Estimating trends in dietary intake data is integral to informing national nutrition policy and monitoring progress towards dietary guidelines. Dietary intake of sugars is a controversial public health issue and guidance in relation to recommended intakes is particularly inconsistent. Published data relating to trends in sugars intake are relatively sparse. The purpose of the present review was to collate and review data from national nutrition surveys to examine changes and trends in dietary sugars intake. Only thirteen countries (all in the developed world) appear to report estimates of sugars intake from national nutrition surveys at more than one point in time. Definitions of dietary sugars that were used include 'total sugars', 'non-milk extrinsic sugars', 'added sugars', sucrose' and 'mono-and disaccharides'. This variability in terminology across countries meant that comparisons were limited to within countries. Hence trends in dietary sugars intake were examined by country for the whole population (where data permitted), and for specific or combined age and sex subpopulations. Findings indicate that in the majority of population comparisons, estimated dietary sugars intake is either stable or decreasing in both absolute (g/d) and relative (% energy) terms. An increase in sugars intake was observed in few countries and only in specific subpopulations. In conclusion, the findings from the present review suggest that, in the main, dietary sugars intake are decreasing or stable. A consistent approach to estimation of dietary sugars intake from national nutrition surveys is required if more valid estimates of changes in dietary sugars intakes are required in the future.

an all-out pacing strategy was apparent for at least up to 15 s, with indicators of dampened power in both 30 and 45 s sprints. Reduced power at the start of all-out long-duration sprints support a central control of at least initial pacing strategy.

An activity profile of competitive 3 × 2-min novice-level amateur boxing was created based on video footage and postbout blood [La] in 32 male boxers (mean ± SD) age 19.3 ± 1.4 y, body mass 62.6 ± 4.1 kg. Winners landed 18 ± 11 more punches than losers by applying more lead-hand punches in round 1 (34.2 ± 10.9 vs 26.5 ± 9.4), total punches to the head (121.3 ± 10.2 vs 96.0 ± 9.8), and block and counterpunch combinations (2.8 ± 1.1 vs. 0.1 ± 0.2) over all 3 rounds and punching combinations (44.3 ± 6.4 vs 28.8 ± 6.7) in rounds 1 and 3 (all P < .05). In 16 boxers, peak postbout blood [La] was 11.8 ± 1.6 mmol/L irrespective of winning or losing. The results suggest that landing punches requires the ability to maintain a high frequency of attacking movements, in particular the lead-hand straight punch to the head together with punching combinations. Defensive movements must initiate a counterattack. Postbout blood [La] suggests that boxers must be able to tolerate a lactate production rate of 1.8 mmol · L−1 · min−1 and maintain skillful techniques at a sufficient activity rate.

We systematically reviewed interventions substituting sucrose for other macronutrients in apparently healthy adults to assess impact on cardiometabolic risk indicators. Multiple databases were searched to January 2012 and abstracts assessed by 2 reviewers. Twenty-five studies (29 papers) met inclusion criteria but varied in quality and duration. Weaknesses included small subject numbers, unclear reporting of allocation, unusual dietary regimes, differences in energy intake, fat composition or fibre between conditions, unhealthy subjects, heterogeneity of results, and selective reporting. Insufficient data were available to draw reliable conclusions except with regard to the substitution of sucrose for starch, where effects on plasma lipids were inconsistent, mostly explicable by other factors, or nonsignificant. Based on fewer studies, there was little evidence for significant effects on plasma glucose or insulin. Sucrose substitution for starch up to 25% energy does not appear to have adverse effects on cardiometabolic risk indicators in apparently healthy adults. Furthermore, there is no consistent evidence that restricting sucrose in an isoenergetic diet would affect risk indicators, except perhaps in people with certain preexisting metabolic abnormalities. Larger, high-quality studies, lasting several months and studying a wider range of outcomes, are needed in order to provide evidence on which to base public health initiatives.

Human bone blood flow, mean blood speed and the number of moving red blood cells were assessed (in arbitrary units), as a function of time, during one cardiac cycle. The measurements were obtained non-invasively on five volunteers by laser-Doppler flowmetry at large interoptode spacing. The investigated bones included: patella, clavicle, tibial diaphysis and tibial malleolus. As hypothesized, we found that in all bones the number of moving cells remains constant during cardiac cycles. Therefore, we concluded that the pulsatile nature of blood flow must be completely determined by the mean blood speed and not by changes in blood volume (vessels dilation). Based on these results, it is finally demonstrated using a mathematical model (derived from the radiative transport theory) that photoplethysmographic (PPG) pulsations observed by others in the literature, cannot be generated by oscillations in blood oxygen saturation, which is physiologically linked to blood speed. In fact, possible oxygen saturation changes during pulsations decrease the amplitude of PPG pulsations due to specific features of the PPG light source. It is shown that a variation in blood oxygen saturation of 3% may induce a negative change of ∼1% in the PPG signal. It is concluded that PPG pulsations are determined by periodic 'positive' changes of the reduced scattering coefficient of the tissue and/or the absorption coefficient at constant blood volume. No explicit experimental PPG measurements have been performed. As a by-product of this study, an estimation of the arterial pulse wave velocity obtained from the analysis of the blood flow pulsations give a value of 7.8 m s −1 (95% confidence interval of the sample mean distribution: [6.7, 9.5] m s −1 ), which is perfectly compatible with data in the literature. We hope that this note will contribute to

