), and ST-depression (n = 230). Survival analyses were adjusted for smoking status, total cholesterol, systolic blood pressure, maximal heart rate, and physical fitness. The mean follow-up time was 35 years.The rapidly upsloping group had a 30% decreased risk of CHD death (hazard ratio, HR, 0.70, 95% CI 0.51-0.95) compared to the normal ST-segment group. The risk of CVD-death was numerically lower in the rapidly upsloping group (HR 0.82, 95% CI 0.65-1.04) compared to the normal ST-segment group. The ST-depression group had a 1.45-fold (HR 1.45, 95% CI 1.09-1.90) increased risk of CHD death compared to the normal ST-segment group.The rapidly upsloping ST-segment was a common finding (20%) on exercise ECG among healthy middle-aged men and was associated with a 30% reduced risk of dying from CHD compared to individuals with normal ST-segment. A rapidly upsloping ST-segment on exercise ECG may represent the true healthy state.