Oczywiście, że się przystosuje i to bardzo szybko (zazwyczaj do 7 dni) a ja o tym wspomniałem. Przestawi swój zegar, i dla niego doba dalej będzie miała te 24h, chociaż już rytm okołodobowy nie będzie się zbiegał z dziennym. Gorzej, gdy codziennie będzie oszukiwany, codziennie będą różne zmiany, wtedy już nie będzie tak fajnie.
Poza tym jeżeli chodzi o zdrowie, to subiektywne odczucia nie zawsze idą w parze z rzeczywistością. Żeby być obiektywnym musiałbyś porównać np. dwa etapy: pracy "standardowej" i "na zmianę" oraz wykonane podczas nich badania, głównie hormonów, ciśnienia krwi, poziomu cukru, profilu lipidowego. Jest to oczywiście uciążliwe i kosztowne i nie każdy ma ochotę robić testy na sobie, na szczęście inni robią to za/dla nas
Było na prawdę dużo badań przeprowadzonych na pracownikach "nocnej zmiany". Dla przykładu te bardziej ogólne, choć są też dokładniejsze dotyczące wielu hormonów. Nie mam czasu na tłumaczenie wszystkiego, może w tygodniu urywki, teraz tylko jedno zdanie z pierwszego abstractu, które jest dla badaczy oczywiste, jest to wstęp:
Jest wiadome, że pracownicy zmianowi mają większe ryzyko rozwoju chorób sercowo-naczyniowych w porównaniu z pracownikami dziennymi.
1: Chronobiol Int. 2004;21(6):937-47. Links
Postprandial metabolic profiles following meals and snacks eaten during simulated night and day shift work.
* Al-Naimi S,
* Hampton SM,
* Richard P,
* Tzung C,
* Morgan LM.
School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, UK.
Shift workers are known to have an increased risk of developing cardiovascular disease (CVD) compared with day workers. An important factor contributing to this increased risk could be the increased incidence of postprandial metabolic risk factors for CVD among shift workers, as a consequence of the maladaptation of endogenous circadian rhythms to abrupt changes in shift times. We have previously shown that both simulated and real shift workers showed relatively impaired glucose and lipid tolerance if a single test meal was consumed between 00:00-02:00 h (night shift) compared with 12:00-14:00 h (day shift). The objective of the present study was to extend these observations to compare the cumulative metabolic effect of consecutive snacks/meals, as might normally be consumed throughout a period of night or day shift work. In a randomized crossover study, eight healthy nonobese men (20-33 yrs, BMI 20-25kg/m2) consumed a combination of two meals and a snack on two occasions following a standardized prestudy meal, simulating night and day shift working (total energy 2500 kcal: 40% fat, 50% carbohydrate, 10% protein). Meals were consumed at 01:00/ 13:00 h and 07:00/19:00h, and the snack at 04:00/16:00 h. Blood was taken after an overnight fast, and for 8 h following the first meal on each occasion, for the measurement of glucose, insulin, triacylglycerol (TAG), and nonesterified fatty acids (NEFA). RM-ANOVA (factors time and shift) showed a significant effect of shift for plasma TAG, with higher levels on simulated night compared to day shift (p < 0.05). There was a trend toward an effect of shift for plasma glucose, with higher plasma glucose at night (p = 0.08), and there was a time-shift interaction for plasma insulin levels (p < 0.01). NEFA levels were unaffected by shift. Inspection of the area under the plasma response curve (AUC) following each meal and snack revealed that the differences in lipid tolerance occurred throughout the study, with greatest differences occurring following the mid-shift snack. In contrast, glucose tolerance was relatively impaired following the first night-time meal, with no differences observed following the second meal. Plasma insulin levels were significantly lower following the first meal (p < 0.05), but significantly higher following the second meal (p < 0.01) on the simulated night shift. These findings confirm our previous observations of raised postprandial TAG and glucose at night, and show that sequential meal ingestion has a more pronounced effect on subsequent lipid than carbohydrate tolerance.
PMID: 15646240 [PubMed - indexed for MEDLINE]
1: Nutr Health. 2002;16(2):133-41. Links
Postprandial responses of glucose, insulin and triglycerides: influence of the timing of meal intake during night work.
* Knutsson A,
* Karlsson B,
* Ornkloo K,
* Landstrom U,
* Lennernas M,
* Eriksson K.
Department of Public Health and Clinical Medicine, Occupational Medicine, Umea University, Sweden.
