Fuel metabolism in men and women during and after long-duration exercise

1998 ◽  
Vol 85 (5) ◽  
pp. 1823-1832 ◽  
Author(s):  
Tracy J. Horton ◽  
Michael J. Pagliassotti ◽  
Karen Hobbs ◽  
James O. Hill
Keyword(s):  
Metabolic Response ◽  
Carbohydrate Oxidation ◽  
Fuel Oxidation ◽  
Men And Women ◽  
Fuel Metabolism ◽  
Lipolytic Action ◽  
Long Duration ◽  
Separate Control ◽  
Gender Based ◽  
Response To Exercise

This study aimed to determine gender-based differences in fuel metabolism in response to long-duration exercise. Fuel oxidation and the metabolic response to exercise were compared in men ( n = 14) and women ( n = 13) during 2 h (40% of maximal O2 uptake) of cycling and 2 h of postexercise recovery. In addition, subjects completed a separate control day on which no exercise was performed. Fuel oxidation was measured using indirect calorimetry, and blood samples were drawn for the determination of circulating substrate and hormone levels. During exercise, women derived proportionally more of the total energy expended from fat oxidation (50.9 ± 1.8 and 43.7 ± 2.1% for women and men, respectively, P < 0.02), whereas men derived proportionally more energy from carbohydrate oxidation (53.1 ± 2.1 and 45.7 ± 1.8% for men and women, respectively, P < 0.01). These gender-based differences were not observed before exercise, after exercise, or on the control day. Epinephrine ( P < 0.007) and norepinephrine ( P < 0.0009) levels were significantly greater during exercise in men than in women (peak epinephrine concentrations: 208 ± 36 and 121 ± 15 pg/ml in men and women, respectively; peak norepinephrine concentrations: 924 ± 125 and 659 ± 68 pg/ml in men and women, respectively). As circulating glycerol levels were not different between the two groups, this suggests that women may be more sensitive to the lipolytic action of the catecholamines. In conclusion, these data support the view that different priorities are placed on lipid and carbohydrate oxidation during exercise in men and women and that these gender-based differences extend to the catecholamine response to exercise.

The Effect of Sodium Acetate Ingestion on the Metabolic Response to Prolonged Moderate-Intensity Exercise in Humans

2013 ◽  
Vol 23 (4) ◽  
pp. 357-368 ◽  
Author(s):  
Gordon I. Smith ◽  
Asker E. Jeukendrup ◽  
Derek Ball
Keyword(s):  
Sodium Acetate ◽  
Metabolic Response ◽  
Fat Oxidation ◽  
Substrate Utilization ◽  
Carbohydrate Oxidation ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Carbohydrate Utilization ◽  
Response To Exercise ◽  
Exercise In Humans

At rest, administration of the short-chain fatty acid acetate suppresses fat oxidation without affecting carbohydrate utilization. The combined effect of increased acetate availability and exercise on substrate utilization is, however, unclear. With local ethics approval, we studied the effect of ingesting either sodium acetate (NaAc) or sodium bicarbonate (NaHCO3) at a dose of 4 mmol·kg-1 body mass 90 min before completing 120 min of exercise at 50% VO2peak. Six healthy young men completed the trials after an overnight fast and ingested the sodium salts in randomized order. As expected NaAc ingestion decreased resting fat oxidation (mean ± SD; 0.09 ± 0.02 vs. 0.07 ± 0.02 g·min-1 pre- and post-ingestion respectively, p < .05) with no effect upon carbohydrate utilization. In contrast, NaHCO3 ingestion had no effect on substrate utilization at rest. In response to exercise, fat and CHO oxidation increased in both trials, but fat oxidation was lower (0.16 ± 0.10 vs. 0.29 ± 0.11 g·min-1, p < .05) and carbohydrate oxidation higher (1.67 ± 0.35 vs. 1.44 ± 0.22 g·min-1, p < .05) in the NaAc trial compared with the NaHCO3 trial during the first 15 min of exercise. Over the final 75 min of exercise an increase in fat oxidation and decrease in carbohydrate oxidation was observed only in the NaAc trial. These results demonstrate that increasing plasma acetate concentration suppresses fat oxidation both at rest and at the onset of moderate-intensity exercise.

