Phase Relationship Between Skin Temperature and Sleep-Wake Rhythms in Women With Vascular Dysregulation and Controls Under Real-Life Conditions

Abstract

The aim of the study was to investigate whether women with primary vascular dysregulation (VD; main symptoms of thermal discomfort with cold extremities) and difficulties initiating sleep (DIS) exhibit a disturbed phase of entrainment (Ψ) under everyday life conditions. The authors predicted a phase delay of the distal-proximal skin temperature gradient and salivary melatonin rhythms with respect to the sleep-wake cycle in women with VD and DIS (WVD) compared to controls (CON), similar to that found in their previous constant-routine laboratory data. A total of 41 young healthy women, 20 with WVD and 21 matched CON without VD and normal sleep onset latency (SOL), were investigated under ambulatory conditions (following their habitual bedtimes) during 7 days of continuous recording of skin temperatures, sleep-wake cycles monitored by actimetry and sleep-wake diaries, and single evening saliva collections for determining the circadian marker of dim light melatonin onset (DLMO). Compared to CON, WVD showed increased distal vasoconstriction at midday and in the evening, as indicated by lower distal (DIST; hands and feet) and foot-calf skin temperatures, and distal-proximal skin temperature gradients (p< .05). WVD manifested distal vasoconstriction before lights-off that also lasted longer after lights-off than in CON. In parallel, WVD exhibited a longer SOL (p< .05). To define internal phase-relationships, cross-correlation analyses were performed using diurnal rhythms of wrist activity and foot skin temperature. WVD showed a phase delay in foot skin temperature (CON versus WVD: 3.57 ± 17.28 min versus 38.50 ± 16.65 min; p< .05) but not in wrist activity. This finding was validated by additional within-subject cross-correlation analyses using the diurnal wrist activity pattern as reference. DLMO and habitual sleep times did not differ between CON and WVD. The authors conclude that WVD exhibit a phase delay of distal vasodilatation with respect to their habitual sleep-wake cycle and other circadian phase markers, such as DLMO. A full factorial design will have to show whether the finding is specific to primary vascular dysregulation, to DIS, or to their interaction.

Daytime variation in ambient temperature affects skin temperatures and blood pressure: Ambulatory winter/summer comparison in healthy young women

“…1a) confirming previous findings [24,28]. Additionally, all STs exhibit a bimodal pattern during daytime with a maximum in the afternoon, which has been described in many other studies [19,20,29].…”

“…The diurnal amplitude was higher in distal than proximal skin regions and hence the T dist minus T prox gradient (data not shown) varies as well during the diurnal time course. The different diurnal amplitudes of T dist and T prox are mainly a consequence of different daytime and not night values, confirming previous studies [19,24,28]. Furthermore, these findings implicate increased blood redistribution from the core to the shell, which has been shown to be primarily induced by sleep [19,20].…”

“…All subjects were asked to maintain their normal daily activities and sleep wake schedules, however, without sporting activities and not taking a shower or a bath. • Not to experience thermal discomfort with cold extremities or not to be a control subject usually perceiving during winter according to [24].…”

Association Between Risk Factors and Glaucomatous Damage in Untreated Primary Open-angle Glaucoma

“…Finger skin temperature can be used as a measure of peripheral vasospasticity, as shown earlier. 16,17 Ocular pulse amplitude was obtained using Pascal Dynamic Contour Tonometer (Ziemer Ophthalmic Systems AG, Port, Switzerland), 18 and expressed in mm Hg as the difference between the systolic and the diastolic IOP.…”

Human Circadian Phase Estimation from Signals Collected in Ambulatory Conditions Using an Autoregressive Model

“…Through the exposure to different light levels during the night and day, a person becomes entrained to the external light/dark cycle (Wirz-Justice, 2007;Lack et al, 2007;Lewy and Sack, 1989). The master clock relays this timing information to the secondary clocks to synchronize the various organs and influence physiological and behavioral signals such as core body and skin temperature, heart rate, hormone levels, and the sleep/ wake cycle (Gompper et al, 2010;Van Someren and Nagtegaal, 2007;Jewett et al, 1999;Hofstra and de Weerd, 2008;Kronauer et al, 1999;St. Hilaire et al, 2007a;Levi, 2008).…”