Ahmet Turan Isik - Orthostatic Hypotension in Older Adults

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Orthostatic hypotension (OH) is defined as a certain amount of decrease in blood pressure in the first 3 min of transition from the supine position to the upright position. The prevalence, which increases with advancing age, varies between 20% and 30% in patients over 65 years of age. Besides, it is a medical problem resulting from the deterioration of the adaptation ability of the body with advancing age.

OH is associated with various adverse health outcomes, such as coronary heart disease, congestive heart failure, stroke, falls, dementia, and all-cause mortality. On the other hand, a range of comorbidities, which are common in older adults, and several medications may also play a role in the development of OH.

With multiple etiologies, OH is a significant cause of morbidity and mortality in the elderly. Therefore, it may be referred to as a geriatric syndrome that affects daily life activities and impairs quality of life. For this reason, in order not to overlook OH in the elderly, postural blood pressure changes should be evaluated routinely, as an essential part of the comprehensive geriatric assessment.

We decided to prepare the book Orthostatic Hypotension in Older Adults in order to examine OH in all aspects, which is such an important health problem for geriatric patients and to discuss the most rational approaches in this regard. It is our greatest happiness that the book will complement an important deficiency in geriatric practice.

We would like to thank all the scientists for their valuable contributions to the creation of the book by preparing the relevant chapters in the light of their knowledge and experience.

We wish that the book Orthostatic Hypotension in Older Adults will be beneficial to scientists and health professionals related to the subject.

Orthostatic tolerance is a term that defines the ability to prevent hypotension during gravity stress . [].

In the upright position due to the gravity, 500700 mL of blood translocates from the upper body to the lower limbs and splanchnic circulation and approximately 10% of the intravascular plasma shifts towards the extravascular space [].

Baroreceptor stimuli cause baroreflex (BR) . Baroreceptors are sensitive to pressure and strain and are located in the hearts auricles, heart fat pads, vena cava, aortic arch, and carotid sinus wall. As a result of baroreceptor stimulation, the parasympathetic nervous system is activated, while the sympathetic nervous system is inactivated []. After this short-term compensation, the muscle pump mechanism is activated to maintain blood pressure.

During upright position, skeletal muscles (especially lower extremity muscles) help to maintain venous return by compressing the veins, which is called a skeletal muscle pump mechanism. The muscle pump mechanism is very effective, so a single muscle contraction may direct more than 40% of the intramuscular blood volume to the venous return []. In the upright position, muscle pump mechanism after short-term cardiac compensation is the most important mechanism for the maintenance of BP.

When blood pressure drops below normal, decreased blood pressure directly affects the kidneys, increasing water and salt retention. A decrease in arterial pressure causes an increase in the secretion of aldosterone.