Nocturia significantly impairs quality of life, especially in the elderly population, and urinary retention is a main target of treatment for urologists. In addition to nocturia, cardiovascular diseases are common in the elderly population, and a systematic review showed that hypertension and heart failure are often associated with nocturia. One possible pathogenic mechanism underlying the development of hypertension is an increase in blood pressure due to excessive salt intake in people with high-salt sensitivity. From Guyton's natriuretic curve, we can infer that salt-sensitive hypertensive patients who consume too much salt do not excrete salt during the daytime and are forced to excrete salt at night, resulting in increased urine production and nocturia. In patients with heart failure, the nocturnal supine position leads to an increase in central fluid volume due to an increase in venous return from the periphery, and the secretion of natriuretic peptide is stimulated by the stretching of the atria and ventricles. Thus, natriuresis due to hypertension and hydrodiuresis due to heart failure may cause nocturia, which can effectively be treated by the administration of thiazide diuretics and loop diuretics in the morning, respectively. Because cardiovascular diseases, such as hypertension and heart failure, can cause nocturia and because the treatment methods differ depending on the cause, it is necessary to pay close attention to nocturia in the management of lifestyle-related diseases, such as cardiovascular disease. Thus, natriuresis due to hypertension and hydrodiuresis due to heart failure may cause nocturia, which can effectively be treated by the administration of thiazide diuretics and loop diuretics in the morning, respectively. Because cardiovascular diseases, such as hypertension and heart failure, can cause nocturia and because the treatment methods differ depending on the cause, it is necessary to pay close attention to nocturia in the management of lifestyle-related diseases, such as cardiovascular disease. Hypertension was significantly associated with nocturia in both men and women, and approximately twice as many individuals in the group with nocturia had hypertension than in the group without nocturia [ 6 ]. In 2020, an additional systematic review and meta-analysis reported that hypertension was associated with a 1.2- to 1.3-fold higher risk of nocturia based on 25 articles that met the criteria for inclusion [ 7 ]. A cross-sectional study of 8284 people aged ≥40 years in the general population showed that hypertension was associated with a two-fold higher risk of urination during sleep in women but not in men [ 8 ]. [ 23 ] In a clinical study, patients with salt-sensitive hypertension who consumed a high-salt diet (12–15 g/day) for a week had an extremely large increase in their nocturnal blood pressure compared to those on a low-salt diet (1–3 g/day) [ 30 ]. When patients with chronic kidney disease, who are representative of the population with salt-sensitive hypertension due to impaired salt excretion, underwent 24-h ambulatory blood pressure monitoring, most were found to have nondipping early morning hypertension and nocturnal hypertension [ 31 ]. When thiazide diuretics were taken in the morning, patients with dipping early morning hypertension and no nocturnal hypertension did not experience a significant reduction in their daytime or nighttime blood pressure values, whereas the those with dipping early morning hypertension and nocturnal hypertension had a stronger antihypertensive effect at night, when thiazide diuretics were considered to be ineffective [ 32 ]. This may be because thiazide diuretics result in the excretion of sodium during the daytime, obviating the need for nocturnal sodium excretion, which explains the lack of increase in blood pressure. Although loop diuretics are often used as a treatment for nocturia, they are not effective in patients with salt-sensitive hypertension because loop diuretics are mainly water diuretics rather than natriuretics, and sufficient sodium excretion cannot be achieved with loop diuretics. Thiazide diuretics, rather than loop diuretics, should be considered for the treatment of nocturia in patients with nocturnal hypertension rather than early morning hypertension due to aging, renal dysfunction (excretion disorders), obesity, diabetes mellitus, postmenopausal status, or genetics (hypersodium reabsorption). One report prospectively analyzed the clinical data from 452 consecutive patients with acute dyspnea in the emergency department, and 217 patients with dyspnea due to acute heart failure had an elevated risk of nocturia (OR 2.4; 95% CI 1.6–3.7) [ 34 ]. In a cross-sectional study of 173 patients with chronic heart failure, 87 patients urinated 1–2 times during the night, and 56 patients urinated 3 or more times during the night, resulting in sleep disturbances [ 35 ]. However, when venous return from the periphery increases due to being in a supine position at night, this adaptation fails, and excessive blood flow to the center (central shift) causes orthopnea [ 38 ]. Atrial and ventricular stress increased by that central shift leads to the production of members of the natriuretic peptide family, such as ANP and BNP, and nocturnal urine production is increased. As shown in Fig. 2 , diuresis in heart failure patients is considered an adaptive phenomenon to prevent clinical deterioration. First, we should evaluate urinary retention and voiding disorders to diagnose BPH or OAB based on the International Prostate Symptom Score. Furthermore, natriuresis and water diuresis are the main mechanisms underlying increased nocturia in patients with hypertension and heart failure, respectively, and thiazide antihypertensive diuretics and loop diuretics are the appropriate therapeutic agents (Fig. 3 ). However, coronary artery disease is not a direct risk factor for nocturia but rather the result of a common cause,