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Short-Term Exercise Training Inconsistently Influences Basal Testosterone in Older Men: A Systematic Review and Meta-Analysis.
Hayes, LD, Elliott, BT
Frontiers in physiology. 2018;9:1878
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The levels of testosterone decrease as men age and is associated with accelerated ageing. Approaches to increase testosterone levels may therefore be of benefit. There are complications with administering testosterone and so exercise has been proposed as a non-pharmacological intervention to increase serum testosterone in older males. The purpose of this review and meta-analysis was to look at suitable studies linking exercise and testosterone levels in older males and to see whether types of exercise (endurance, resistance and interval training) made a difference. There is a belief that resistance exercise increases basal testosterone over time. However, this was not observed in this meta-analysis. HIIT (high intensity interval training), and endurance training showed the most promise for increasing basal testosterone in older men. There is a need for more studies to improve the quality of available evidence and at present, exercise is probably the best non-pharmacological countermeasure to loss of muscle function with human aging.
Abstract
Background: The age-associated decrease in testosterone is one mechanism suggested to accelerate the aging process in males. Therefore, approaches to increase endogenous testosterone may be of benefit. The aim of this paper was to undertake a Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)-accordant meta-analysis concerning the effect of exercise on total (TT), bioavailable (bio-T), free (free-T), and salivary (sal-T) testosterone in older males. Methods: Databases were searched up to and including 20th February 2018 for the terms "testosterone AND exercise AND aging AND males," "testosterone AND exercise AND old AND males," "testosterone AND training AND aging AND males," and "testosterone AND training AND old AND males". From 1259 originally identified titles, 22 studies (randomized controlled trials; RCTs; n = 9, and uncontrolled trials; UCTs; n = 13) were included which had a training component, participants ≥60 years of age, and salivary or serum testosterone as an outcome measure. Meta-analyses were conducted on change to testosterone following training using standardized difference in means (SDM) and random effects models. Results: The overall SDM for endurance training, resistance training, and interval training was 0.398 (95% CI = 0.034-0.761; P = 0.010), -0.003 (95% CI = -0.330-0.324; P = 0.986), and 0.283 (95% CI = 0.030-0.535; P = 0.028), respectively. Resistance training exhibited a qualitative effect of hormone fraction whereby free-T resulted in the greatest SDM (0.253; 95% CI = -0.043-0.549; P = 0.094), followed by TT (0.028; 95% CI = -0.204-0.260; P = 0.813), and resistance training negatively influenced bio-T (-0.373; 95% CI = -0.789-0.042; P = 0.078). Due to the small number of studies, subgroup analysis was not possible for endurance training and interval training studies. Conclusions: Data from the present investigation suggests that resistance training does not significantly influence basal testosterone in older men. Magnitude of effect was influenced by hormone fraction, even within the same investigation. Aerobic training and interval training did result in small, significant increases in basal testosterone. The magnitude of effect is small but the existing data are encouraging and may be an avenue for further research.
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The impact of sleeping with reduced glycogen stores on immunity and sleep in triathletes.
Louis, J, Marquet, LA, Tiollier, E, Bermon, S, Hausswirth, C, Brisswalter, J
European journal of applied physiology. 2016;116(10):1941-54
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Endurance athletes are increasingly using training strategies focused on low glycogen availability in attempt to improve performance. It is well known, however, that increasing training stress could influence immune function and increase the risk of illness or injury. In endurance sports, training load, nutrient intake and sleep are key factors in modulating immune function. The aim of this study was to investigate the effects of a 3-week training strategy involving lowered glycogen availability overnight on immune function, upper respiratory tract infections and sleep patterns in 21 trained endurance athletes. This study found that reduced glycogen availability resulted in significantly faster 10km running times, and found no significant changes in the recorded immunity markers. Based on this study, the authors conclude that reduced glycogen availability has no deleterious impact on immune function.