Warm-up is generally considered beneficial for performance, although the reduction in anaerobic glycolytic metabolism may be detrimental to sprinting. This study examined the effect of warm-up intensity on metabolism and performance in sprint cycling. The mean power was determined during a 1-min sprint on 11 trained males preceded by easy (WE), moderate (WM) or hard (WH) warm-up and a 10-min recovery. Aerobic, anaerobic glycolytic and phosphocreatine energy provision to the sprint was determined from oxygen uptake and lactate production. Blood lactate concentration before the sprint increased with the warm-up intensity (WE: 1.2±0.3; WM: 2.0±0.3; WH: 4.2±0.9 mmol/L, P<0.001), with WH reducing the increase in lactate production during exercise vs WE (WE: 11.6±1.6; WM: 10.9±1.9; WH: 9.2±1.4 mmol/L, P<0.05). Despite the lower relative anaerobic glycolytic energy provision in WH vs WE (WH: 38±5; WM: 36±6; WE: 34±3%, P<0.05), the mean power was unaffected (WE: 516±28; WM: 521±26; WH: 526±34 W, P>0.05) due to increased oxygen uptake in WH during the sprint (WE: 3.2±0.4; WM: 3.3±0.3; WH: 3.4±0.4 liters, P<0.05). This study supports a warm-up-induced reduction in glycolytic rate, although sprint performance, at least of a long duration, may be maintained due to increased oxygen utilization.

To investigate the effects of warm-up intensity on all-out sprint cycling performance, muscle oxygenation and metabolism, 8 trained male cyclists/triathletes undertook a 30-s sprint cycling test preceded by moderate, heavy or severe warm up and 10-min recovery. Muscle oxygenation was measured by near-infrared spectroscopy, with deoxyhaemoglobin ([HHb]) during the sprint analysed with monoexponential models with time delay. Aerobic, anaerobic-glycolytic and phosphocreatine energy provision to the sprint were estimated from oxygen uptake and lactate production. Immediately prior to the sprint, blood [lactate] was different for each warm up and higher than resting for the heavy and severe warm ups (mod. 0.94 ± 0.36, heavy 1.92 ± 0.64, severe 4.37 ± 0.93 mmol l(-1) P < 0.05), although muscle oxygenation was equally raised above rest. Mean power during the sprint was lower following severe compared to moderate warm up (mod. 672 ± 54, heavy 666 ± 56, severe 655 ± 59 W, P < 0.05). The [HHb] kinetics during the sprint were not different among conditions, although the time delay before [HHb] increased was shorter for severe versus moderate warm up (mod. 5.8 ± 0.6, heavy 5.6 ± 0.9, severe 5.2 ± 0.7 s, P < 0.05). The severe warm up was without effect on estimated aerobic metabolism, but increased estimated phosphocreatine hydrolysis, the latter unable to compensate for the reduction in estimated anaerobic-glycolytic metabolism. It appears that despite all warm ups equally increasing muscle oxygenation, and indicators of marginally faster oxygen utilisation at the start of exercise following a severe-intensity warm up, other energy sources may not be able to fully compensate for a reduced glycolytic rate in sprint exercise with potential detrimental effects on performance.

The consumption of carbohydrate before, during, and after exercise is a central feature of the athlete's diet, particularly those competing in endurance sports. Sucrose is a carbohydrate present within the diets of athletes. Whether sucrose, by virtue of its component monosaccharides glucose and fructose, exerts a meaningful advantage for athletes over other carbohydrate types or blends is unclear. This narrative reviews the literature on the influence of sucrose, relative to other carbohydrate types, on exercise performance or the metabolic factors that may underpin exercise performance. Inference from the research to date suggests that sucrose appears to be as effective as other highly metabolizable carbohydrates (e.g., glucose, glucose polymers) in providing an exogenous fuel source during endurance exercise, stimulating the synthesis of liver and muscle glycogen during exercise recovery and improving endurance exercise performance. Nonetheless, gaps exist in our understanding of the metabolic and performance consequences of sucrose ingestion before, during, and after exercise relative to other carbohydrate types or blends, particularly when more aggressive carbohydrate intake strategies are adopted. While further research is recommended and discussed in this review, based on the currently available scientific literature it would seem that sucrose should continue to be regarded as one of a variety of options available to help athletes achieve their specific carbohydrate-intake goals.