International SportMed Journal - Volume 4, Issue 6, 2003
Volume 4, Issue 6, 2003
Adaptation to a high-fat diet for endurance exercise : review of potential underlying mechanisms : review articleSource: International SportMed Journal 4, pp 1 –11 (2003)More Less
Ingestion of a high-fat diet for as little as 5-10 days results in a significant increase in fat oxidation and a decrease in muscle glycogen utilisation during exercise. In this review, the putative mechanisms underlying the effect of high-fat feeding on altered substrate metabolism during exercise are discussed, including mitochondrial adaptations, such as changes in the enzymes involved in the uptake and oxidation of fatty acids, the effect of increased availability of plasma free fatty acids and the possible role of the glucose-fatty acid cycle, as well as the possible regulatory role of low glycogen stores per se, as opposed to dietary intervention, in altering substrate metabolism. In addition, the high-fat diet-induced reduction in glucose tolerance and / or insulin sensitivity as a result of increased intramuscular triglyceride stores and altered insulin signalling, as well as the interaction with training and dietary fatty acid composition, is discussed. Finally, the implications of these adaptations on exercise performance and resistance to fatigue, exploring the possible role of pyruvate dehydrogenase (PDH) and the sympathetic nervous system in mediating these effects will be briefly addressed.
Source: International SportMed Journal 4, pp 1 –9 (2003)More Less
The aim of this review is to outline documented foetal responses to graded maternal exercise. These responses included changes in baseline heart rate and its variability or occurrence of bradycardia. These were reviewed with respect to causes for their occurrence and subsequent consequences. The suggestion that a 'symptom-limited- exercise test could serve as a stress test to highlight 'at-risk' foetuses was also reviewed. A literature search was performed using MEDLINE (1983-2003), Google and PubMed. Studies that directly assessed the foetal haemodynamic response to exercise were reviewed, including foetal heart rate response and changes in umbilical and uterine artery blood flow. Reference was made to human and animal studies. The findings suggest that a single bout of 'symptom limited' exercise does not adversely affect the foetal heart rate in uncomplicated pregnancies with appropriately grown foetuses. Isolated bradycardias have been reported, but these occur in cases of strenuous exertion with peripheral venous pooling of blood. This may reflect an intrinsic foetal response to maintain perfusion and oxygenation when uterine blood flow is transiently reduced. Nonetheless, there is no evidence in the literature that those cases of exercise-induced changes in variability or bradycardias are associated with adverse perinatal outcome.
Author Enette Larson-MeyerSource: International SportMed Journal 4, pp 1 –14 (2003)More Less
Regular postpartum exercise is likely to have many health benefits which may include promoting body fat / body weight loss; promoting aerobic fitness and strength, optimising bone health; improving mood and promoting regular lifelong exercise habits in the mother and her offspring. While research addressing the health benefits of postpartum exercise is not extensive, published studies conducted mostly in lactating women have suggested that moderate exercise improves aerobic fitness, HDL cholesterol level and insulin sensitivity, but does not necessarily promote greater loss of pregnancy-associated body weight / body fat. This may be because exercise while lactating may also stimulate energy intake and reduce non-exercise physical activity level (thus prohibiting negative energy balance). Well-controlled randomised trials are needed to determine whether postpartum exercise improves bone health, mental health or offspring's health, but cross-sectional and longitudinal studies support the contention that postpartum exercise may enhance maternal psychological well-being and promote physical activity habits in offspring. While little data is available from which to base postpartum exercise recommendations, published guidelines suggest that medical clearance be obtained before initiation and that exercise routines be resumed slowly and gradually progressed (based on the woman's physical capabilities) to pre-pregnant training level or goal of exercising aerobically for 25-60 min., 3-6 days / week. The postpartum exercise plan should also incorporate regular resistance-training exercises and, if desired, mother and baby exercise sessions. Studies have suggested that postpartum women will be most successful in getting regular exercise if they have a plan and are confident in their ability to carry it out.
Author Pauline ChiarelliSource: International SportMed Journal 4, pp 1 –10 (2003)More Less
Objective: To examine the effectiveness of various interventions designed to promote urinary continence in postpartum women and make recommendations regarding pelvic floor muscle exercise programmes during pregnancy and in the postpartum.
Data sources: MEDLINE, CINAHL, Cochrane and PEDRo databases were searched for evidence of the efficacy of pelvic floor exercises in the prevention of urinary incontinence during pregnancy and in the postpartum.
Study selection: Only studies with sample sizes large enough to provide enough power, using randomised controlled trials with blinded assessment of outcomes were considered for this part of the analysis. Only studies not using exercise adjuncts such as biofeedback or exercise equipment within the exercise intervention were included.
Conclusions: Postpartum urinary incontinence is common but preventable using both prenatal and postnatal pelvic floor exercise interventions.
Source: International SportMed Journal 4, pp 1 –9 (2003)More Less
Exercise can drain the body of water and energy, yet research shows that when exercise is conducted at moderate intensity, the breast milk composition of postpartum women is not compromised. Furthermore, infant growth of chronically active mothers does not differ from that of sedentary mothers. Mothers who exercise experience positive health effects. Some, but not all, research suggests moderate exercise leads to improved blood lipids, cardiovascular fitness, bone mineral density, and body composition. Although more research is needed on the effects of exercise on bone health and body composition, current research suggests that lactating women can continue or even add exercise to their daily routine as long as this routine includes proper hydration, moderate-intensity exercise, and intake of sufficient calories.
Author Siv MorkvedSource: International SportMed Journal 4, pp 1 –19 (2003)More Less
Objective: Urinary incontinence is a chronic health complaint, which severely reduces quality of life. Many sufferers report effects on their social, domestic, physical, occupational and leisure activities. Female urinary incontinence is often considered a problem primarily occurring during pregnancy and after childbirth. The aim of this article is to review the literature addressing pelvic floor muscle training in the prevention and treatment of postpartum urinary incontinence.
Data sources: Only full publications of prospective controlled studies were included. Urinary incontinence was the primary outcome variable, and language of publication was English. Relevant studies were identified by computerised searches in MEDLINE, CINAHL, the Cochrane Controlled Trials Register.
Study selection : Three randomised controlled trials assessing the effect of pelvic floor muscle training during pregnancy in the prevention and treatment of postpartum urinary incontinence were found. Two studies with a matched controlled design and five randomised controlled trials assessing the effect of postpartum pelvic floor muscle training were identified.
Data extraction: In the studies included, pelvic floor muscle training was the main intervention.
Data synthesis: Different training protocols have been used and the reported effect on urinary incontinence differs. It appears that studies with high-intensity pelvic floor muscle training and close follow-up show the best results.
Conclusions: This review suggests that pregnant and postpartum women should be encouraged to perform pelvic floor muscle training to prevent and / or treat urinary incontinence. Health services for women during pregnancy and after delivery should be increased, and strategies to prevent and treat urinary incontinence need to be implemented. Another important issue is that pelvic floor muscle training should be incorporated in sports and exercise groups in general, to reach women of all levels of physical fitness.