The Metabolic Response to Exercise and Exhaustion in Normal and Growth-Hormone-Deficient Children

1974 ◽  
Vol 52 (3) ◽  
pp. 575-582 ◽  
Author(s):  
Jeremy S. D. Winter
Keyword(s):  
Growth Hormone ◽  
Fatty Acid ◽  
Healthy Subjects ◽  
Metabolic Response ◽  
Work Capacity ◽  
Serum Free Fatty Acid ◽  
Deficient Subject ◽  
Sugar Levels ◽  
Response To Exercise ◽  
Secondary Rise

The effects of exhausting bicycle exercise at close to maximal work capacity upon circulating levels of hormones and energy substrates in 4 fasting growth-hormone-deficient and 15 fasting healthy subjects (aged 13–18 years) have been studied. As expected, only the healthy subjects showed a rise in plasma growth hormone (GH) levels. In both groups plasma insulin tended to fall, but the decline was more prolonged in the GH-de-ficient group. Plasma Cortisol levels rose in both groups with the exception of one adrenocorticotropin (ACTH)-deficient subject. Blood sugar levels were well-maintained in all but this ACTH-deficient subject, whereas both groups showed marked lactate accumulation. Both groups demonstrated an initial fall and then a secondary rise in serum free fatty acid concentrations; however, fatty acid levels were lower in the GH-deficient group and there was no post-exercise overshoot, suggesting a possible reduction in the effectiveness of lipid mobilization.

Hidden Fissures and Epidemics in Plain Sight: The Common Paths of Syphilis and HIV in Russia

2021 ◽  
Vol 31 (1) ◽  
pp. 113-142
Keyword(s):  
20Th Century ◽  
Contemporary Culture ◽  
Historical Sources ◽  
Men And Women ◽  
Early 21St Century ◽  
Women Living With Hiv ◽  
The Social ◽  
Gender Based ◽  
Closed Door ◽  
Social And Cultural Factors

The paper examines and compares two epidemics in Russia: syphilis in the first quarter of 20th century and HIV in the early 21st century. The author considers both epidemics from the standpoint of the social sciences by applying the concept of vulnerability to underline the social and cultural factors that cause one social group to be more susceptible to a disease than another. The article focuses on gender-based vulnerability and maintains that both epidemics follow a single, structurally similar scenario. The author shows that the vulnerability of women during both the syphilis and HIV epidemics depends upon the clear continuity in the way gender roles and expectations and the relationships between men and women were structured during the early days of the USSR and in present-day Russia. The article analyzes how stigma arises and how in both eras inequality of power and expectations for men and women formed the main channel for transmission of disease. The paths along which modern epidemics spread have been mostly inherited from the epidemics of past centuries, and in particular the HIV epidemic is following a pattern derived from the syphilis epidemic. More precisely, the current epidemics exploit the same vulnerability of certain groups, vulnerability rooted in the past and still manifest in the norms and relations in contemporary culture and society where one group is much more exposed than the other. The article relies on historical sources, in particular Lev Friedland"s book Behind a Closed Door: Observations of a Venereologist published in 1927, for its account of the syphilis epidemic in the early 20th century and on the author"s own research into the experience of women living with HIV in contemporary Russia.

Metabolic response in type I and type II muscle fibers during a 30-s cycle sprint in men and women

1999 ◽  
Vol 87 (4) ◽  
pp. 1326-1332 ◽  
Author(s):  
Mona Esbjörnsson-Liljedahl ◽  
Carl Johan Sundberg ◽  
Barbara Norman ◽  
Eva Jansson
Keyword(s):  
Gender Difference ◽  
Glycogen Content ◽  
Metabolic Response ◽  
Muscle Fibers ◽  
Type I ◽  
Type Ii ◽  
Men And Women ◽  
Sprint Exercise ◽  
Exercise Induced ◽  
Type I Fibers

The acute metabolic response to sprint exercise was studied in 20 male and 19 female students. We hypothesized that the reduction of muscle glycogen content during sprint exercise would be smaller in women than in men and that a possible gender difference in glycogen reduction would be higher in type II than in type I fibers. The exercise-induced increase in blood lactate concentration was 22% smaller in women than in men. A considerable reduction of ATP (50%), phosphocreatine (83%), and glycogen (35%) was found in type II muscle fibers, and it did not differ between the genders. A smaller reduction of ATP (17%) and phosphocreatine (78%) was found in type I fibers, and it did not differ between the genders. However, the exercise-induced reduction in glycogen content in type I fibers was 50% smaller in women than in men. The hypothesis was indeed partly confirmed: the exercise-induced glycogen reduction was attenuated in women compared with men, but the gender difference was in type I rather than in type II fibers. Fiber-type-specific and gender-related differences in the metabolic response to sprint exercise might have implications for the design of training programs for men and women.

