Exercise improves depression through positive modulation of brain-derived neurotrophic factor (BDNF). A review based on 100 manuscripts over 20 years.

The aim of this review was to explore the relevant neurobiology and the association between peripheral levels of brain-derived neurotrophic factor (BDNF) and acute and short to long-term exercise regimes, as well as its relation to depression and antidepressant treatment. A 20-year literature search was conducted. The screening process resulted in 100 manuscripts. Antidepressants as well as acute exercise, particularly high-intensity, elevates BDNF in healthy humans and clinical populations, as evidenced from aerobic and resistance-based studies. Although exercise is increasingly recognised in the management of depression, acute and short-term exercise studies have failed to establish a relationship between the severity of depression and changes in peripheral BDNF. The latter rapidly returns to baseline, possibly indicating a quick re-uptake by the brain, aiding its neuroplasticity functions. The timescale of administration needed for the antidepressants to stimulate biochemical changes is longer than similar increases with acute exercise.

Investigating the Relationship between Big Five Personality Traits and Sports Performance among Disabled Athletes.

Awareness of the psychological issues of different groups of society can help in the management of sports programs and thus improve their athletic performance. The aim of the present study was to investigate the relationship between the big five personality traits and the sports performance of disabled athletes in team sports. Three hundred and seventy-six team athletes participated in the study. Subjects completed a questionnaire of five major personality factors, and based on the information available on the provincial boards and the Veterans and Disabled Federation, the positions obtained by each athlete were considered as a criterion for sports performance. There was a significant relationship between the flexibility factor for men and women (r = 0.123, p = 0.017), neuroticism (r = 0.114, p = 0.027), adaptation (r = 0.171, p = 0.001), extraversion (r = 0.157, p = 0.002), duty orientation (r = 0.104, p = 0.045), and sports performance at a national level. There was a significant relationship between neuroticism (r = 0.142, p = 0.006), adaptation (r = 0.133, p = 0.010), extraversion (r = 0.163, p = 0.002), and duty orientation (r = 0.130, p = 0.011) with sports performance at a provincial level. There was a significant relationship between neuroticism (r = 0.156, p = 0.002), extraversion (r = 0.168, p = 0.001), duty orientation (r = 0.182, p = 0.001), and sports performance at international level. Disabled athletes seem to have above-average performance scores in most personality factors, which can improve their physical health and increase their success in sports.

Evaluation of health-related quality of life in physically active and physically inactive students during the COVID-19 pandemic in Iran.

Covid-19 is an acute respiratory syndrome that can effect on lifestyles. The aim of the present study was to compare the health-related quality of life (HRQoL), physical component summary (PCS) and mental component summary (MCS) scores in physically active (PA) and physically inactive (PI) during the Covid-19 pandemic. Three hundred and twenty-six (182 women; 144 men) studying at the Persian Gulf University participated in the study. The HRQoL Questionnaire (SF-12) was used to collect information. Significant differences in HRQoL score, MCS score and PCS score were observed between physically active and inactive men and women, as well as between physically active and inactive men, and finally between physically active and inactive women (P < 0.01). Data from the present study suggests higher levels of physical activity, even during social restrictions imposed by the current global pandemic, results in significantly greater scores for HRQoL.

Developing a New Curvilinear Allometric Model to Improve the Fit and Validity of the 20-m Shuttle Run Test as a Predictor of Cardiorespiratory Fitness in Adults and Youth.

BACKGROUND AND OBJECTIVES: Doubts have been raised concerning the validity of the 20-m shuttle-run test (20 mSRT) as a predictor of cardiorespiratory fitness (CRF) in youth based on Léger's equation/model. An alternative allometric model has been published recently that is thought to provide, not only a superior fit (criterion validity) but also a more biologically and physiologically interpretable model (construct validity). The purposes of this study were to explore whether allometry can provide a more valid predictor of CRF using 20 mSRT compared with Léger's equation/model. METHODS: We fitted and compared Léger's original model and an alternative allometric model using two cross-sectional datasets (youth, n = 306; adult n = 105) that contained measurements of CRF ([Formula: see text]/[Formula: see text]) and 20 mSRT performance. Quality-of-fit was assessed using explained variance (R2) and Bland and Altman's limits of agreement. RESULTS: The allometric models provided superior fits for the youth (explained variance R2 = 71.9%) and adult (R2 = 77.7%) datasets compared with Léger's equation using their original fixed (R2 = 35.2%) or re-estimated parameter models (R2 = 65.9%), confirming that the allometric models demonstrate acceptable criterion validity. However, the allometric models also identified a non-linear "J-shaped" increase in energy cost ([Formula: see text]/[Formula: see text]) with faster final shuttle-run speeds (fitted speed exponent = 1.52; 95% CI 1.38-1.65). CONCLUSION: Not only do allometric models provide more accurate predictions of CRF ([Formula: see text]/[Formula: see text]; ml kg-1 min-1) for both youth and adults (evidence of criterion validity), the "J-shaped" rise in energy demand with increasing final shuttle-run speed also provides the evidence of construct validity, resulting in a more plausible, physiologically sound, and interpretable model.