Abstract
PURPOSE We investigated the effects of a 3-week dietary periodization on immunity and sleep in triathletes. METHODS 21 triathletes were divided into two groups with different nutritional guidelines during a 3-week endurance training program including nine twice a day sessions with lowered (SL group) or maintained (CON group) glycogen availability during the overnight recovery period. In addition to performance tests, sleep was monitored every night. Systemic and mucosal immune parameters as well as the incidence of URTI were monitored every week of the training/nutrition protocol. Two-ways ANOVA and effect sizes were used to examine differences in dependent variables between groups at each time point. RESULTS The SL group significantly improved 10 km running performance (-1 min 13 s, P < 0.01, d = 0.38), whereas no improvement was recorded in the CON group (-2 s, NS). No significant changes in white blood cells counts, plasma cortisol and IL-6 were recorded over the protocol in both groups. The vitamin D status decreased in similar proportions between groups, whereas salivary IgA decreased in the SL group only (P < 0.05, d = 0.23). The incidence of URTI was not altered in both groups. All participants in both groups went to bed earlier during the training program (SL -20 min, CON -27 min, P < 0.05, d = 0.28). In the SL group, only sleep efficiency slightly decreased by 1.1 % (P < 0.05, d = 0.25) and the fragmentation index tended to increase at the end of the protocol (P = 0.06). CONCLUSION Sleeping and training the next morning regularly with reduced glycogen availability has minimal effects on selected markers of immunity, the incidence of URTI and sleeping patterns in trained athletes.
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Feasibility outcomes of a presurgical randomized controlled trial exploring the impact of caloric restriction and increased physical activity versus a wait-list control on tumor characteristics and circulating biomarkers in men electing prostatectomy for prostate cancer.
Demark-Wahnefried, W, Nix, JW, Hunter, GR, Rais-Bahrami, S, Desmond, RA, Chacko, B, Morrow, CD, Azrad, M, Frugé, AD, Tsuruta, Y, et al
BMC cancer. 2016;16:61
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There is a strong body of evidence associating obesity and increased risk for more aggressive and progressive cancer. This paper aims to assess the feasibility of a presurgical diet and exercise weight loss intervention in men with newly-diagnosed prostate cancer who elected for prostatectomy. It also aims to explore the intervention’s effects on tumour proliferation rates and other biomarkers. The 3-weeks randomised controlled study included 40 overweight or obese men newly-diagnosed with prostate cancer. Participants in experimental arm were assigned to a healthy energy-restricted diet versus wait-list control arm. All feasibility endpoints were achieved with accrual completed within 2 years, retention of 85%, adherence of 95% and no adverse events. Biologic outcomes were not included in this paper, as biological testing was still ongoing. Authors concluded that this study’s methods and data on feasibility could provide useful framework for the design of future trials. They also highlighted the importance of presurgical trials as a feasible and safe means to assess the impacts of diet and exercise on tumour tissue.
Abstract
BACKGROUND Obesity is associated with tumor aggressiveness and disease-specific mortality for more than 15 defined malignancies, including prostate cancer. Preclinical studies suggest that weight loss from caloric restriction and increased physical activity may suppress hormonal, energy-sensing, and inflammatory factors that drive neoplastic progression; however, exact mechanisms are yet to be determined, and experiments in humans are limited. METHODS We conducted a randomized controlled trial among 40 overweight or obese, newly-diagnosed prostate cancer patients who elected prostatectomy to explore feasibility of a presurgical weight loss intervention that promoted a weight loss of roughly one kg. week(-1) via caloric restriction and physical activity, as well as to assess effects on tumor biology and circulating biomarkers. Measures of feasibility (accrual, retention, adherence, and safety) were primary endpoints. Exploratory aims were directed at the intervention's effect on tumor proliferation (Ki-67) and other tumor markers (activated caspase-3, insulin and androgen receptors, VEGF, TNFβ, NFκB, and 4E-BP1), circulating biomarkers (PSA, insulin, glucose, VEGF, TNFβ, leptin, SHBG, and testosterone), lymphocytic gene expression of corresponding factors and cellular bioenergetics in neutrophils, and effects on the gut microbiome. Consenting patients were randomized in a 1:1 ratio to either: 1) weight loss via a healthful, guidelines-based diet and exercise regimen; or 2) a wait-list control. While biological testing is currently ongoing, this paper details our methods and feasibility outcomes. RESULTS The accrual target was met after screening 101 cases (enrollment rate: 39.6%). Other outcomes included a retention rate of 85%, excellent adherence (95%), and no serious reported adverse events. No significant differences by age, race, or weight status were noted between enrollees vs. non-enrollees. The most common reasons for non-participation were "too busy" (30%), medical exclusions (21%), and "distance" (16%). CONCLUSIONS Presurgical trials offer a means to study the impact of diet and exercise interventions directly on tumor tissue, and other host factors that are feasible and safe, though modifications are needed to conduct trials within an abbreviated period of time and via distance medicine-based approaches. Pre-surgical trials are critical to elucidate the impact of lifestyle interventions on specific mechanisms that mediate carcinogenesis and which can be used subsequently as therapeutic targets. TRIAL REGISTRATION NCT01886677.
