Circannual rhythm of exercise metabolic rate in humans

Zahorska-Markiewicz, Barbara; Markiewicz, A

doi:10.1007/bf01015221

Cited by 7 publications

(6 citation statements)

References 7 publications

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“…We found no annual variation in self-reported physical activity or measured BMI but a strong seasonal variation in WHR. Variation in WHR represents variation in abdominal fat mass and is supported by a study showing body fat to be highest in the summer and early fall (29). Zahorska-Markiewicz and Markiewicz (29) suggest that fat is the main fuel oxidized in the winter, and a lower utilization of fat as a metabolic substrate in summer could account for accumulation of body fat.…”

Section: Discussionmentioning

confidence: 95%

“…Variation in WHR represents variation in abdominal fat mass and is supported by a study showing body fat to be highest in the summer and early fall (29). Zahorska-Markiewicz and Markiewicz (29) suggest that fat is the main fuel oxidized in the winter, and a lower utilization of fat as a metabolic substrate in summer could account for accumulation of body fat. Visceral fat is readily mobilized by lifestyle changes in energy balance (30), making seasonal variation in WHR a plausible explanation for the observed inverse relationship between testosterone levels and WHR during the year.…”

Section: Discussionmentioning

confidence: 95%

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Seasonal Variation of Testosterone and Waist to Hip Ratio in Men: The Tromsø Study

Svartberg

Jorde

Sundsfjord

et al. 2003

The Journal of Clinical Endocrinology &Amp; Metabolism

100

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Studies of seasonal variation in male testosterone levels show contradictory results. We report here a cross-sectional study of the seasonal variation in total and free testosterone, LH, and SHBG levels in 1548 men living in north Norway, a population exposed to a wide seasonal variation in temperature and daylight. Total testosterone showed a bimodal seasonal variation (P < 0.001) with a small peak in February, the nadir in June, and a more prominent peak in October and November. Free testosterone also showed a significant seasonal pattern (P < 0.001), with the peak in December and the nadir in August. These patterns persisted after adjusting for age and waist to hip ratio (P < 0.001). Lowest testosterone levels occurred in months with the highest temperatures and longest hours of daylight. Waist to hip ratio paralleled the change in daylight and temperature, with the highest values during the summer and was thus inversely related to the seasonal testosterone variation. The variations in hormone levels were large, with a 31% difference between the lowest and highest monthly mean level of free testosterone. Prospective studies are needed to establish the direction of the association and its etiology.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 95%

Seasonal Variation of Testosterone and Waist to Hip Ratio in Men: The Tromsø Study

Svartberg

Jorde

Sundsfjord

et al. 2003

The Journal of Clinical Endocrinology &Amp; Metabolism

100

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show abstract

“…In their study of plasma glucose in humans, Suarez and Barrett-Connor (14) noticed that a history of recent weight gain corresponded to the season of maximum fasting plasma glucose, which was winter as was mentioned above. Measurements by Zahorska-Markiewicz and Markiewicz (35) in Poland indicated that physical fitness is higher in summer, that fat is the main fuel in winter, and that carbohydrate is the main fuel in summer, as judged by the respiratory quotient. The efficiency of weight loss by dietary restriction in obese women was season dependent, with the most marked weight loss in spring and the worst results in winter (36).…”

Section: Discussionmentioning

confidence: 99%

Seasonality in Glycosylated Hemoglobin in Normal Subjects: Does Seasonal Incidence in Insulin-Dependent Diabetes Suggest Specific Etiology?

MacDonald¹,

Liston²,

Carlson³

1987

Diabetes

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Seasonality in the diagnosis of insulin-dependent diabetes mellitus (IDDM), i.e., increased incidence in winter, was the impetus for this study of seasonality in glycosylated hemoglobin levels in nondiabetics. Glycosylated hemoglobin levels of 35 nondiabetic children and adults were highest at the ends of autumn and winter and lowest at the ends of spring and summer (P less than 10(-4)). This result is consistent with reports of seasonal variation in blood glucose, with the highest levels occurring in winter, as well as reports that suggest an internal milieu of increased counterinsulin action in winter due to seasonality in counterinsulin hormones, dietary factors, body weight, amount of exercise, growth rates in children, and ambient temperature. IDDM is caused by the gradual destruction of the pancreatic insulin-producing cells via lymphocytic infiltration--a process that may occur over years. We conclude that a decreased carbohydrate tolerance associated with winter can explain the seasonal variation in the incidence of IDDM and that this seasonality is caused by the precipitation of overt carbohydrate intolerance in individuals with already seriously compromised insulin secretory capacity. This implies that seasonality is not very formative about the cause of the destruction of pancreatic insulin-producing cells.

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“…Thus, exercise provides an excellent opportunity to study the dynamic balance between oxidant challenge and antioxidant defense in a biological system. Although abundant data on the influence of exercise on oxidant/antioxidant status in men and women exist, to the best of our knowledge the only reports of circannual rhythms of exercise are the one by Zahorska-Markiewicz and Markiewicz (1984), which deals with variables like heart and metabolic rate, and the recent data by Pivarnik et al (2003) about seasonal frequency, intensity and energy expenditure in exercise.…”

Section: Introductionmentioning

confidence: 95%

The influence of season on oxidant–antioxidant status in trained and sedentary subjects

et al. 2006

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Circannual rhythm of exercise metabolic rate in humans

Cited by 7 publications

References 7 publications

Seasonal Variation of Testosterone and Waist to Hip Ratio in Men: The Tromsø Study

Seasonal Variation of Testosterone and Waist to Hip Ratio in Men: The Tromsø Study

Seasonality in Glycosylated Hemoglobin in Normal Subjects: Does Seasonal Incidence in Insulin-Dependent Diabetes Suggest Specific Etiology?

The influence of season on oxidant–antioxidant status in trained and sedentary subjects

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