Effects of Physical Activity on Brain Energy Biomarkers in Alzheimer's Diseases.

The prevalence of dementia has substantially increased worldwide. Currently, there is no cure for dementia or Alzheimer's disease (AD), and care for affected patients is financially and psychologically costly. Of late, more attention has been given to preventive interventions-in particular, physical activity/exercise. In this review, examine the risk factors associated with AD and the effects physical activity may play in the prevention of the degenerative process of this disease, loss of memory and cognitive performance in the elderly. To date, research has shown that physical activity, especially aerobic exercise, has a protective effect on cognitive function and memory in the elderly and Alzheimer's patients. In comparison with aerobic exercise, several strength training studies have also shown positive effects, and the rare studies that compare the two different modalities show no difference.

Angiotensin involvement in trauma processing-exploring candidate neurocognitive mechanisms of preventing post-traumatic stress symptoms.

The angiotensin-II antagonist losartan is a promising candidate that has enhanced extinction in a post-traumatic stress disorder (PTSD) animal model and was related to reducing PTSD symptom development in humans. Here, we investigate the neurocognitive mechanisms underlying these results, testing the effect of losartan on data-driven and contextual processing of traumatic material, mechanisms proposed to be relevant for PTSD development. In a double-blind between-subject design, 40 healthy participants were randomised to a single oral dose of losartan (50 mg) or placebo, 1 h before being exposed to distressing films as a trauma analogue while heart rate (HR) was measured. Peritraumatic processing was investigated using blurry picture stimuli from the films, which transformed into clear images. Data-driven processing was measured by the level of blurriness at which contents were recognised. Contextual processing was measured as the amount of context information retrieved when describing the pictures' contents. Negative-matched control images were used to test perceptual processing of peripheral trauma-cues. Post-traumatic stress symptoms were assessed via self-report questionnaires after analogue trauma and an intrusion diary completed over 4 days following the experiment. Compared to placebo, losartan facilitated contextual processing and enhanced detail perception in the negative-match pictures. During the films, the losartan group recorded lower HR and higher HR variability, reflecting lower autonomic stress responses. We discuss potential mechanisms of losartan in preventing PTSD symptomatology, including the role of reduced arousal and increased contextual processing during trauma exposure, as well as increased threat-safety differentiation when encountering peripheral trauma-cues in the aftermaths of traumatic events.

Effects of Three-Day Serial Sodium Bicarbonate Loading on Performance and Physiological Parameters During a Simulated Basketball Test in Female University Players.

The aim of this study was to investigate the effect of 3-day serial sodium bicarbonate ingestion on repeated sprint and jump performance. Fifteen female university basketball players (23.3 ± 3.4 years; 173.1 ± 5.8 cm; 65.8 ± 6.3 kg; 23.6 ± 4.9% body fat) ingested 0.4 g/kg body mass of sodium bicarbonate or placebo for 3 days (split in three equal daily doses), before completing a simulated basketball exercise. Sprint and circuit times, jump heights, performance decrements, and gastrointestinal side effects were recorded during the test, and blood lactate concentration was measured pre- and posttest. Sodium bicarbonate supplementation led to significant decreases in mean sprint times (1.34 ± 0.23 vs. 1.70 ± 0.41 s, p = .008, 95% confidence intervals [-0.54, -0.10 s]) and mean circuit times (30.6 ± 2.0 vs. 31.3 ± 2.0 s, p = .044) and significantly greater mean jump height (26.8 [range 25.2-34.2] vs. 26.0 [range 25.6-33.6] cm, p = .013) compared with placebo. Performance decrement was significantly less for sprints with sodium bicarbonate compared with placebo (9.9 [range 3.4-37.0]% vs. 24.7 [range 4.1-61.3]%, p = .013), but not different for jumps (13.1 ± 4.5% vs. 12.5 ± 3.1%, p = .321) between conditions. No differences in gastrointestinal side effects were noted between conditions. Significantly greater postexercise blood lactate concentrations were measured in the sodium bicarbonate condition compared with the placebo condition (8.2 ± 2.8 vs. 6.6 ± 2.4 mmol/L, p = .010). This study is the first to show that serial loading of sodium bicarbonate is effective for basketball players to improve repeated sprint and jump performance during competition, or withstand greater training load during practice sessions without any gastrointestinal side effects.

