Measuring mental strain by duration of blood pressure overswing (CHAT): Case report

Among innumerable others, we had earlier reported elevations of blood pressure (BP) associated with physical as compared to mental tasks. The latter happened to be associated with higher BP values than the former. At variance with others, we assess the variations against the background of monitoring BP, around the clock along the scales of decades, to detect Vascular Variability Anomalies (VVAs), lasting only for a few days. In addition to a lasting BP elevation, we here focus upon a more sensitive index of mental strain, the duration of a BP overswing during 24 hours (h) (CHAT, short for Circadian Hyper-Amplitude- Tension), as a major objective quantitative measure of concern, called strain rather than stress. We do this to separate the approach we use by accounting for, if not by assessing a spectrum of rhythms -- circadian, about 3.5- and 7-day, and other infradians -- from any stress research that is currently based, at best, on (imaginary) baselines and ignores the difficulties associated with so doing. CHATduration, in a 24-h record, assesses the loads or challenges posed by daily life and/or the ability to cope with them. It complements short-term large BP elevations, that can be transients in a long record, and usually precedes the elevations of the Midline-Estimating Statistic Of Rhythm (MESOR, M) and of the hyperbaric index (area of excess) computed from stacked data. We have also found that the 1- day (or a few-day; transient) CHAT can be a physiological response in VVA. The week-long and longer CHAT may be detected when, in the same record, there is no abnormality in BP-M derived by curve-fitting or in the stacking-derived hyperbaric index. Mental loads, such as concern about a relatively impromptu symposium organized for a birthday (not planned with the usual lead time of a year or longer and without the seemingly offered, but never granted, support by a government agency), was associated with sequences of up to 6 consecutive weekly BP overswings (weekly, actually longer CHAT). Certain short-term events, with some responsibility, lasting only a few hours, such as hosting a social gathering (dinner party), depending on the loads involved, can, but must not, be associated with occurrences of 1- or a few-day (transient) CHAT. The absence for 14 days of any situational weekly or shorter CHAT in the around-the-clock record quantifies a transient respite, which as we show for a nonagenarian (FH) must not lull into a sense of false security: after 2 weeks of fully absent CHAT, mostly 1-day CHAT recurred, not by participating at a party but in association with hosting a social gathering. CHAT also recurred during visits by welcome colleagues. There is no substitute for long-term monitoring of BP once the diagnosis of a Vascular Variability Disorder (VVD) has been made, whether for strain management, for elevated disease risk detection or for validating the effectiveness of treatment. Even if, in samples of millions, mortality peaks on Christmas and New Year's Day, mortality on these holidays is at a local minimum in a sample of thousands in Minnesota. An elevation of mortality from myocardial infarction during the holiday season notwithstanding, we find that the same person may respond differently to holidays at different times and under different conditions. What counts for the individual, one can measure the response by Chronobiologically-interpreted (C) Ambulatory (A) BP Monitoring (C-ABPM) and act accordingly. Managing strain is important for health outcomes by a comparison of an ongoing within-day and day-to-day record of events and activities with both a daily and a weekly chronobiologic analysis, which offers a detailed quantitative perspective of loads and their effects and meets the need for a personalized approach to one's lifestyle. Data on 7-day records of 27 individuals -- the senior author (FH) and 26 participants in Tosa City, Kochi, Japan, in the BIOCOS project on The BIOsphere and the COSmos -- as well as other data from various settings, are here analyzed for VVD.