Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit

The myofibrillar protein synthesis (MPS) response to resistance exercise (REX) and protein ingestion during energy deficit (ED) is unknown. We determined, in young men (n=8) and women (n=7), protein signaling, resting post-absorptive MPS during energy balance [EB: 45 kcal∙(kg FFM∙d)-1] and after 5d of ED [30 kcal∙(kg FFM∙d)-1] as well as MPS while in ED after acute REX in the fasted state and with the ingestion of whey protein (15 and 30 g). Post-absorptive rates of MPS were 27% lower in ED than EB (P<0.001), but REX stimulated MPS to rates equal to EB. Ingestion of 15 and 30 g of protein after REX in ED increased MPS ~16 and ~34% above resting EB, (P<0.02). p70 S6Kthr389 phosphorylation increased above EB only with combined exercise and protein intake (~2-7 fold; P<0.05). In conclusion, short-term ED reduces post-absorptive MPS, however, a bout of REX in ED restores MPS to values observed at rest in EB. The ingestion of protein after REX further increases MPS above resting EB in a dose-dependent manner. We conclude that combining REX with increased protein availability after exercise enhances rates of skeletal muscle protein synthesis during short term ED and could, in the long term, preserve muscle mass.

Cold water immersion enhances recovery of submaximal muscle function after resistance exercise

We investigated the effect of cold water immersion (CWI) on the recovery of muscle function and physiological responses following high-intensity resistance exercise. Using a randomized, cross-over design, 10 physically active men performed high-intensity resistance exercise, followed by one of two recovery interventions: 10 min of cold water immersion at 10°C, or 10 min active recovery (low-intensity cycling). After the recovery interventions, maximal muscle function was assessed after 2 h and 4 h by measuring jump height and isometric squat strength. Submaximal muscle function was assessed after 6 h by measuring the average load lifted during six sets of 10 squats at 80% 1RM. Intramuscular temperature (1 cm) was also recorded, and venous blood samples were analyzed for markers of metabolism, vasoconstriction and muscle damage. CWI did not enhance recovery of maximal muscle function. However, during the final three sets of the submaximal muscle function test, the participants lifted a greater load (p<0.05; 38%; Cohen’s d 1.3) following CWI compared with active recovery. During CWI, muscle temperature decreased 6°C below post-exercise values, and remained below pre-exercise values for another 35 min. Venous blood O2 saturation decreased below pre-exercise values for 1.5 h after CWI. Serum endothelin-1 concentration did not change after CWI, whereas it decreased after active recovery. Plasma myoglobin concentration was lower, whereas plasma interleukin-6 concentration was higher after CWI compared with active recovery. These results suggest that cold water immersion after resistance exercise allow athletes to complete more work during subsequent training sessions, which could enhance long-term training adaptations.

Metabolic and hormonal responses to isoenergetic high-intensity interval exercise and continuous moderate-intensity exercise

This study investigated the effects of high-intensity interval training (HIIT) vs. work-matched moderate-intensity continuous exercise (MOD) on metabolism and counterregulatory stress hormones. In a randomized and counterbalanced order, 10 well-trained male cyclists and triathletes completed a HIIT session [81.6 ± 3.7% maximum oxygen consumption (V̇o2 max); 72.0 ± 3.2% peak power output; 792 ± 95 kJ] and a MOD session (66.7 ± 3.5% V̇o2 max; 48.5 ± 3.1% peak power output; 797 ± 95 kJ). Blood samples were collected before, immediately after, and 1 and 2 h postexercise. Carbohydrate oxidation was higher (P = 0.037; 20%), whereas fat oxidation was lower (P = 0.037; −47%) during HIIT vs. MOD. Immediately after exercise, plasma glucose (P = 0.024; 20%) and lactate (P < 0.01; 5.4×) were higher in HIIT vs. MOD, whereas total serum free fatty acid concentration was not significantly different (P = 0.33). Targeted gas chromatography-mass spectromtery metabolomics analysis identified and quantified 49 metabolites in plasma, among which 11 changed after both HIIT and MOD, 13 changed only after HIIT, and 5 changed only after MOD. Notable changes included substantial increases in tricarboxylic acid intermediates and monounsaturated fatty acids after HIIT and marked decreases in amino acids during recovery from both trials. Plasma adrenocorticotrophic hormone (P = 0.019), cortisol (P < 0.01), and growth hormone (P < 0.01) were all higher immediately after HIIT. Plasma norepinephrine (P = 0.11) and interleukin-6 (P = 0.20) immediately after exercise were not significantly different between trials. Plasma insulin decreased during recovery from both HIIT and MOD (P < 0.01). These data indicate distinct differences in specific metabolites and counterregulatory hormones following HIIT vs. MOD and highlight the value of targeted metabolomic analysis to provide more detailed insights into the metabolic demands of exercise.

