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- Sjödin, Anders M, et al.
(författare)
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The influence of physical activity on BMR
- 1996
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 28:1, s. 85-91
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Tidskriftsartikel (refereegranskat)abstract
- In addition to factors such as fat free mass, hormonal status, genetics and energy balance, previous physical activity has been shown to influence energy turnover during resting (RMR = resting metabolic rate) or basal conditions(BMR = basal metabolic rate). This article presents data on BMR from elite endurance athletes (4 female and 4 male), at least 39 h after their last training session, in comparison with sedentary nonathletic controls matched for sex and fat free mass (FFM). Comparisons with theoretical calculations of BMR were also made. The athletes were shown to have a significantly higher BMR than was expected from calculations based on body mass (16%, P < 0.05) or body composition (12%, P < 0.05). There were no corresponding differences found in the nonathletic control group. The athletes had a 13% higher (P < 0.001) BMR than controls if related to FFM and 16% (P = 0.001) if related to both FFM and fat mass (FM). The athletes were also found to have 10% lower R-values (P < 0.01) indicating higher fat oxidation. The conformity of these findings with the present literature and the possible mechanisms behind them as well as its influence on theoretical calculations of energy turnover (ET) based on activity factors expressed as multiples of RMR are further discussed.
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| 4. |
- Holmbäck, Ulf C., et al.
(författare)
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Endocrine responses to nocturnal eating : Possible implications for night work
- 2003
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Ingår i: European Journal of Nutrition. - : Springer Science and Business Media LLC. - 1436-6207 .- 1436-6215. ; 42:2, s. 75-83
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Tidskriftsartikel (refereegranskat)abstract
- Background: Night work is becoming more common and shift workers display several metabolic disturbances. Aim: To study the endocrine responses in relation to time of day during a 24-h period and how dietary macronutrient composition affects these responses. Design: Seven males (26-43 y and 19.9-26.6 kg · m-2) were studied in a crossover design. Isocaloric diets described as highcarbohydrates (HC; 65 energy percent (E%) carbohydrates and 20E% fat) or high-fat (HF; 40E% carbohydrates and 45E% fat) were given. After a 6-day diet adjustment period, the subjects were kept awake for 24 h in a metabolic unit and were served an isocaloric meal (continuation of respective diet) every 4-h. Blood samples were taken throughout the 24-h period. Results: Insulin and leptin responses to meal intake differed with respect to time of day (p ≤ 0.05). Time of day affected glucagon, thyroid stimulating hormone (TSH), free thyroxin (fT4), total triiodothyronine (tT3), cortisol, chromogranin A (CgA) and pancreatic polypeptide (PP) concentrations (p ≤ 0.05). Meal intake decreased cortisol concentration after meals at 0800, 1200 and 0400 but not at 1600, 2000 and 0000 h. The PP's postprandial increase was greater during 0800-1600 h compared to 2000-0800 h. With the HC meals, lower glucagon and CgA concentrations (p ≤ 0.05), and a tendency for lower tT3 concentrations (p = 0.053) were observed compared to the HF meals. Conclusion: Insulin, PP, TSH, fT4, cortisol and leptin responses to meal intake differed with respect to time of day. The decreased evening/nocturnal responses of cortisol and PP to meal intake indicate that nocturnal eating and night work might have health implications.
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| 5. |
- Löwden, Arne, et al.
(författare)
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Time of day type of food--relation to mood and hunger during 24 hours of constant conditions
- 2001
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Ingår i: Journal of Human Ergology. - 0300-8134 .- 1884-3964. ; 30:1-2, s. 381-386
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Tidskriftsartikel (refereegranskat)abstract
- A six-day high-carbohydrate meal (HC; 65 E% (energy percent) carbohydrates, 20 E% fat and 15 E% protein) and a six-day high-fat meal (HF; 40 E% carbohydrates, 45 E% fat and 15 E% protein) were given to seven healthy subjects in a crossover design. On the last day subjects were kept awake for 24 hours in a metabolic laboratory while substrate utilisation and energy expenditure were measured by indirect calorimetry. The subjects were given isocaloric meals every four hours. Results showed that hunger decreased at night (F = 4.2, p < 0.05) and linearly increased after meal intake. Macronutrient composition (fat/carbohydrates) seemed to be of less importance for hunger. Hunger and thirst were found to be strongly associated with gastrointestinal substances, for hunger the strongest being a negative correlation with triacylglycerol (partial correlation = -0.39). It is suggested that it might not be necessary for shift workers to eat full portions at night but that satiation will occur with less food. Possibly lack of adjustment of nocturnal food intake might be one reason why overweight is common in shift work populations.
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