Challenges faced by shiftworkers

Transcription

1 Challenges faced by shiftworkers Philip Tucker Currently on secondment to the Stress Research Institute, Stockholm University

2 Shiftwork & disease Obesity Cardio-vascular disease (CVD) Peptic ulcers Gastrointestinal disorders Diabetes Metabolic syndrome Knutsson (2003)

3 Shiftworkers dietary habits No overall difference in energy / nutrient intake e.g. Lennernäs et al (1995) Distribution changes: Higher energy intake at night (?) Assis et al (2003) More snacking at night e.g. Lennernäs et al (1995)

4 Why can shiftwork cause problems? We evolved on a rhythmic planet Early organisms simply responded to changes Advantageous to anticipate changes Most species evolved an internal body clock Reflected in human circadian rhythms

5 Homo Sapiens is a diurnal species We habitually sleep at night! Our night vision is poor despite vision being our dominant sense Asking someone to ignore their diurnal nature is a bit like asking them to become aquatic!

6 Nocturnal eating effects Normal circadian rhythms: Day time: Glucose metabolism & fat storage (Eating) Night time: Glucose sparing & fat metabolism (Fasting) Inverted eating cycle: Leptin Postprandial glucose, insulin & arterial pressure Sheer et al (2009) Obesity, diabetes & hypertension

7 Nocturnal eating effects Night work: Triglycerides, glucose tolerance e.g. Lundt et al (2001) Serum total cholesterol, LDL, LDL:HDL ratio Lennernäs et al (1995) CVD risk Gastric ph with evening meal Sanders (1992) Absorptive system is less willing to handle food at night

8 Adjusting to a nocturnal routine Should we promote adjustment? Difficult to fully adjust Disruption of circadian rhythms as pathology? Zvonic et al (2007) Mismatch with family / social rhythm

9 Maintaining a diurnal routine Better to minimise circadian disruption? Maintain normal diurnal eating pattern Restrict energy intake at night

10 Obesity & sleep Effects of sleep deprivation: Leptin, ghrelin Appetite Holmbäck et al (2002) Energy consumption from snacks Nedeltcheva et al (2009)

11 Obesity & health behaviour Weight-gain among night shift workers kg (compared to 0.9 kg) over 2 years - Food intake - Napping - Exercise - Energy expenditure Geliebter et al (2000)

12 Nutrition management strategy General guidelines Restrict energy intake between 00:00 06:00 Eat at beginning and end of shift Avoid large meals 1-2 hours before main sleep Provide choice: Complete meals, vegetarian options, high quality snacks Provide appropriate dining facilities & opportunities (i.e. breaks) Lifestyle: Exercise, regular meal times, good sleep hygiene

13 Nutrition management strategy Shiftwork guidelines: When to eat Eat breakfast before day sleep (to avoid waking from hunger) Stick to a normal diurnal eating pattern Design shift schedules to allow adequate time between shifts for sleep, meal preparation, etc

14 Nutrition management strategy Shiftwork guidelines: What to eat Three satiating meals per 24 hours, each of 20-35% of daily intake More frequent eating if there are higher energy needs Avoid convenience foods & high carbohydrate foods during the shift Choose vegetable soups, salads, fruit salads, yoghurt, wholegrain sandwiches, cheese or cottage cheese (topped with fruit slices), boiled eggs, nuts, green tea. Avoid sugar rich products & non-fibre carbohydrate foods e.g. soft drinks, bakery items, sweets, white bread

15 Further information Lowden, A., de Castro Moreno, C., Holmbäck, U., Lennernäs, M. & Tucker, P. (2010). Eating and shift work - effects on habits, metabolism, and performance. Scandinavian Journal of Work, Environment & Health, 36(2), Available (free) at: p.t.tucker@swansea.ac.uk