Ibuprofen supplementation and its effects on NF-KB activation in skeletal muscle following resistance exercise

Resistance exercise triggers a subclinical inflammatory response that plays a pivotal role in skeletal muscle regeneration. Nuclear factor‐κB (NF‐κB) is a stress signalling transcription factor that regulates acute and chronic states of inflammation. The classical NF‐κB pathway regulates the early activation of post‐exercise inflammation; however there remains scope for this complex transcription factor to play a more detailed role in post‐exercise muscle recovery. Sixteen volunteers completed a bout of lower body resistance exercise with the ingestion of three 400 mg doses of ibuprofen or a placebo control. Muscle biopsy samples were obtained prior to exercise and at 0, 3 and 24 h post‐exercise and analysed for key markers of NF‐κB activity. Phosphorylated p65 protein expression and p65 inflammatory target genes were elevated immediately post‐exercise independent of the two treatments. These changes did not translate to an increase in p65 DNA binding activity. NF‐κB p50 protein expression and NF‐κB p50 binding activity were lower than pre‐exercise at 0 and 3 h post‐exercise, but were elevated at 24 h post‐exercise. These findings provide novel evidence that two distinct NF‐κB pathways are active in skeletal muscle after resistance exercise. The initial wave of activity involving p65 resembles the classical pathway and is associated with the onset of an acute inflammatory response. The second wave of NF‐κB activity comprises the p50 subunit, which has been previously shown to resolve an acute inflammatory program. The current study showed no effect of the ibuprofen treatment on markers of the NF‐κB pathway, however examination of the within group effects of the exercise protocol suggests that this pathway warrants further research.

Altering the redox state of skeletal muscle by glutathione depletion increases the exercise-activation of PGC-1α

We investigated the relationship between mitochondrial biogenesis, cell signalling and antioxidant enzymes by depleting skeletal muscle glutathione with diethyl maleate (DEM) which resulted in a demonstrable increase in oxidative stress during exercise. Animals were divided into six groups: (1) sedentary control rats; (2) sedentary rats treated with DEM; (3) exercise control rats euthanized immediately after exercise; (4) exercise rats + DEM; (5) exercise control rats euthanized 4 h after exercise, and; (6) exercise rats + DEM euthanized 4 h after exercise. Exercising animals ran on the treadmill at a 10% gradient at 20 m/min for the first 30 min. The speed was then increased every 10 min by 1.6 m/min until exhaustion. There was a reduction in total glutathione in the skeletal muscle of DEM treated animals compared to the control animals (P<0.05). Within the control group, total glutathione was higher in the sedentary group compared to after exercise (P<0.05). DEM treatment also significantly increased oxidative stress, as measured by increased plasma F2-isoprostanes (P<0.05). Exercising animals given DEM showed a significantly greater increase in peroxisome proliferator activated receptor γ coactivator-1α(PGC-1α) mRNA compared to the control animals that were exercised (P<0.05). This study provides novel evidence that by reducing the endogenous antioxidant glutathione in skeletal muscle and inducing oxidative stress through exercise, PGC-1α gene expression was augmented. These findings further highlight the important role of exercise induced oxidative stress in the regulation of mitochondrial biogenesis.

