The early detection of subclinical myocardial dysfunction can contribute to the treatment and prevention of heart failure (HF). The aim of the study was to (i) describe myocardial global longitudinal strain (GLS) patterns in a large general population sample from Norway and their relation to established cardiovascular disease (CVD) risk factors; (ii) to determine its normal thresholds in healthy individuals and (iii) ascertain the relation of myocardial GLS to stage A subclinical heart failure (SAHF). Participants (n = 1855) of the 7th survey of the population-based Tromsø Study of Norway (2015-2016) with GLS measurements were studied. Linear and logistic regression models were used for assessment of the associations between CVD risk factors and GLS. Mean GLS (SD) in healthy participants was - 15.9 (2.7) % in men and - 17.8 (3.1) % in women. Among healthy subjects, defined as those without known cardiovascular diseases and comorbidities, GLS declined with age. An increase of systolic blood pressure (SBP) of 10 mm Hg was associated with a 0.2% GLS reduction. Myocardial GLS in individuals with SAHF was 1.2% lower than in participants without SAHF (p < 0.001). Mean myocardial GLS declines with age in both sexes, both in a general population and in the healthy subsample. SBP increase associated with GLS decline in women. Our findings indicate high sensitivity of GLS for early subclinical stages of HF.