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Influence of a montmorency cherry juice blend on indices of exercise-induced stress and upper respiratory tract symptoms following marathon running--a pilot investigation.
Dimitriou, L, Hill, JA, Jehnali, A, Dunbar, J, Brouner, J, McHugh, MP, Howatson, G
Journal of the International Society of Sports Nutrition. 2015;12:22
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Prolonged exercise, such as marathon running, is associated with upper respiratory tract (URT) symptoms and airway inflammation. Tart Montmorency cherry juice, high in phytochemicals such as anthocyanins and quercetin, has been shown to have anti-inflammatory and anti-oxidative properties and therefore may help reduce inflammation and oxidative stress triggered by exercise. In this pilot study, twenty marathon runners were randomly assigned to receive two servings a day of either a placebo drink or cherry juice for eight days ─ prior, during and after a marathon run. Any URT symptoms were reported, and inflammatory markers were measured pre- and post-race and 24 and 48 hrs after the race, from saliva (immunoglobulins and cortisol) and serum (C-reactive protein, CRP). No differences in the effect on immunoglobulins and cortisol were found between the two groups. The increase in CRP was significantly lower in the cherry juice group compared to the placebo group. 50% of the runners in the placebo group developed URT symptoms, while none were reported in the cherry juice group. The authors conclude that Montmorency cherry juice may protect the URT from inflammatory symptoms triggered by exercise. They propose further studies with larger sample size of participants, suffering from various inflammatory respiratory conditions.
Abstract
BACKGROUND Prolonged exercise, such as marathon running, has been associated with an increase in respiratory mucosal inflammation. The aim of this pilot study was to examine the effects of Montmorency cherry juice on markers of stress, immunity and inflammation following a Marathon. METHODS Twenty recreational Marathon runners consumed either cherry juice (CJ) or placebo (PL) before and after a Marathon race. Markers of mucosal immunity secretory immunoglobulin A (sIgA), immunoglobulin G (IgG), salivary cortisol, inflammation (CRP) and self-reported incidence and severity of upper respiratory tract symptoms (URTS) were measured before and following the race. RESULTS All variables except secretory IgA and IgG concentrations in saliva showed a significant time effect (P <0.01). Serum CRP showed a significant interaction and treatment effect (P < 0.01). The CRP increase at 24 and 48 h post-Marathon was lower (P < 0.01) in the CJ group compared to PL group. Mucosal immunity and salivary cortisol showed no interaction effect or treatment effect. The incidence and severity of URTS was significantly greater than baseline at 24 h and 48 h following the race in the PL group and was also greater than the CJ group (P < 0.05). No URTS were reported in the CJ group whereas 50 % of runners in the PL group reported URTS at 24 h and 48 h post-Marathon. CONCLUSIONS This is the first study that provides encouraging evidence of the potential role of Montmorency cherries in reducing the development of URTS post-Marathon possibly caused by exercise-induced hyperventilation trauma, and/or other infectious and non-infectious factors.