Physical and functional implications of aquatic exercise for nursing home residents with dementia

Exercise has reported benefits for those with dementia. In the current study we investigated the feasibility of delivery and the physical and functional benefits of an innovative aquatic exercise program for adults with moderate to severe dementia living in a nursing home aged care facility. Ten adults (88.4 years, inter quartile range 12.3) participated twice weekly for 12 weeks. Anthropometric and grip strength data, and measures of physical function and balance were collected at baseline and post-intervention. Feasibility was assessed by attendance, participation, enjoyment and recruitment. Following exercise, participant's left hand grip strength had improved significantly (p = .017). Small to moderate effect sizes were observed for other measures. A number of delivery challenges emerged, but participant enjoyment, benefits and attendance suggest feasibility. Aquatic exercise shows promise as an intervention among those with dementia who live in a nursing home aged care facility. Greater program investigation is warranted.

A comparison between conductive and infrared devices for measuring mean skin temperature at rest, during exercise in the heat, and recovery

Purpose: Skin temperature assessment has historically been undertaken with conductive devices affixed to the skin. With the development of technology, infrared devices are increasingly utilised in the measurement of skin temperature. Therefore, our purpose was to evaluate the agreement between four skin temperature devices at rest, during exercise in the heat, and recovery. Methods: Mean skin temperature (T̅sk) was assessed in thirty healthy males during 30 min rest (24.0± 1.2°C, 56 ± 8%), 30 min cycle in the heat (38.0 ± 0.5°C, 41 ± 2%), and 45 min recovery(24.0 ± 1.3°C, 56 ± 9%). T̅sk was assessed at four sites using two conductive devices(thermistors, iButtons) and two infrared devices (infrared thermometer, infrared camera). Results: Bland–Altman plots demonstrated mean bias ± limits of agreement between the thermistors and iButtons as follows (rest, exercise, recovery): -0.01 ± 0.04, 0.26 ± 0.85, -0.37 ± 0.98°C; thermistors and infrared thermometer: 0.34 ± 0.44, -0.44 ± 1.23, -1.04 ± 1.75°C; thermistors and infrared camera (rest, recovery): 0.83 ± 0.77, 1.88 ± 1.87°C. Pairwise comparisons of T̅sk found significant differences (p < 0.05) between thermistors and both infrared devices during resting conditions, and significant differences between the thermistors and all other devices tested during exercise in the heat and recovery. Conclusions: These results indicate poor agreement between conductive and infrared devices at rest, during exercise in the heat, and subsequent recovery. Infrared devices may not be suitable for monitoring T̅sk in the presence of, or following, metabolic and environmental induced heat stress.

Pilot study comparing the influence of different types of exercise intervention on the fear of falling in older adults

Background: Individuals who fear falling may restrict themselves from performing certain activities and may increase their risk of falling. Such fear, reflected in the form of falls efficacy, has been measured in only a small number of studies measuring the effectiveness of exercise interventions in the elderly. This may be due to the various types of exercise that can be performed. Hence the effectiveness of exercise on falls efficacy is relatively understudied. Therefore, there is a need to measure falls efficacy as an outcome variable when conducting exercise interventions in the elderly. Methods: A total of 43 elderly community-dwelling volunteers were recruited and randomly allocated to a conventional exercise intervention, a holistic exercise intervention, or a control group. The interventions were performed 2 days per week for 10 weeks. Falls efficacy was measured at baseline and at the completion of the interventions using the Modified Falls Efficacy Scale (MFES). Results: Within group comparisons between baseline and follow-up indicated no significant improvements in falls efficacy, however, the difference for the conventional exercise group approached statistical significance (baseline 8.9 to follow-up 9.3; P = 0.058). Within group comparisons of mean difference MFES scores showed a significant difference between the conventional exercise group and the control group (conventional exercise group 0.4 vs control group −0.6; P < 0.05). Conclusion: Given the lack of significant improvements in falls efficacy found for any of the groups, it cannot be concluded whether a conventional or a holistic exercise intervention is the best approach for improving falls efficacy. It is possible that the characteristics of the exercise interventions including specificity, intensity, frequency and duration need to be manipulated if the purpose is to bring about improvements in falls efficacy.

