Differences in Daily Rhythms of Wrist Temperature Between Obese and Normal-Weight Women: Associations With Metabolic Syndrome Features

Abstract

The circadian rhythm of core body temperature is associated with widespread physiological effects. However, studies with other more practical temperature measures, such as wrist (WT) and proximal temperatures, are still scarce. The aim of this study was to investigate whether obesity is associated with differences in mean WT values or in its daily rhythmicity patterns. Daily patterns of cortisol, melatonin, and different metabolic syndrome (MetS) features were also analyzed in an attempt to clarify the potential association between chronodisruption and MetS. The study was conducted on 20 normal-weight women (age: 38 ± 11 yrs and BMI: 22 ± 2.6 kg/m2) and 50 obese women (age: 42 ± 10 yrs and BMI: 33.5 ± 3.2 kg/m2) (mean ± SEM). Skin temperature was measured over a 3-day period every 10 min with the “Thermochron iButton.” Rhythmic parameters were obtained using an integrated package for time-series analysis, “Circadianware.” Obese women displayed significantly lower mean WT (34.1°C ± 0.3°C) with a more flattened 24-h pattern, a lower-quality rhythm, and a higher intraday variability (IV). Particularly interesting were the marked differences between obese and normal-weight women in the secondary WT peak in the postprandial period (second-harmonic power [P2]), considered as a marker of chronodisruption and of metabolic alterations. WT rhythmicity characteristics were related to MetS features, obesity-related proteins, and circadian markers, such as melatonin. In summary, obese women displayed a lower-quality WT daily rhythm with a more flattened pattern (particularly in the postprandial period) and increased IV, which suggests a greater fragmentation of the rest/activity rhythm compared to normal-weight women. These 24-h changes were associated with higher MetS risk.

Circadian rhythms, food timing and obesity

“…The results of this study showed that these lean women, after 1 week of eating late, suffered from metabolic alterations that usually characterise obese women, such as decreased glucose tolerance, decreased resting energy expenditure and decreased carbohydrate oxidation. Moreover, late eaters had a flattened pattern of daily cortisol and alterations in daily rhythms of body temperature similar to those that characterise obese women as previously described (39) . In Table 3, we summarise the specific recommendations for the prevention of obesity and MetS by improving the circadian system health, based on available scientific evidence proved in epidemiological, clinical and experimental animals (A); on interventional studies in human subjects or in animal models (B); and on preliminary studies or low number of studies (C).…”

Circadian rhythmicity as a predictor of weight-loss effectiveness

“…29 Moreover, our group has previously demonstrated that the increase in the rhythm fragmentation with obesity is related to a decrease in melatonin amplitude, which has been described as a biological sign of chronodisruption. 26 It is important to highlight the fact that in the current work, significant differences were found in IV between high responders and low responders, whereas no significant differences were found in the IS, which suggests that these differences in wristtemperature variables were not because of phase instability.…”

“…25 Interestingly, among the differences in circadian parameters, the reduced amplitude found in low responders is one of the hallmarks of aging. An attenuated amplitude has been observed in elderly subjects as well as in the obese 26 and in Alzheimer's patients. 24,27 A healthy wrist-temperature pattern that characterizes ideal body-weight individuals shows wide amplitude with high-temperature values during sleep time and a pronounced drop after arising in the morning with low values during wake time.…”

“…8,9 This is also supported by the fact that obese individuals appear to be less responsive to environmental cues and diurnal variations in body temperature are diminished in obese humans. 10 On the other hand, it has been proposed that an alteration in the body-temperature pattern early in life may predict further obesity in dogs. 11 Therefore, it can be hypothesized that the circadian system could be implicated in the effectiveness of weight-loss interventions.…”

High-fat diet and glucose and albumin circadian rhythms’ chronodisruption in rats

“…The lifestyle of any person is a well-defined rhythmic phenomenon and it is controlled by the circadian system (Corbalán-Tutau et al, 2011). This system coordinates living organisms with their changing environments and allows them to perform those biochemical, physiological, or behavioral functions that ensure the survival of all species at the proper times.…”