Background: Physical activity is associated with low mortality in men, but little is known about the association in women, different age groups, and everyday activity.

Objective: To compare risk of myocardial infarction associated with smoking in men and women, taking into consideration differences in smoking behaviour and a number of potential confounding variables. Design: Prospective cohort study with follow up of myocardial infarction. Setting: Pooled data from three population studies conducted in Copenhagen. Subjects: 11 472 women and 13 191 men followed for a mean of 12.3 years. Main outcome measures: First admission to hospital or death caused by myocardial infarction. Results: 1251 men and 512 women had a myocardial infarction during follow up. Compared with non-smokers, female current smokers had a relative risk of myocardial infarction of 2.24 (range 1.85-2.71) and male smokers 1.43 (1.26-1.62); ratio 1.57 (1.25-1.97). Relative risk of myocardial infarction increased with tobacco consumption in both men and women and was higher in inhalers than in non-inhalers. The risks associated with smoking, measured by both current and accumulated tobacco exposure, were consistently higher in women than in men and did not depend on age. This sex difference was not affected by adjustment for arterial blood pressure, total and high density lipoprotein cholesterol concentrations, triglyceride concentrations, diabetes, body mass index, height, alcohol intake, physical activity, and level of education. Conclusion: Women may be more sensitive than men to some of the harmful effects of smoking. Interactions between components of smoke and hormonal factors that may be involved in development of ischaemic heart disease should be examined further.

Increased heart rate and reduced heart-rate variability are associated with subclinical inflammation in healthy middle-aged and elderly subjects. The increased mortality that has been reported in these settings may thus have a common aetiology. An autonomic imbalance in favour of the sympathetic system may interact with inflammatory processes to play a more important role in the process of atherosclerosis than previously thought.

ObjectiveTo examine whether elevated resting heart rate (RHR) is an independent risk factor for mortality or a mere marker of physical fitness (VO2Max).MethodsThis was a prospective cohort study: the Copenhagen Male Study, a longitudinal study of healthy middle-aged employed men. Subjects with sinus rhythm and without known cardiovascular disease or diabetes were included. RHR was assessed from a resting ECG at study visit in 1985–1986. VO2Max was determined by the Åstrand bicycle ergometer test in 1970–1971. Subjects were classified into categories according to level of RHR. Associations with mortality were studied in multivariate Cox models adjusted for physical fitness, leisure-time physical activity and conventional cardiovascular risk factors.Results2798 subjects were followed for 16 years. 1082 deaths occurred. RHR was inversely related to physical fitness (p<0.001). Overall, increasing RHR was highly associated with mortality in a graded manner after adjusting for physical fitness, leisure-time physical activity and other cardiovascular risk factors. Compared to men with RHR ≤50, those with RHR >90 had an HR (95% CI) of 3.06 (1.97 to 4.75). With RHR as a continuous variable, risk of mortality increased with 16% (10–22) per 10 beats per minute (bpm). There was a borderline interaction with smoking (p=0.07); risk per 10 bpm increase in RHR was 20% (12–27) in smokers, and 14% (4–24) in non-smokers.ConclusionsElevated RHR is a risk factor for mortality independent of physical fitness, leisure-time physical activity and other major cardiovascular risk factors.