Prospective ten-month exercise intervention in premenarcheal girls: Positive effects on bone and lean mass

Enhancement of bone mineral acquisition during growth may be a useful preventive strategy against osteoporosis. The aim of this study was to explore the lean mass, strength, and bone mineral response to a 10-month, high-impact, strength-building exercise program in 71 premenarcheal girls, aged 9–10 years. Lean body mass, total body (TB), lumbar spine (LS), proximal femur (PF), and femoral neck (FN) bone mineral were measured using the Hologic QDR 2000+ bone densitometer. Strength was assessed using a grip dynamometer and the Cybex isokinetic dynamometer (Cybex II). At baseline, no significant difference in body composition, pubertal development, calcium intake, physical activity, strength, or bone mineral existed between groups. At completion, there were again no differences in height, total body mass, pubertal development, calcium intake, or external physical activity. In contrast, the exercise group gained significantly more lean mass, less body fat content, greater shoulder, knee and grip strength, and greater TB, LS, PF, and FN BMD (exercise: TB 3.5%, LS 4.8%, PF 4.5%, and FN 12.0%) compared with the controls (controls: TB 1.2%, LS 1.2%, PF 1.3%, and FN 1.7%). TB bone mineral content (BMC), LS BMC, PF BMC, FN BMC, LS bone mineral apparent density (BMAD), and FN bone area also increased at a significantly greater rate in the exercise group compared with the controls. In multiple regression analysis, change in lean mass was the primary determinant of TB, FN, PF, and LS BMD accrual. Although a large proportion of bone mineral accrual in the premenarcheal skeleton was related to growth, an osteogenic effect was associated with exercise. These results suggest that high-impact, strength building exercise is beneficial for premenarcheal strength, lean mass gains, and bone mineral acquisition.

An individual-based versus group-based exercise and counselling intervention for improving quality of life in breast cancer survivors. A feasibility and efficacy study

Background Cancer and its treatments produce lingering side-effects that undermine the quality of life (QOL) of survivors. Exercise and psycho-therapies increase QOL among survivors, however, research is needed to identify intervention characteristics most associated with such improvements. Objective This research aimed to assess the feasibility of a 9 week individual or group based exercise and counselling program, and to examine if a group based intervention is as effective at improving the QOL of breast cancer survivors as an individual-based intervention. Methods A three group design was implemented to compare the efficacy of a 9 week individual (IEC n = 12) and group based exercise and counselling (GEC n = 14) intervention to a usual care (UsC n = 10) group on QOL of thirty-six breast cancer survivors. Results Across all groups, 90% of participants completed the interventions, with no adverse effects documented. At the completion of the intervention, there was a significant difference between groups for change in global QOL across time (p < 0.023), with IEC improving significantly more (15.0 points) than the UsC group (1.8 points). The effect size was moderate (0.70). Although the GEC improved QOL by almost 10.0 points, this increase did not reach significance. Both increases were above the minimally important difference of 7–8 points. Conclusion These preliminary results suggest a combined exercise and psychological counseling program is both a feasible and acceptable intervention for breast cancer survivors. Whilst both the individual and group interventions improved QOL above the clinically important difference, only the individual based intervention was significant when compared to UsC.

