Five things that happen to your body in space

First paragraph: Tim Peake is the first official British astronaut to walk in space. The former Army Air Corps officer has spent a month in space, after blasting off on a Russian Soyuz rocket to the International Space Station on December 15 last year, but the spacewalk will doubtless be his most gruelling test.https://theconversation.com/five-things-that-happen-to-your-body-in-space-5294

Theoretical Guidance on the Determinants of Success in Agricultural Marketing and Production Clubs

Institutional and Behavioral Economics, Marketing,

Skeletal muscle wasting with disuse atrophy is multi-dimensional: the response and interaction of myonuclei, satellite cells and signaling pathways

Maintenance of skeletal muscle is essential for health and survival. There are marked losses of skeletal muscle mass as well as strength and physiological function under conditions of low mechanical load, such as space flight, as well as ground based models such as bed rest, immobilization, disuse, and various animal models. Disuse atrophy is caused by mechanical unloading of muscle and this leads to reduced muscle mass without fiber attrition. Skeletal muscle stem cells (satellite cells) and myonuclei are integrally involved in skeletal muscle responses to environmental changes that induce atrophy. Myonuclear domain size is influenced differently in fast and slow twitch muscle, but also by different models of muscle wasting, a factor that is not yet understood. Although the myonuclear domain is 3-dimensional this is rarely considered. Apoptosis as a mechanism for myonuclear loss with atrophy is controversial, whereas cell death of satellite cells has not been considered. Molecular signals such as myostatin/SMAD pathway, MAFbx, and MuRF1 E3 ligases of the ubiquitin proteasome pathway and IGF1-AKT-mTOR pathway are 3 distinctly different contributors to skeletal muscle protein adaptation to disuse. Molecular signaling pathways activated in muscle fibers by disuse are rarely considered within satellite cells themselves despite similar exposure to unloading or low mechanical load. These molecular pathways interact with each other during atrophy and also when various interventions are applied that could alleviate atrophy. Re-applying mechanical load is an obvious method to restore muscle mass, however how nutrient supplementation (e.g., amino acids) may further enhance recovery (or reduce atrophy despite unloading or ageing) is currently of great interest. Satellite cells are particularly responsive to myostatin and to growth factors. Recently, the hibernating squirrel has been identified as an innovative model to study resistance to atrophy

Interactions of aging, overload, and creatine supplementation in rat plantaris muscle

Attenuation of age-related sarcopenia by creatine supplementation has been equivocal. In this study, plantaris muscles of young (Y; 5m) and aging (A; 24m) Fisher 344 rats underwent four weeks of either control (C), creatine supplementation (Cr), surgical overload (O), or overload plus creatine (OCr). Creatine alone had no effect on muscle fiber cross-sectional area (CSA) or heat shock protein (HSP70) and increased myonuclear domain (MND) only in young rats. Overload increased CSA and HSP70 content in I and IIA fibers, regardless of age, and MND in IIA fibers of YO rats. CSA and MND increased in all fast fibers of YOCr, and CSA increased in I and IIA fibers of AOCr. OCR did not alter HSP70, regardless of age. MND did not change in aging rats, regardless of treatment. These data indicate creatine alone had no significant effect. Creatine with overload produced no additional hypertrophy relative to overload alone and attenuated overload-induced HSP70 expression

Prevention of Skeletal Muscle Wasting: Disuse Atrophy and Sarcopenia

First paragraph: Skeletal muscle plays a considerable role in health and disease. Muscle mass is essential for health and survival and plays a major role in mobility as well as morbidity and mortality. There is continual synthesis and degradation of proteins as part of normal metabolism and homeostasis. Equally remarkable, is the characteristic of plasticity allowing muscle to change and adapt depending on the stimuli and load placed upon it

When kids run for 15 minutes in school every day, here’s what happens to their health

First paragraph: If you haven’t heard of the Daily Mile yet, your time has come. Now taking place in 3,600 primary schools each day in 35 countries around the world, it takes children outside during normal lesson time to run or walk laps of the playground for 15 minutes. The ones who run cover around a mile each day. The initiative has an endearing back story. It was developed six years ago by St Ninians Primary School in Stirling in central Scotland after children and teachers felt the pupils needed to be fitter

Myostatin levels in skeletal muscle of hibernating ground squirrels

Myostatin, a negative regulator of muscle mass, is elevated during disuse and starvation. Mammalian hibernation presents a unique scenario, where animals are hypocaloric and in torpor, but the extent of muscle protein loss is minimized. We hypothesized that myostatin expression, which is usually increased early in disuse and under hypocaloric conditions, could be suppressed in this unique model. Skeletal muscle was collected from thirteen-lined ground squirrels, Spermophilus tridecemlineatus, at six time points during hibernation: control euthermic (CON); entrance into hibernation (ENT), body temperature (Tb) falling; early hibernation (EHib), stable Tb in torpor for 24 h; late hibernation (LHib), stable Tb in torpor for 3 days; early arousal (EAr), Tb rising; and arousal (AR), Tb restored to 34-37°C for about 18 h. There was no significant increase of myostatin during ENT, EHib or LHib. Unexpectedly, there were approximately sixfold increases in myostatin protein levels as squirrels arose from torpor. The elevation during EAr remained high in AR, which represented an interbout time period. Mechanisms that could release the suppression or promote increased levels of myostatin were assessed. SMAD2 and phosphorylated SMAD2 were increased during EHib, but only the phosphorylated SMAD2 during AR mirrored increases in myostatin. Follistatin, a negative regulator of myostatin, did not follow the same time course as myostatin or its signaling pathway, indicating more control of myostatin at the signaling level. However, SMAD7, an inhibitory SMAD, did not appear to play a significant role during deep hibernation. Hibernation is an excellent natural model to study factors involved in the endogenous intracellular mechanisms controlling myostatin

