|Corbalan-Tutau, M. Dolores -|
|Madrid, Juan Antonio -|
|Ordovas, Jose M. -|
|Smith, Caren E. -|
|Nicolas, Francisco -|
|Garaulet, Maria -|
Submitted to: Society for Chronobiology International Conference Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 12, 2011
Publication Date: May 1, 2011
Citation: Corbalan-Tutau, M., Madrid, J., Ordovas, J., Smith, C., Nicolas, F., Garaulet, M. 2011. Differences in daily rhythms of wrist temperature between obese and normal-weight women: associations with metabolic syndrome features. Society for Chronobiology International Conference Proceedings. 28(5):425-433. Interpretive Summary: The physiology of people and other animals is regulated on a daily basis by what are referred to as “circadian” rhythms. These daily rhythms have been long-recognized for their influence on sleep and wake cycles, but evidence of their impact on other aspects of physiology, and on health and disease has been recently accumulating. We investigated the circadian rhythms of skin temperature, and their relationship to obesity. In two groups of women, 20 of normal body weight and 50 obese, we measured skin temperature every 10 minutes over a 3-day period. When we compared the temperature graphs in both groups of women, we detected differences in the patterns of the obese women compared to the normal weight women, in that the patterns of obese women were more “disrupted”. In addition, the rise in temperature that follows eating was different in obese and normal weight women. Moreover, these differences were related to greater risk of a pre-diabetes condition called metabolic syndrome, to hormones that are related to sleeping, such as melatonin, and to obesity-related proteins. Differences in circadian rhythms as reflected in skin temperature patterns may underlie a growing number of reported connections between sleep, eating and metabolic disease.
Technical 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 deg C +/- 0.3 deg 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.