1.
Effects of Endurance Training Intensity on Pulmonary Diffusing Capacity at Rest and after Maximal Aerobic Exercise in Young Athletes.
Dridi, R, Dridi, N, Govindasamy, K, Gmada, N, Aouadi, R, Guénard, H, Laher, I, Saeidi, A, Suzuki, K, Hackney, AC, et al
International journal of environmental research and public health. 2021;18(23)
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Intermittent exercise, where small bouts of exercise are performed over a short period of time and endurance exercise, has been shown to be particularly effective at improving different aspects of lung function. This randomised control trial aimed to determine the effects of intense endurance training compared too moderate endurance training on lung function. The results showed that lung function was improved following intense endurance training but not moderate endurance training. It was concluded that training intensity may be the most important factor when increasing lung function in athletes. This study could be used by professionals to recommend intense endurance training to improve exercise capacity in athletes.
Abstract
This study compared the effects of varying aerobic training programs on pulmonary diffusing capacity (TLCO), pulmonary diffusing capacity for nitric oxide (TLNO), lung capillary blood volume (Vc) and alveolar-capillary membrane diffusing capacity (DM) of gases at rest and just after maximal exercise in young athletes. Sixteen healthy young runners (16-18 years) were randomly assigned to an intense endurance training program (IET, n = 8) or to a moderate endurance training program (MET, n = 8). The training volume was similar in IET and MET but with different work intensities, and each lasted for 8 weeks. Participants performed a maximal graded cycle bicycle ergometer test to measure maximal oxygen consumption (VO2max) and maximal aerobic power (MAP) before and after the training programs. Moreover, TLCO, TLNO and Vc were measured during a single breath maneuver. After eight weeks of training, all pulmonary parameters with the exception of alveolar volume (VA) and inspiratory volume (VI) (0.104 < p < 0889; 0.001 < ES < 0.091), measured at rest and at the end of maximal exercise, showed significant group × time interactions (p < 0.05, 0.2 < ES < 4.0). Post hoc analyses revealed significant pre-to-post decreases for maximal heart rates (p < 0.0001, ES = 3.1) and improvements for VO2max (p = 0.006, ES = 2.22) in the IET group. Moreover, post hoc analyses revealed significant pre-to-post improvements in the IET for DM, TLNO, TLCO and Vc (0.001 < p < 0.0022; 2.68 < ES < 6.45). In addition, there were increases in Vc at rest, VO2max, TLNO and DM in the IET but not in the MET participants after eight weeks of training with varying exercise intensities. Our findings suggest that the intensity of training may represent the most important factor in increasing pulmonary vascular function in young athletes.
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Lipid Metabolism Links Nutrient-Exercise Timing to Insulin Sensitivity in Men Classified as Overweight or Obese.
Edinburgh, RM, Bradley, HE, Abdullah, NF, Robinson, SL, Chrzanowski-Smith, OJ, Walhin, JP, Joanisse, S, Manolopoulos, KN, Philp, A, Hengist, A, et al
The Journal of clinical endocrinology and metabolism. 2020;105(3)
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Following exercise, various metabolic changes occur which may be of benefit in fighting diseases such as type 2 diabetes and obesity. However, the degree of change may vary depending on whether the exercise has been performed pre or post meal consumption. This 6-week randomised crossover trial of 30 overweight or obese men aimed to determine the effect of exercising before or after breakfast on the use of fats and sugars by the body. The results showed that exercise before breakfast increased fat and sugar use in the body and also resulted in the alteration of eight genes associated with metabolism. Exercise before carbohydrate consumption also increased lipid use and improved insulin sensitivity, however body composition was similar regardless of when exercise was performed. It was concluded that exercising in the fasted state can optimise the body’s response without having to change intensity or effort. This study could be used by health care professionals to advise patients with obesity or overweight that exercising whilst in the fasted state could optimise their outcomes without having to increase exercise intensity or frequency.