Higher-intensity exercise results in more sustainable improvements for VO2peak for breast and prostate cancer survivors

Purpose/Objectives: To examine peak volume of oxygen consumption (VO2peak) changes after a high- or low-intensity exercise intervention.
 Design: Experimental trial comparing two randomized intervention groups with control. 
 Setting: An exercise clinic at a university in Australia.
 Sample: 87 prostate cancer survivors (aged 47–80 years) and 72 breast cancer survivors (aged 34–76 years).
 Methods: Participants enrolled in an eight-week exercise intervention (n = 84) or control (n = 75) group. Intervention participants were randomized to low-intensity (n = 44, 60%–65% VO2peak, 50%–65% of one repetition maximum [1RM]) or high-intensity (n = 40, 75%–80% VO2peak, 65%–80% 1RM) exercise groups. Participants in the control group continued usual routines. All participants were assessed at weeks 1 and 10. The intervention groups were reassessed four months postintervention for sustainability. 
 Main Research Variables: VO2peak and self-reported physical activity.
 Findings: Intervention groups improved VO2peak similarly (p = 0.083), and both more than controls (p < 0.001). The high-intensity group maintained VO2peak at follow-up, whereas the low-intensity group regressed (p = 0.021). The low-intensity group minimally changed from baseline to follow-up by 0.5 ml/kg per minute, whereas the high-intensity group significantly improved by 2.2 ml/kg per minute (p = 0.01). Intervention groups always reported similar physical activity levels. 
 Conclusions: Higher-intensity exercise provided more sustainable cardiorespiratory benefits than lower-intensity exercise.
 Implications for Nursing: Survivors need guidance on exercise intensity, because a high volume of low-intensity exercise may not provide sustained health benefits.

An exercise intervention during chemotherapy for women with recurrent ovarian cancer: A feasibility study

Objective: The aim of this study was to determine the feasibility of a combined supervised and home-based exercise intervention during chemotherapy for women with recurrent ovarian cancer. Secondary aims were to determine the impact of physical activity on physical and psychological outcomes and on chemotherapy completion rates. Methods: Women with recurrent ovarian cancer were recruited from 3 oncology outpatient clinics in Sydney and Canberra, Australia. All participants received an individualized exercise program that consisted of 90 minutes or more of low to moderate aerobic, resistance, core stability, and balance exercise per week, for 12 weeks. Feasibility was determined by recruitment rate, retention rate, intervention adherence, and adverse events. Aerobic capacity, muscular strength, fatigue, sleep quality, quality of life, depression, and chemotherapy completion rates were assessed at weeks 0, 12, and 24. Results: Thirty participants were recruited (recruitment rate, 63%), with a retention rate of 70%. Participants averaged 196 ± 138 min · wk of low to moderate physical activity throughout the intervention, with adherence to the program at 81%. There were no adverse events resulting from the exercise intervention. Participants who completed the study displayed significant improvements in quality of life (P = 0.017), fatigue (P = 0.004), mental health (P = 0.007), muscular strength (P = 0.001), and balance (P = 0.003) after the intervention. Participants completing the intervention had a higher relative dose intensity than noncompleters (P = 0.03). Conclusions: A program consisting of low to moderate exercise of 90 min · wk was achieved by two-thirds of women with recurrent ovarian cancer in this study, with no adverse events reported. Randomized control studies are required to confirm the benefits of exercise reported in this study.

Modulating exercise-induced hormesis: Does less equal more?

