Is exercise effective for weight loss with ad libitum diet? Energy balance, compensation, and gender differences

Exercise generally results in less weight loss than expected and it is frequently observed that men and women do not respond equally to exercise for weight loss. This may be caused by differences in compensation by other components of energy balance or to differences in the energy expenditure of exercise observed between genders.     

Is exercise effective treatment for osteoarthritis of the knee?

OBJECTIVE: To review and determine the effectiveness of exercise treatment in osteoarthritis of the knee. METHODS: A computerised literature search of Medline was carried out searching between June 1966 and January 2000. RESULTS: Twenty three randomised controlled trials were identified from the literature. Only three trials were sufficiently powered. Small to moderate beneficial effects of exercise treatment were found for pain, small beneficial effects on disability outcome measures, and moderate to great beneficial effects were observed according to patient global assessment of effect. It was not possible to obtain evidence on the content of exercise interventions, as studies were hampered by lack of attention to proper concealment, reporting of adverse effects, and long term effects of exercise treatment. The lack of standard outcomes measures is also noted. CONCLUSIONS: The available evidence indicates beneficial short term effects of exercise treatment in patients with osteoarthritis of the knee. However, the number of available studies is limited, and more research is needed to expand this recommendation. Specifically, additional trials should provide information on adherence, home based interventions, interaction with pharmacological treatments, functional outcomes measures relevant to exercise treatment in these patients, and long term effects. At present, doctors should recommend exercise to all patients with mild/moderate disease. Further study should be encouraged and exercise should be continued to be recommended as a mainstay of non-pharmacological treatment of osteoarthritis of the knee.     

Which medications are safe and effective for improving sleep at high altitude?

Given the well-established problems with sleep at high altitude, it is not uncommon for people planning trips to the mountains to seek advice from clinicians regarding pharmacologic options for improving sleep during their trip. This review article considers the various medications that have been studied for this purpose at high altitude with an emphasis on both their efficacy and safety. The available data support the use of either acetazolamide, temazepam, zolpidem or zaleplon in this environment. Other agents commonly used at sea-level such as eszopiclone and diphenhydramine have not been studied at high altitude but are likely safe to use given their mechanism of action and known side effects. Limited evidence suggests diazepam may cause hypoventilation at high altitude and its use in this environment should be discouraged. Insufficient data exist to determine which agent is most effective at altitude nor do we know whether combination therapy with acetazolamide and a hypnotic agent offers any benefits over monotherapy.     

How effective is an evidence-based exercise intervention in individuals with patellofemoral pain?

ObjectivesGuidelines for a comprehensive rehabilitation programme for patellofemoral pain (PFP) have been developed by international experts. The aim of this study was to analyse the effect of such a rehabilitative exercise programme on pain, function, kinesiophobia, running biomechanics, quadriceps strength and quadriceps muscle inhibition in individuals with PFP.DesignObservational study.SettingClinical environment.ParticipantsTwenty-seven participants with PFP.Main outcome measuresSymptoms [numeric pain rating scale (NPRS)and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS)], function measured by using the KUJALA scale and KOOS, kinesiophobia measured by using the Tampa scale, three-dimensional biomechanical running data, quadriceps isometric, concentric and eccentric strength and arthrogenic muscle inhibition (AMI) were acquired before and after the six-week exercise programme.ResultsAlthough pain did not significantly improve all patients were pain-free after the six-week exercise programme (NPRS: p = 0.074). Function, kinesiophobia and quadriceps AMI improved significantly after the six-week exercise programme (KUJALA: p = 0.001, KOOS: p = 0.0001, Tampa: p = 0.017, AMI: p = 0.018). Running biomechanics during stance phase did not change after the exercise intervention. Quadriceps strength was not different after the six-week exercise programme (isometric: p = 0.992, concentric: p = 0.075, eccentric: p = 0.351).ConclusionThe results of this study demonstrate that the current exercise recommendations can improve function and kinesiophobia and reduce pain and AMI in individuals with PFP. There is a need for reconsideration of the current exercise guidelines in stronger individuals with PFP.     

Thinness and weight loss: beneficial or detrimental to longevity?

This review examined the hypotheses that 1) low body mass index (BMI) is optimal for longevity and 2) weight loss reduces mortality rates. The preponderance of epidemiological evidence fails to support either of these hypotheses. Indeed, a number of studies show that thinness and weight loss (regardless of initial BMI) are associated with increased mortality rates. These findings cannot be attributed to smoking status or to weight loss resulting from subclinical disease. The effect of intentional weight loss on mortality rates depends upon health status. For overweight individuals in good health, there is no compelling evidence to show that mortality rates are reduced with weight loss. Even among overweight persons with one or more obesity-related health conditions, specific weight loss recommendations may be unnecessary: 1) the reduction in mortality rate associated with intentional weight loss is independent of the amount of weight loss, 2) the reductions in all-cause mortality rate associated with increased physical activity and fitness (23-44%), independent of changes in body weight, are greater than that reported for intentional weight loss (approximately 20%), and 3) many obesity-related health conditions (e.g., hypertension, dyslipidemias, insulin resistance, glucose intolerance) can be ameliorated independently of weight loss. In view of the potential risks associated with weight loss and weight cycling, it is suggested that public health may be better served by placing greater emphasis on lifestyle changes and less attention to weight loss per se.     

