Physical exercise minimizes the toxic triad for cancer: Physical inactivity, low fitness, and obesity

The so-called toxic triad of factors linked to cancer, namely obesity, poor cardiorespiratory fitness and physical inactivity, increase the risk of cancer and, when cancer is present, worsen its prognosis. Thus, obesity and a sedentary lifestyle have been linked to an elevated cancer risk whereas regular physical exercise and good cardiorespiratory function (CRF) diminish this risk. Despite genetic risk factors, there is evidence to show that some lifestyle modifications are capable of reducing the incidence of cancer and its associated morbidity and mortality. Regular physical exercise targeted at maintaining body weight within healthy limits and improving CRF will reduce a person's cancer risk and, once diagnosed, will also improve its prognosis, reducing mortality and the risk of disease recurrence through similar effects. In this review, we describe how physical activity can be used as a pleiotropic, coadjuvant tool to minimize the toxic triad for cancer and update the mechanisms proposed to date for the effects observed.

The importance of physical fitness in the performance of adequate cardiopulmonary resuscitation

The aim of the present investigation was to evaluate the influence of the physical fitness of a cardiopulmonary resuscitation (CPR) provider on the performance of and physiologic response to CPR. To this end, comparisons were made of sedentary and physically active subjects in terms of CPR performance and physiologic variables. Two study groups were established: group P (n = 14), composed of sedentary, professional CPR rescuers (mean [± SD]; age, 34 ± 6 years; V̇O2max, 32.5 ± 5.5 mL/kg/min), and group Ex (n = 14), composed of physically active, nonexperienced subjects (age, 34 ± 6 years; V̇O2max, 44.5 ± 8.5 mL/kg/min). Each subject was required to perform an 18-min CPR session, which involved manual external cardiac compressions (ECCs) on an electronic teaching mannequin following accepted standard CPR guidelines. Subjects' gas exchange parameters and heart rates (HRs) were monitored throughout the trial. Variables indicating the adequacy of the ECCs (ECC depth and the percentage of incorrect compressions and hand placements) also were determined. Overall CPR performance was similar in both groups. The indicators of ECC adequacy fell within accepted limits (ie, an ECC depth between 38 and 51 mm). However, fatigue prevented four subjects from group P from completing the trial. In contrast, the physiologic responses to CPR differed between groups. The indicators of the intensity of effort during the trial, such as HR or percentage of maximum oxygen uptake (V̇O2max) were higher in group P subjects than group Ex subjects, respectively (HRs at the end of the trial, 139 ± 22 vs 115 ± 17 beats/min, p < 0.01; percentage of V̇O2max after 12 min of CPR, 46.7 ± 9.7% vs 37.2 ± 10.4%, p < 0,05). These results suggest that a certain level of physical fitness may be beneficial to CPR providers to ensure the adequacy of chest compressions performed during relatively long periods of cardiac arrest.

High body mass index is not a barrier to physical activity: Analysis of international rugby players' anthropometric data

Recent data indicate that levels of overweight and obesity are increasing at an alarming rate throughout the world. At a population level (and commonly to assess individual health risk), the prevalence of overweight and obesity is calculated using cut-offs of the Body Mass Index (BMI) derived from height and weight. Similarly, the BMI is also used to classify individuals and to provide a notional indication of potential health risk. It is likely that epidemiologic surveys that are reliant on BMI as a measure of adiposity will overestimate the number of individuals in the overweight (and slightly obese) categories. This tendency to misclassify individuals may be more pronounced in athletic populations or groups in which the proportion of more active individuals is higher. This differential is most pronounced in sports where it is advantageous to have a high BMI (but not necessarily high fatness). To illustrate this point we calculated the BMIs of international professional rugby players from the four teams involved in the semi-finals of the 2003 Rugby Union World Cup. According to the World Health Organisation (WHO) cut-offs for BMI, approximately 65% of the players were classified as overweight and approximately 25% as obese. These findings demonstrate that a high BMI is commonplace (and a potentially desirable attribute for sport performance) in professional rugby players. An unanswered question is what proportion of the wider population, classified as overweight (or obese) according to the BMI, is misclassified according to both fatness and health risk? It is evident that being overweight should not be an obstacle to a physically active lifestyle. Similarly, a reliance on BMI alone may misclassify a number of individuals who might otherwise have been automatically considered fat and/or unfit.