Arterial Blood Pressure and Lifestyle Variability: In Quest of a Comprehensive Approach

The role of blood pressure variability (BPV) in the development of symptoms and target organs disease is a lasting object of investigations.1,2 These were primarily triggered by the subjective reports of patients, a step usually not quoted specifically; subsequently, pioneering clinical observations3 were carried out, supported also by animal models research,4 but the effects of drugs on BPV5 and on clinical outcome and epidemiological studies6 are still the core of our present knowledge. BPV is approached as a clue distinct from and inclusive of the fluctuations related to the circadian rhythm, namely the day–night changes.7 However, the separate effects of physical exercise, sleep, digestive and other body functions, mood and emotional reactions are not fully detected, thus missing clues potentially useful for personalized intervention. Handy and friendly reference measurement, with an adequate timing of recording suitable for the purpose of guiding diagnosis for better targeting and monitoring interventions, is still a requirement that is not sufficiently satisfied. Spontaneous oscillations are observed both over short-term (minutes to days) and long-term (month) periods, and these different features are not adequately merged in current methodologies for assessing BPV. Therefore, the search for a shared, meaningful, and comprehensive clinical paradigm for the detection of BPV in individual subjects is still a challenge for clinicians and epidemiologists. The reliability of the model chosen for the definition of BPV itself does not take into sufficient consideration the possible relevance of the rate of variation (peak rate of increase or decrease of BP).8 Changes in BP may be very quick or quite slow, with possible different acute and chronic effects: this topic is currently scarcely investigated in BPV. Other methodological aspects, apart from the features of the measuring instrument, should be considered: Is systolic or diastolic BPV more informative? Does mean arterial BPV provide better, overlapping, and/or incremental information? Should BPV be weighted by concurrent Systolic BP, Diastolic BP, Mean Arterial BP, or heart rate? Do postural changes in BPV provide important prognostic information? A greater challenge is the search for and the definition of putative contributing factors of BPV, if any, which may be mechanisms of BPV itself but, also, of the target organ involvement. In this case, the route should be quite easy to plan, but seemingly still difficult to travel. The following areas should be considered in meaningful approaches to better understanding BPV: Conventional, validated indexes of old fashioned and novel robust risk factors of cardiovascular disease (CVD),9,10 such as body weight (not only obesity), serological biomarkers related to CVD and arterial hypertension (lipids, uric acid, glucose, creatinine, homocysteine, others), electrocardiogram; The impact of diet and lifestyle exposures (nutrition, physical activity, sleep, smoking, alcohol, coffee, and salt intake);11 Social and environmental determinants of health;12 Familial disposition to CVD and arterial hypertension, as a proxy of genetic information.13 The approach chosen by Maseli et al.14 is a significant methodological advancement over the available publications dealing with a more comprehensive definition and interpretation of BPV and of its putative contributing factors. In this sense, it is not focused on the consequences of BPV, but on the associated conditions that may be influential on BPV. Their model includes several valuable points: (i) the definition of BPV, systolic and diastolic, normalized by the levels of BP; (ii) the separate assessment of day and night BP and of systolic and diastolic BPV; (iii) the use of an automatic 24-hour recording tool with the analysis of an adequately great number of measurements; (iv) the reference to a validated score of lifestyle profile, and, separately, to its components; and (v) the use of an explicitly suited statistical analysis of data. The limitations of the information provided14 are many, but such information is able to elicit novel ideas and line of research. The inclusion of healthy subjects, investigating a population aged 25 to 41 years, is certainly useful for better defining associations, if any, of lifestyle features with BPV excluding disease confounding effects. Nonetheless, available studies address association of a greater BPV to disease, more in hypertensive than in normotensive subjects, which show an increased mortality in follow-up studies,6 skipping healthy subjects, and, equally important, younger if not pediatric subjects. Moreover, the reference studies on BPV describe and monitor visit-to-visit and day-to-day BPV, i.e., encompassing longer periods of variability and not single day measurements.14 Since these studies have provided the evidentiary link between BPV and CVD risk, the investigation of the lifestyle–BPV relationship must also be examined in studies utilizing day-to-day BPV. The lifestyle score15 may not sufficiently mirror and summarize the single components of the “profile”. Epidemiological, and therefore intervention advice for effectively managing lifestyle profile toward healthier behaviors remain a goal that is far from being reached. This limitation is clearly acknowledged in the conclusion by Maseli et al.,14 and the suggestions for any type of intervention remain excessively indistinct, if not generic. Actually, in previous studies,16 the Mediterranean Diet, which may be considered a proxy of an healthy diet pattern,17 was found to be favorably associated with lower BPV.16 As in other fields of clinical research, top-down and bottom-up are both rewarding strategies of information processing and knowledge ordering, aims that can be itemized into 3 main lines of research: Detection of the epidemiological relevance of BPV, after definition and optimization of criteria agreed on by the medical community; Investigations suitable to explain outcomes of the factors associated with BPV, encompassing the most credited risk factor indexes and the behavioral and social determinants of health; Sufficiently large and lasting intervention studies. Even if limited information is currently available, the effects on BPV of strategies modifying critical features of lifestyle may be already available, or ongoing, so that comprehensive and meaningful novel information and indication should be available. Throughout the world, patients monitored for BP control are many: assessment and monitoring of some critical components of lifestyle, and namely dietary and physical exercise profiles, work and sleep patterns, alcohol, salt, smoking, and coffee habits may be performed. This topic is particularly critical when facing adolescent or juvenile essential hypertension,18,19 since such subset deserves often a nonpharmacological approach and proactive lifestyle-change interventions. The relationship with the core questions, “What is the threshold at which antihypertensive treatment should be initiated?” and “What target blood pressure should we strive for to achieve maximum benefit in patients with hypertension?”20 is evident because BPV is a limitation of a definite threshold of normal BP. Differently, if a reliable definition of BPV is available, in any age but especially in young persons, its abnormality may become an appropriate caveat and a further target for the prescription of personalized and lasting intervention. The renewed interest in lifestyle changes for the management of possible causes of arterial hypertension with its focus on BPV is the merit of the study of Maseli et al.,14 which confirms the interest and sensibility of the community of physicians involved in the understanding, prevention, and treatment of arterial hypertension. The author declared no conflict of interest.