A citizen science study of short physical activity breaks at school:Improvements in cognition and wellbeing with self-paced activity

Background School-based physical activity and running programmes, such as The Daily Mile™, are increasing in popularity globally. The aim of this research was to examine the acute impact of such classroom physical activity breaks on cognition and affective wellbeing. Methods A total of 5463 school pupils from 332 schools took part in a citizen science project with a repeated measures design. They completed tasks of cognition (inhibition, verbal, and visuo-spatial working memory) and the Children’s Feeling Scale and Felt Arousal Scale before and after three different outdoor activities: a classroom break of 15 min of self-paced activity, a near maximal exhaustion activity (the bleep test), and a no-exercise control group where pupils sat or stood outside. Wellbeing and fitness were examined as mediators of the relationship between outdoor activity and cognition. Results Fifteen minutes of self-paced outdoor activity was beneficial for pupils’ cognition and wellbeing in comparison to both other activities (Cohen’s d effect sizes ranging from 0.04 to 0.22; small). The relationship with cognition was not mediated by participants’ fitness level and was only partially mediated by wellbeing. Change scores for alertness were higher after the bleep test compared to the control activity but similar for all other outcomes. Conclusions Taking a break from the classroom to complete 15 min of self-paced physical activity should be considered a worthwhile activity by class teachers, school management, and policymakers. Additionally, more intense physical activity should not be considered to be detrimental

The impact of the Daily Mile on Primary School Children

The Daily Mile is a physical activity programme through which primary-aged children run or walk for 15 minutes every day, at a self-selected pace. First developed at St Ninians Primary, Stirling, in 2012, the initiative has grown in popularity nationally and internationally, initially driven by anecdotally reported benefits of participation. The Scottish Government’s Programme for Scotland 2017-18, A Nation with Ambition, sets out plans for Scotland to become the world’s first ‘Daily Mile nation’. In August 2017, Ministers wrote to schools, nurseries, colleges and universities urging them to take up the challenge. The concept is easily adaptable in a nation facing significant public health challenges. As outlined in the Scottish Government’s policy paper Public Health Priorities for Scotland (2018), two thirds of adults in Scotland are overweight, with the total economic cost of obesity to Scotland estimated to be as much as £4.6 billion. The paper states that action on Scotland’s public health priorities will be evidence-led, applying public health expertise, data and intelligence, developing new solutions to drive a healthier nation. This briefing - drawing on three studies led by University of Stirling researchers - has the potential to inform the rollout of the Daily Mile in Scotland, including a widening of the initiative beyond the education sector

Influence of exercise on the metabolic profile caused by 28 days of bed rest with energy deficit and amino acid supplementation in healthy men

Objective: Muscle loss and metabolic changes occur with disuse [i.e. bed rest (BR)]. We hypothesized that BR would lead to a metabolically unhealthy profile defined by: increased circulating tumor necrosis factor (TNF)-α, decreased circulating insulin-like-growth-factor (IGF)-1, decreased HDL-cholesterol, and decreased muscle density (MD; measured by mid-thigh computerized tomography).  Methods: We investigated the metabolic profile after 28 days of BR with 8±6% energy deficit in male individuals (30-55 years) randomized to resistance exercise with amino acid supplementation (RT, n=24) or amino acid supplementation alone (EAA, n=7). Upper and lower body exercises were performed in the horizontal position. Blood samples were taken at baseline, after 28 days of BR and 14 days of recovery.  Results: We found a shift toward a metabolically unfavourable profile after BR [compared to baseline (BLN)] in both groups as shown by decreased HDL-cholesterol levels (EAA: BLN: 39±4 vs. BR: 32±2 mg/dL, RT: BLN: 39±1 vs. BR: 32±1 mg/dL; p<0.001) and Low MD (EAA: BLN: 27±4 vs. BR: 22±3 cm2, RT: BLN: 28±2 vs. BR: 23±2 cm2; p<0.001). A healthier metabolic profile was maintained with exercise, including NormalMD (EAA: BLN: 124±6 vs. BR: 110±5 cm2, RT: BLN: 132±3 vs. BR: 131±4 cm2; p<0.001, time-by-group); although, exercise did not completely alleviate the unfavourable metabolic changes seen with BR. Interestingly, both groups had increased plasma IGF-1 levels (EAA: BLN:168±22 vs. BR 213±20 ng/mL, RT: BLN:180±10 vs. BR: 219±13 ng/mL; p<0.001) and neither group showed TNFα changes (p>0.05).  Conclusions: We conclude that RT can be incorporated to potentially offset the metabolic complications of BR