Abstract
CONTEXT Pre-exercise nutrient availability alters acute metabolic responses to exercise, which could modulate training responsiveness. OBJECTIVE To assess acute and chronic effects of exercise performed before versus after nutrient ingestion on whole-body and intramuscular lipid utilization and postprandial glucose metabolism. DESIGN (1) Acute, randomized, crossover design (Acute Study); (2) 6-week, randomized, controlled design (Training Study). SETTING General community. PARTICIPANTS Men with overweight/obesity (mean ± standard deviation, body mass index: 30.2 ± 3.5 kg⋅m-2 for Acute Study, 30.9 ± 4.5 kg⋅m-2 for Training Study). INTERVENTIONS Moderate-intensity cycling performed before versus after mixed-macronutrient breakfast (Acute Study) or carbohydrate (Training Study) ingestion. RESULTS Acute Study-exercise before versus after breakfast consumption increased net intramuscular lipid utilization in type I (net change: -3.44 ± 2.63% versus 1.44 ± 4.18% area lipid staining, P < 0.01) and type II fibers (-1.89 ± 2.48% versus 1.83 ± 1.92% area lipid staining, P < 0.05). Training Study-postprandial glycemia was not differentially affected by 6 weeks of exercise training performed before versus after carbohydrate intake (P > 0.05). However, postprandial insulinemia was reduced with exercise training performed before but not after carbohydrate ingestion (P = 0.03). This resulted in increased oral glucose insulin sensitivity (25 ± 38 vs -21 ± 32 mL⋅min-1⋅m-2; P = 0.01), associated with increased lipid utilization during exercise (r = 0.50, P = 0.02). Regular exercise before nutrient provision also augmented remodeling of skeletal muscle phospholipids and protein content of the glucose transport protein GLUT4 (P < 0.05). CONCLUSIONS Experiments investigating exercise training and metabolic health should consider nutrient-exercise timing, and exercise performed before versus after nutrient intake (ie, in the fasted state) may exert beneficial effects on lipid utilization and reduce postprandial insulinemia.
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Effects of Oral Vitamin C Supplementation on Anxiety in Students: A Double-Blind, Randomized, Placebo-Controlled Trial.
de Oliveira, IJ, de Souza, VV, Motta, V, Da-Silva, SL
Pakistan journal of biological sciences : PJBS. 2015;18(1):11-8
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Vitamin C (ascorbic acid) is a well known anti-oxidant that has been studied in relation to anxious behaviour triggered by stressful situations. This study set out to examine the effects of vitamin C (50mg per day) or placebo on 42 high school students in a double-blind, randomised, placebo controlled trial. Levels of anxiety were measured before and after a 14 day supplementation of vitamin C or placebo using the Beck Anxiety Inventory. Plasma levels of vitamin C, heart rate and blood pressure were also measured. The results showed vitamin C supplementation reduced anxiety levels and increased plasma vitamin C levels. There was also a significant decrease in heart rate. There was no significant difference in blood pressure. The study concluded that vitamin C has a therapeutic affect on reducing anxiety levels. It was recommend high schools implement nutritional programs high in antioxidants such as vitamin C to reduce anxiety and improve academic performance.
Abstract
Vitamin C ascorbic acid) is a well-known antioxidant that is involved in anxiety, stress, depression, fatigue and mood state in humans. Studies have suggested that oxidative stress may trigger neuropsychological disorders. Antioxidants may play an important therapeutic role in combating the damage caused by oxidative stress in individuals that suffer from anxiety. In this context, it was hypothesized that oral vitamin C supplementation would reduce anxiety. However, few up to date studies have evaluated the consequences of oral vitamin C supplementation on anxiety in humans. The present study examined the effects of oral vitamin C supplements in 42 high school students, in a randomized, double-blind, placebo-controlled trial. The students were given either vitamin C (500 mg day(-1)) or placebo. Plasma concentrations of vitamin C and blood pressure were measured before the intervention and then one day after the intervention. Anxiety levels were evaluated for each student before and after 14 days following supplementation with the Beck Anxiety Inventory. Results showed that vitamin C reduced anxiety levels and led to higher plasma vitamin C concentration compared to the placebo. The mean heart rates were also significantly different between vitamin C group and placebo control group. Present study results not only provide evidence that vitamin C plays an important therapeutic role for anxiety but also point a possible use for antioxidants in the prevention or reduction of anxiety. This suggests that a diet rich in vitamin C may be an effective adjunct to medical and psychological treatment of anxiety and improve academic performance.