No Dose-Response Effect of Carbohydrate Mouth Rinse Concentration on 5-km Running Performance in Recreational Athletes.

Clarke, ND, Thomas, JR, Kagka, M, Ramsbottom, R, and Delextrat, A. No dose-response effect of carbohydrate mouth rinse concentration on 5-km running performance in recreational athletes. J Strength Cond Res 31(3): 715-720, 2017-Oral carbohydrate rinsing has been demonstrated to provide beneficial effects on exercise performance of durations of up to 1 hour, albeit predominately in a laboratory setting. The aim of the present study was to investigate the effects of different concentrations of carbohydrate solution mouth rinse on 5-km running performance. Fifteen healthy men (n = 9; mean ± SD age; 42 ± 10 years; height, 177.6 ± 6.1 cm; body mass, 73.9 ± 8.9 kg) and women (n = 6; mean ± SD age, 43 ± 9 years; height, 166.5 ± 4.1 cm; body mass, 65.7 ± 6.8 kg) performed a 5-km running time trial on a track on 4 separate occasions. Immediately before starting the time trial and then after each 1 km, subjects rinsed 25 ml of 0, 3, 6, or 12% maltodextrin for 10 seconds. Mouth rinsing with 0, 3, 6, or 12% maltodextrin did not have a significant effect on the time to complete the time trial (0%, 26:34 ± 4:07 minutes:seconds; 3%, 27:17 ± 4:33 minutes:seconds; 6%, 27:05 ± 3:52 minutes:seconds; 12%, 26:47 ± 4.31 minutes:seconds; p = 0.071; (Equation is included in full-text article.)= 0.15), heart rate (p = 0.095; (Equation is included in full-text article.)= 0.16), rating of perceived exertion (p = 0.195; (Equation is included in full-text article.)= 0.11), blood glucose (p = 0.920; (Equation is included in full-text article.)= 0.01), and blood lactate concentration (p = 0.831; (Equation is included in full-text article.)= 0.02), with only nonsignificant trivial to small differences between concentrations. Results of this study suggest that carbohydrate mouth rinsing provides no ergogenic advantage over an acaloric placebo (0%) and that there is no dose-response relationship between carbohydrate solution concentration and 5-km track running performance.

Cardio-respiratory fitness, habitual physical activity and serum brain derived neurotrophic factor (BDNF) in men and women.

Short episodes of high intensity exercise transiently increase serum levels of BDNF in humans, but serum levels of BDNF at rest appear to be lower in more physically active humans with greater levels of energy expenditure. The relationship between serum BDNF concentration, cardio-respiratory fitness (Astrand-Rhyming test estimated VO2 max) and volume of long-term, regular exercise and sporting activity (Baecke Habitual Physical Activity Index) was investigated in 44 men and women between the age range of 18-57 years. In this group an inverse relationship between resting serum BDNF concentration and measures of both estimated VO2 max (r=-0.352; P<0.05) and long-term sporting activity (r=-0.428, P<0.01) was found. These results indicate that increased levels of cardio-respiratory fitness and habitual exercise are associated with lower resting levels of serum BDNF in healthy humans. This is the first study to demonstrate an inverse relationship between a physiological estimate of cardio-respiratory fitness and serum BDNF.

Change in heart rate variability following orthostasis relates to volume of exercise in healthy women.

Physically active individuals demonstrate increased heart rate variability (HRV) during rest compared to sedentary individuals, but the impact of different volumes of regular exercise on the HRV response to postural change is not well understood. This study investigates change in HRV following orthostasis in seventy-two young women who exercise at low (LV) or high (HV) volumes of physical activity. Supine and standing R-R intervals were analysed by time domain, frequency domain and Poincaré plot methods. All methods revealed greater change in the vagal response in the HV group, indicating that HRV following postural change is modulated by volume of exercise.

Measures of cardiac autonomic control in women with differing volumes of physical activity.