Whole body vibration exercise: are vibrations good for you?

Whole body vibration has been recently proposed as an exercise intervention because of its potential for increasing force generating capacity in the lower limbs. Its recent popularity is due to the combined effects on the neuromuscular and neuroendocrine systems. Preliminary results seem to recommend vibration exercise as a therapeutic approach for sarcopenia and possibly osteoporosis. This review analyses state of the art whole body vibration exercise techniques, suggesting reasons why vibration may be an effective stimulus for human muscles and providing the rationale for future studies.     

Vitamin E supplementation and endurance exercise: are there benefits?

It has been widely noted that vitamin E shows numerous beneficial effects through and beyond its antioxidative properties; consequently, vitamin E is expected to prevent degenerative diseases. In the field of sports medicine, many studies dealing with vitamin E have been conducted originally from the point of view of its effects on physical performance. Although some earlier studies indicated that vitamin E supplementation could improve physical performance, defects in the study design or statistical analysis were pointed out at a later time. The majority of subsequent well controlled studies have reported no significant effect on physical performance from vitamin E supplementation. Recent studies suggest that endurance exercise may promote free radical generation in the body, and vitamin E may play an important role in preventing the free radical damage associated with endurance exercise. Although there is evidence of free radical involvement in exercise-induced muscle injury, vitamin E supplementation might not be expected to prevent muscle damage caused by exercise in humans without a vitamin E deficiency. Since it is still unclear whether exercise induces lipid peroxidation in the human body, the beneficial effect of vitamin E supplementation on exercise-induced lipid peroxidation has not yet been established. However, it is proposed that as a result of exercise vitamin E may be mobilised from store tissues and redistributed in the body to prevent oxidative damage. Therefore, we are convinced that vitamin E contributes to preventing exercise-induced lipid peroxidation. It has also been indicated that strenuous endurance exercise may enhance the production of oxidised low density lipoprotein (LDL), which plays a key role in the initiation and progression of atherosclerosis. It is also suggested that this enhanced production of oxidised LDL could be reduced if a higher vitamin E status is maintained. Supplementation with 100 to 200mg of vitamin E daily can be recommended for all endurance athletes to prevent exercise-induced oxidative damage and to reap the full health benefits of exercise.     

Patterns of weight loss and regain in wrestlers: has the tradition changed?

To assess current weight loss practices in wrestlers, 63 college wrestlers and 368 high school wrestlers completed a questionnaire that examined the frequency and magnitude of weight loss, weight control methods, emotions associated with weight loss, dieting patterns, and preoccupation with food. Clear patterns emerged showing frequent, rapid, and large weight loss and regain cycles. Of the college wrestlers, 41% reported weight fluctuations of 5.0-9.1 kg each week of the season. For the high school wrestlers, 23% lost 2.7-4.5 kg weekly. In the college cohort, 35% lost 0.5-4.5 kg over 100 times in their life, and 22% had lost 5.0-9.1 kg between 21 and 50 times in their life. Of the high school wrestlers, 42% had already lost 5.0-9.1 kg 1-5 times in their life. A variety of aggressive methods wer used to lose weight including dehydration, food restriction, fasting, and, for a few, vomiting, laxatives, and diuretics. "Making weight" was associated with fatigue, anger, and anxiety. Thirty to forty percent of the wrestlers, at both the high school and college level, reported being preoccupied with food and eating out of control after a match. The tradition of "making weight" still appears to be integral to wrestling. The potential physiological, psychological, and health consequences of these practices merit further attention.     

How effective are lead-rubber aprons in protecting radiosensitive organs from secondary ionizing radiation?

IntroductionThe purpose of this experiment was to explore the direction of scattered secondary ionizing radiation to a patient. A left lateral radiographic examination of the elbow was deemed appropriate due to its close proximity to radiosensitive organs and record dose limiting opportunities upon wearing a lead-rubber apron.MethodsAn anthropomorphic phantom and lead-rubber apron (Pb 0.35 mm) was used with a 15 cc ionization chamber (model 10,100 AT TRIAD) to measure scattered radiation to radiosensitive organs. Dose readings were recorded before and after in order to quantify dose reduction. Pearson's correlation, linear regression, t-test and one way analysis of variance (ANOVA) statistics were used to affirm how likely dose limitation was attributed to chance (p < 0.05).ResultsThe lead-rubber apron offered dose reduction to most radiosensitive organs. Notably, ionizing radiation was significantly reduced to the left breast 0.0083 μGy (98%), right breast 0.0000 μGy (99.9%) and spleen 0.0262 μGy (99.9%). No empirical benefit was recorded for testes and ovaries. Interestingly, the thyroid recorded an increase in dose (0.1733 μGy; p = 0.01). This was later mitigated using a thyroid collar but identifies increased stochastic risks if lead-aprons are worn alone. Scattered radiation was also reduced to both eyes, which were not directly covered.ConclusionLead-rubber aprons are generally utilized to limit ionizing radiation, yet this article offers insight whereby increases to ionizing radiation to the thyroid are plausible when wearing a lead-rubber apron alone. Whilst these findings cannot be generalized to other radiographic examinations it provides insight into a potential increase risk of scatter to a radiosensitive organ.Implications for practiceThis paper has implications because it identifies that lead-rubber has an impact on scattered ionizing radiation to radiosensitive organs for a lateral elbow examination. Further, it identifies the potential for ionizing radiation to be increased to the thyroid upon wearing a lead-rubber apron alone.     