Muscle metabolism during exercise in young and older untrained and endurance-trained men

1993 ◽  
Vol 75 (5) ◽  
pp. 2125-2133 ◽  
Author(s):  
A. R. Coggan ◽  
A. M. Abduljalil ◽  
S. C. Swanson ◽  
M. S. Earle ◽  
J. W. Farris ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Muscle Mass ◽  
Citrate Synthase ◽  
Metabolic Response ◽  
Plantar Flexion ◽  
Muscle Metabolism ◽  
Resonance Spectroscopy ◽  
Age Related ◽  
Rate Of Increase ◽  
Response To Exercise

To examine effects of aging and endurance training on human muscle metabolism during exercise, 31P magnetic resonance spectroscopy was used to study the metabolic response to exercise in young (21–33 yr) and older (58–68 yr) untrained and endurance-trained men (n = 6/group). Subjects performed graded plantar flexion exercise with the right leg, with metabolic responses measured using a 31P surface coil placed over the lateral head of the gastrocnemius muscle. Muscle biopsy samples were also obtained for determination of citrate synthase activity. Rate of increase in P(i)-to-phosphocreatine ratio with increasing power output was greater (P < 0.01) in older untrained [0.058 +/- 0.022 (SD) W-1] and trained men (0.042 +/- 0.010 W-1) than in young untrained (0.038 +/- 0.017 W-1) and trained men (0.024 +/- 0.010 W-1). Plantar flexor muscle cross-sectional area and volume (determined using 1H magnetic resonance imaging) were 11–12% (P < 0.05) and 16–18% (P < 0.01) smaller, respectively, in older men. When corrected for this difference in muscle mass, age-related differences in metabolic response to exercise were reduced by approximately 50% but remained significant (P < 0.05). Citrate synthase activity was approximately 20% lower (P < 0.001) in older untrained and trained men than in corresponding young groups and was inversely related to P(i)-phosphocreatine slope (r = -0.63, P < 0.001). Age-related reductions in exercise capacity were associated with an altered muscle metabolic response to exercise, which appeared to be due to smaller muscle mass and lower muscle respiratory capacity of older subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Do exist gender differences in skin temperature of lower limbs following exercise test in male and female cross-country skiers?

2021 ◽  
Author(s):  
M. Binek ◽  
Z. Drzazga ◽  
T. Socha ◽  
I. Pokora
Keyword(s):  
Skin Temperature ◽  
Exercise Test ◽  
Physiological Parameters ◽  
Lower Limbs ◽  
Metabolic Energy ◽  
Men And Women ◽  
Male And Female ◽  
Significant Difference ◽  
Cross Country ◽  
Response To Exercise

AbstractThe aim of study was to assess the skin temperature changes over selected muscles zones of the lower limbs following an exercise performed at similar relative external workload in 10 male and 6 female high-trained cross-country skiers. The first stage of experiment involved preliminary exercise to determine individual oxygen uptake VO2max and anaerobic threshold. The second stage experimental exercise consisted of 60 min running on treadmill with 80% of determined VO2max Thermographic imaging of lower limbs was performed, before, immediately after exercise and during recovery. Physiological parameters: VO2, MET—metabolic energy equivalent, heart rate and internal temperature were assessed at rest and at the end of exercise, respectively. Infrared thermography showed that at rest the skin temperature over lower limb muscles was significantly higher in men than in women. In response to exercise an increase in skin temperature over the studied muscles was significantly higher in women than men. Since was no significant difference in skin temperature in men and women after exercise. Before the test, no physiological parameter was significantly different in women and men. Exercise test reveled significant differences between men and women in some physiological parameters such as VO2 and MET. Our study showed that there are significant differences in lower limbs skin temperature between male and female at rest but not at the end of exercise test. Women in comparison with men had a greater increase in skin temperature in response to exercise and a persistence of elevated temperature over muscles of lower limbs after exercise.

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