Hormesis enco 16 mpasses the notion that low levels of stress stimulate or upregulate 17 existing cellular and molecular pathways that improve the capacity of cells and organisms to 18 withstand greater stress. This notion underlies much of what we know about how exercise 19 conditions the body and induces long-term adaptations. During exercise, the body is 20 exposed to various forms of stress, including thermal, metabolic, hypoxic, oxidative, and 21 mechanical stress. These stressors activate biochemical messengers, which in turn activate 22 various signaling pathways that regulate gene expression and adaptive responses. 23 Historically, antioxidant supplements, nonsteroidal anti-inflammatory drugs, and 24 cryotherapy have been favored to attenuate or counteract exercise-induced oxidative stress 25 and inflammation. However, reactive oxygen species and inflammatory mediators are key 26 signaling molecules in muscle, and such strategies may mitigate adaptations to exercise. 27 Conversely, withholding dietary carbohydrate and restricting muscle blood flow during 28 exercise may augment adaptations to exercise. In this review article, we combine, integrate, 29 and apply knowledge about the fundamental mechanisms of exercise adaptation. We also 30 critically evaluate the rationale for using interventions that target these mechanisms under 31 the overarching concept of hormesis. There is currently insufficient evidence to establish 32 whether these treatments exert dose-dependent effects on muscle adaptation. However, 33 there appears to be some dissociation between the biochemical/molecular effects and 34 functional/performance outcomes of some of these treatments. Although several of these 35 treatments influence common kinases, transcription factors and proteins, it remains to be 36 determined if these interventions complement or negate each other, and whether such 37 effects are strong enough to influence adaptations to exercise.

Biomarkers of exercise-induced myocardial stress in relation to inflammatory and oxidative stress

Increased concentrations of biomarkers reflecting myocardial stress such as cardiac troponin I and T and brain natriuretic peptide (BNP) have been observed following strenuous, long-lasting endurance exercise. The pathophysiological mechanisms are still not fully elucidated and the interpretations of increased post-exercise concentrations range from (i) evidence for exercise-induced myocardial damage to (ii) non-relevant spurious troponin elevations, presumably caused by assay imprecision or heterophilic antibodies. Several lines of evidence suggest that inflammatory processes or oxidative stress could be involved in the rise of NT-proBNP and Troponin observed in critically ill patients with sepsis or burn injury. We tested the hypothesis that inflammatory or oxidative stress is also responsible for exercise-induced cardiomyocyte strain in a large cohort of triathletes following an Ironman triathlon. However, the post-race increase in cardiac troponin T and NT-proBNP was not associated with several markers of exercise-induced inflammation, oxidative stress or antioxidant vitamins. Therefore, we clearly need more studies with other inflammatory markers and different designs to elucidate the scientific background for increases in myocardial stress markers following strenuous endurance events.

Exercise-induced DNA damage: Is there a relationship with inflammatory responses?

Both a systemic inflammatory response as well as DNA damage has been observed following exhaustive endurance exercise. Hypothetically, exercise-induced DNA damage might either be a consequence of inflammatory processes or causally involved in inflammation and immunological alterations after strenuous prolonged exercise (e.g. by inducing lymphocyte apoptosis and lymphocytopenia). Nevertheless, up to now only few studies have addressed this issue and there is hardly any evidence regarding a direct relationship between DNA or chromosomal damage and inflammatory responses in the context of exercise. The most conclusive picture that emerges from available data is that reactive oxygen and nitrogen species (RONS) appear to be the key effectors which link inflammation with DNA damage. Considering the time-courses of inflammatory and oxidative stress responses on the one hand and DNA effects on the other the lack of correlations between these responses might also be explained by too short observation periods. This review summarizes and discusses the recent findings on this topic. Furthermore, data from our own study are presented that aimed to verify potential associations between several endpoints of genome stability and inflammatory, immune-endocrine and muscle damage parameters in competitors of an Ironman triathlon until 19 days into recovery. The current results indicate that DNA effects in lymphocytes are not responsible for exercise-induced inflammatory responses. Furthermore, this investigation shows that inflammatory processes, vice versa, do not promote DNA damage, neither directly nor via an increased formation of RONS derived from inflammatory cells. Oxidative DNA damage might have been counteracted by training- and exercise-induced antioxidant responses. However, further studies are needed that combine advanced -omics based techniques (transcriptomics, proteomics) with state-of-the-art biochemical biomarkers to gain more insights into the underlying mechanisms.