[email protected]
The objective was to study the postprandial responses of glucose, insulin and triglycerides to meal intake at different clock times during night work. Eleven night shift working nurses participated. Identical test meals were ingested at 19:30, 23:30 and 03:30, and contained 440 kcal/1,860
kJ of energy (33 E% fat, 51 E% carbohydrate, 16 E% protein). The food intake was standardized three days before the first test meal. Blood samples were drawn just before the test meals were ingested and thereafter at 30, 60, 90, 120, 180 and 240 minutes. The postprandial responses were estimated as the total area under the curve (AUC) and significance testing was done using repeated measures ANOVA. The highest insulin level was found after meal intake at 23:30, and the lowest after meal intake 03:30. The glucose response showed the same pattern. The insulin response to food intake in night working nurses is more pronounced in the night compared with morning and evening. The results would have implications for metabolic and cardiovascular disorders in night workers.
PMID: 12102366 [PubMed - indexed for MEDLINE]
Postprandial hormone and metabolic responses amongst shift workers in Antarctica.
* Lund J,
* Arendt J,
* Hampton SM,
* English J,
* Morgan LM.
British Antarctic Survey, High Cross, Madingley Road, Cambridge, UK.
The circadian rhythms of many night-shift workers are maladapted to their imposed behavioural schedule, and this factor may be implicated in the increased occurrence of cardiovascular disease (CVD) reported in shift workers. One way in which CVD risk could be mediated is through inappropriate hormonal and metabolic responses to meals. This study investigated the responses to standard meals at different circadian times in a group of night-shift workers on a British Antarctic Survey station at Halley Bay (75 degrees S) in Antarctica. Twelve healthy subjects (ten men and two women) were recruited. Their postprandial hormone and metabolic responses to an identical mixed test meal of 3330 kJ were measured on three occasions: (i) during daytime on a normal working day, (ii) during night-time at the beginning of a period of night-shift work, and (iii) during the daytime on return from night working to daytime working. Venous blood was taken for 9 h after the meal for the measurement of glucose, insulin, triacylglycerol (TAG) and non-esterified fatty acids. Urine was collected 4-hourly (longer during sleep) on each test day for assessment of the circadian phase via 6-sulphatoxymelatonin (aMT6s) assay. During normal daytime working, aMT6s acrophase was delayed (7.7+/-1.0 h (s.e.m.)) compared with that previously found in temperate zones in a comparable age-group. During the night shift a further delay was evident (11.8+/-1.9 h) and subjects' acrophases remained delayed 2 days after return to daytime working (12.4+/-1.8 h). Integrated postprandial glucose, insulin and TAG responses were significantly elevated during the night shift compared with normal daytime working. Two days after their return to daytime working, subjects' postprandial glucose and insulin responses had returned to pre-shift levels; however, integrated TAG levels remained significantly elevated. These results are very similar to those previously found in simulated night-shift conditions; it is the first time such changes have been reported in real shift workers in field conditions. They provide evidence that the abnormal metabolic responses to meals taken at night during unadapted night shifts are due, at least in part, to a relative insulin resistance, which could contribute to the documented cardiovascular morbidity associated with shift work. When applied to the 20% of the UK workforce currently employed on shift work, these findings have major significance from an occupational health perspective.
PMID: 11739022 [PubMed - indexed for MEDLINE]
Altered postprandial hormone and metabolic responses in a simulated shift work environment.
* Ribeiro DC,
* Hampton SM,
* Morgan L,
* Deacon S,
* Arendt J.
School of Biological Sciences, University of Surrey, Guildford, UK.
The circadian rhythms of most night shift workers do not adapt fully to the imposed behavioural schedule, and this factor is considered to be responsible for many of the reported health problems. One way in which such disturbances might be mediated is through inappropriate hormonal and metabolic responses to meals, on the night shift. Twelve healthy subjects (four males and eight females) were studied on three occasions at the same clock time (1330 h), but at different body clock times, after consuming test meals, first in their normal environment, secondly after a forced 9 h phase advance (body clock time approximately 2230 h) and then again 2 days later in the normal environment. They were given a low-fat pre-meal at 0800 h, then a test meal at 1330 h with blood sampling for the following 9 h. Parameters measured included plasma glucose, non-esterified fatty acids (NEFAs), triacylglycerol (TAG), insulin, C-peptide, proinsulin and glucose-dependent insulinotropic polypeptide, and urinary 6-sulphatoxymelatonin. In contrast with a previous study with a high-fat pre-meal, postprandial glucose and insulin responses were not affected by the phase shift. However, basal plasma NEFAs were lower immediately after the phase shift (P < 0.05). Incremental (difference from basal) TAG responses were significantly higher (P < 0.05) immediately after the phase shift compared with before. Two-day post-phase shift responses showed partial reversion to baseline values. This study suggests that it takes at least 2 days to adapt to eating meals on a simulated night shift, and that the nutritional content of the pre-meals consumed can have a marked effect on postprandial responses during a simulated phase shift. Such findings may provide a partial explanation for the increased occurrence of cardiovascular disease reported in shift workers.
PMID: 9846159 [PubMed - indexed for MEDLINE]
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