How does exercise affect bone development during growth?

It is increasingly accepted that osteoporosis is a paediatric issue. The prepubertal human skeleton is quite sensitive to the mechanical stimulation elicited by physical activity. To achieve the benefits for bone deriving from physical activity, it is not necessary to perform high volumes of exercise, since a notable osteogenic effect may be achieved with just 3 hours of participation in sports. Physical activity or participation in sport should start at prepubertal ages and should be maintained through the pubertal development to obtain the maximal peak bone mass potentially achievable. Starting physical activity prior to the pubertal growth spurt stimulates both bone and skeletal muscle hypertrophy to a greater degree than observed with normal growth in non-physically active children. High strain-eliciting sport like gymnastics, or participation in sports or weight-bearing physical activities like football or handball, are strongly recommended to increase the peak bone mass. Moreover, the increase in lean mass is the most important predictor for bone mineral mass accrual during prepubertal growth throughout the population. Since skeletal muscle is the primary component of lean mass, participation in sport could have not only a direct osteogenic effect, but also an indirect effect by increasing muscle mass and hence the tensions generated on bones during prepubertal years.     

Is vibration exercise a useful addition to a weight management program?

Vibration exercise (VbX) has received a lot of attention as an exercise modality, which evokes muscular work and elevates metabolic rate that could be a potential method for weight reduction. Popular press has purported that VbX is quick and convenient, and 10 min of VbX is equivalent to 1 h of traditional exercise, where it has been marketed as the new weight‐loss and body toning workout. However, research studies have shown that muscle activation occurs but the energy demand in response to VbX is quite low, where exhaustive VbX reported a metabolic demand of 23 mL/kg/min compared with 44 mL/kg/min from an exhaustive cycle test. Different vibration frequencies with varying amplitudes and loads have been tested, but only small increases in metabolic rate have been reported. Based on these findings, it has been indirectly calculated that a VbX session of 26 Hz for three continuous minutes would only incur a loss of ～10.7 g fat/h. Following a 24‐week program of VbX, no observed differences were found in body composition, and following 12 months of VbX, the time to reach peak was significantly higher in conventional exercise compared with VbX. However, one study has reported that percentage body fat decreased by 3.2% after 8 months after VbX in comparison with resistance and control groups that performed no aerobic conditioning. The evidence to date suggests that VbX can increase whole and local oxygen uptake; however, with additional load, high vibration frequency, and/or amplitude, it cannot match the demands of conventional aerobic exercise. Therefore, caution is required when VbX programs are solely used for the purpose of reducing body fat without considering dietary and aerobic conditioning guidelines.     

How anorexic-like are the symptom and personality profiles of aesthetic athletes?

PURPOSE: We tested the hypothesis that aesthetic athletes (AA) have anorexic-like eating attitudes and behaviors, share personality characteristics such as perfectionism and obsessiveness, and are at high risk of eating disorders. METHODS: We compared symptomatology, personality variables typical of anorexia nervosa, and lifetime eating disorder prevalence across four groups of Israeli women: 31 anorexics, 111 AA (mostly dancers), 68 nonaesthetic athletes (NAA), and 248 controls. All participants completed self-report measures of symptomatology, harm avoidance, perfectionism, obsessiveness, self-esteem, and self-rated facial attractiveness and were screened for eating disorders. Those screening positively were interviewed and diagnosed using the structured clinical interview for DSM-IV. RESULTS: Scores of the anorexic women differed from those of the three other groups in the expected direction on all variables. NAA scored similarly to controls, but had greater body satisfaction and less drive for thinness. Surprisingly, the AA did not differ from control women on any self-report measure. However, significantly more AA (11.7%) than NAA (5.8%) and controls (4.4%) had a lifetime diagnosis of eating disorder not otherwise specified (EDNOS). The eating attitudes and behavior of the 13 AA with a lifetime history of EDNOS fell intermediately between the anorexic women and the controls, whereas their personality profile resembled that of controls. CONCLUSIONS: Being a nonaesthetic female athlete in Israel appears to promote body esteem and offer some protection from a preoccupation with dieting. AA also appear to enjoy excellent psychological health; however, a subgroup has EDNOS and appears not to receive appropriate treatment for it. These results lend credibility to the existence of the diagnostic entity of anorexia athletica, proposed to be a subclinical, environmentally influenced eating disorder with a favorable prognosis.