The prevalence of heat-related cardiorespiratory symptoms among vulnerable groups is not well known. We therefore estimated the prevalence of heat-related cardiorespiratory symptoms among the Finnish population and their associations with social and individual vulnerability factors. The data came from the National FINRISK 2007 Study, in which 4007 men and women aged 25–74 answered questions on heat-related cardiorespiratory symptoms in the Oulu Cold and Heat Questionnaire 2007. Logistic regression was used to calculate odds ratios (ORs), their 95% confidence intervals (CIs), and model-predicted prevalence figures. The prevalence of heat-related cardiorespiratory symptoms was 12%. It increased with age, from 3% at the age of 25 years to 28% at the age of 75 years. The symptoms were associated with pre-existing lung (OR 3.93; CI 3.01–5.13) and cardiovascular diseases (OR 2.27; 1.78–2.89); being a pensioner (OR 2.91; 1.65–5.28), unemployed (OR 2.82; 1.47–5.48), or working in agriculture (OR 2.27; 1.14–4.46) compared with working in industry; having only basic vs academic education (OR 1.98; 1.31–3.05); being female (OR 1.94; 1.51–2.50); being heavy vs light alcohol consumer (OR 1.89; 1.02–3.32); undertaking hard vs light physical work (OR 1.48;1.06–2.07); and being inactive vs active in leisure time (OR 1.97; 1.39–2.81). The adjusted prevalence of symptoms showed a wide range of variation, from 3 to 61% depending on sex, age, professional field, education, and pre-existing lung and cardiovascular diseases. In conclusion, heat-related cardiorespiratory symptoms are commonly perceived among people with pre-existing lung or cardiovascular disease, agricultural workers, unemployed, pensioners, and people having only basic education. This information is needed for any planning and targeting measures to reduce the burden of summer heat.
