The autonomic pathways mediating the bradycardia response to facial immersion (FI) have not been fully elaborated in man. By means of parasympathetic and sympathetic blockade we studied the heart rate response to FI in nine highly trained young swimmers, at rest and during dynamic cycle exercise. With no blockade, heart rate at rest declined with FI 36 +/- 18%. Under beta-blockade with propranolol or alpha-blockade with phentolamine FI produced a similar decrement. Atropine reduced the response. During exercise FI produced 48 +/- 9% decline without blockade. The response was similar with beta-blockade, but was completely abolished with atropine. Systolic blood pressure responses to FI measured by cuff in three subjects were small and bore no relation to the heart rate response. The results are compatible with parasympathetic efferent mediation of the heart rate response to FI. They are incompatible with a role for sympathetic mediation except as a complex interaction between parasympathetic and sympathetic influences. Hypertension and other sympathetic responses to FI do not play a role in production of bradycardia, but are apparently incidental effects. The heart rate decrement produced by FI increases with greater steady-state heart rate.

Williams's syndrome is characterised by unusual facies, abnormal growth and development, and variable cardiovascular anomalies. The most common of these are supravalvar aortic stenosis and peripheral pulmonary artery stenosis; but other lesions have been described, including pulmonary valve stenosis, septal defects, and peripheral systemic arterial stenosis.1Studies of the natural course of these cardiovascular anomalies are limited.2`We report the results of serial cardiac catheterisation in ten patients with Williams's syndrome who had supravalvar aortic stenosis or peripheral pulmonary artery stenosis or both. Patients and methodsThe ten patients were referred to and followed at the Izaak Walton Killam Children's Hospital in Halifax, Nova Scotia. These were all of the patients in whom

Originally a remembrance of an elderly physiologist, this paper illustrates the need for a standardized specification of certain experimental or survey conditions beyond those usually necessarily disclosed in conventional publications, namely calendar-dates, clock-times and geographic locations, to allow reference to helio-ionosphero-geomagnetics along with natural and artificial lighting and temperature. When possible, body times given by a marker rhythm also should be specified. A personalized chronobiologic cybercare can eventually include focus on infradians, beyond circadians. Benefits from longitudinal monitoring are: 1. Chronobiologically-interpreted blood pressure (BP) and heart rate (HR) monitoring enables the diagnosis and treatment of vascular variability anomalies (VVAs) or, if lasting in several 7-day records, disorders (VVDs), not yet screened for in practice, that increase cardiovascular disease risk independently of an elevated BP. 2. The optimal treatment time for the individual patient can be determined and potential harm avoided, since the same dose of the same medication for the same patient can help or harm depending only on when it is administered. 3. Benefit may be derived in cancer treatment timed according to marker rhythmometry. 4. The change from a spotcheck-based health care to one of internet-aided systematic self-surveillance by the automatic collection and analysis of time series stems from evidence that nonphotic and photic environmental influences affect biota, associations that may depend on geographic and temporal location. 5. Imaging in time includes formatting for time, globally and locally, for the mapping of a transdisciplinary spectrum of cycles involving "good" and "bad" strain in human physiology,versus sudden cardiac death, suicide and terrorism, all latter requiring rational countermeasures.

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