In this study, we investigated heart rate variability in women who exercise regularly, but with differing volumes of physical activity. Forty women participated and were allocated to either a "high" or "moderate" activity group. Heart rate as R-R intervals was recorded during supine rest and analysed using time domain, frequency domain, and Poincaré plot techniques. All time domain and Poincaré analysis measures revealed significant differences in heart rate variability between the "high" and "moderate" activity groups. Frequency domain analysis also revealed a significant difference between the two groups in absolute measures of high-frequency and low-frequency power, but not between measures such as the low-frequency/high-frequency ratio, proposed to represent the sympathetic/parasympathetic balance of cardiac control. The results demonstrate that there is a significant difference in heart rate variability between women who engage in "high" compared with "moderate" volumes of physical activity, which may have implications for cardiac autonomic health.

Oxygen cost during treadmill walking with hip and knee immobilised.

The aim of this study was to determine the effect of immobilising the knee and hip on the oxygen cost (ml·kg(-1)·min(-1)) to velocity relationship during treadmill walking. The study was a prospective experimental conducted in a Rehabilitation centre. Ten healthy individuals, five men and five women, with no gait abnormality participated. Following familiarisation five men and five women walked on a treadmill and selected their own, free "comfortable walking velocity "(SSWS). Subjects then performed an incremental test at -60 to +60% of SSWS. Individuals later repeated the test with the knee and hip of one limb immobilised. Samples of expired air were measured at each velocity and the oxygen cost (ml·kg(-1)·min(-1)) to Froude number (Fr) relationship plotted (where calculation of Fr normalizes for subjects of differing leg length and acts as an index of velocity). There was a higher oxygen cost, and lower Fr at SSWS during immobilised (0.21 ± 0.03 ml·kg(-1)·min(-1); Fr = 0.12 ± 0. 03) compared with free walking (0.16 ± 0.02 ml·kg(-1)·min(-1); Fr = 0.18 ± 0.04) (p < 0. 01). Statistical analysis demonstrated that during immobilised walking an inverse fit (y = ß0 + ß1/x) and for free walking a cubic fit (y = ß0 + ß1x + ß2x(2) + ß3x(3) ) best fitted the data. Hip and knee immobilisation increased the oxygen cost at SSWS and altered the oxygen cost to Fr relationship. The results have implications in selecting optimal walking velocities in individuals with impairments affecting mobility such as hemiplegic gait. Key PointsWalking with one limb immobilised requires greater energy cost than normal free walking.This has clinical implications when developing rehabilitation strategies for patients who mobility problems such as those with hemi paretic gait.

A pilot study to investigate explosive leg extensor power and walking performance after stroke.

We examined explosive leg extensor power (LEP) and gait in men and women after a stroke using an experimental observational design. A convenience sample of consecutively referred individuals (8 men, 6 women) with chronic stroke mean age ± SD, range, 46.4 ± 8.4, 32 - 57 years, and able to walk for four minutes were recruited. The test re-test reliability and performance of LEP was measured together with walking parameters. LEP (Watts·kg(-1)) and gait measures during a four-minute walk; temporal-spatial gait parameters (GAITRite(®)) and oxygen cost of walking (mL·kg(-1)·m(-1)) were recorded. Percentage Asymmetry LEP (stronger LEP - weaker LEP/stronger LEP x 100) was calculated for each person. LEP was reliable from test to re-test ICC [3, 1] 0.8 - 0.7 (n = 9). Greater Asymmetry LEP correlated strongly with reduced walking velocity, cadence, stance time, and swing time on the weaker leg (n = 14) (p < 0.01). Findings demonstrate explosive LEP, in particular Percentage Asymmetry LEP, can be measured after stroke and is both reliable and related to walking performance. LEP training of the stronger or weaker leg warrants further investigation in this group. Key PointsExplosive leg power (LEP) is a reliable measure in individuals recovering from a stroke.Significant asymmetry occurred in LEP in this group.Greater LEP asymmetry related to reduced walking performance after stroke.

Measuring oxygen cost during level walking in individuals with acquired brain injury in the clinical setting.

This study examined the test-retest reliability of oxygen cost (ml·kg(-1)·min(-1)) during level walking in individuals with acquired brain injury (ABI). Ten individuals with ABI (5 men, 5 women) (Traumatic brain injury, 1, central pontine myelinolysis, 1, stroke 8) and 21 healthy controls (11 men, 10 women). Measurements of gross and net (walking minus resting) oxygen consumption (ml·kg(-1)·min(-1)), and oxygen cost (ml·kg(-1)·min(-1)) during level walking at self-selected speeds. Measurements were taken on two occasions within one week. Oxygen cost was significantly lower (p < 0.05) in individuals with ABI on the second test versus the first test. Percentage variability in oxygen cost from test to re-test ranged from 14.7 to 17.3% in the control group and from 17.4 to 20.8% in the brain injury group. Clinical populations may demonstrate a significant decrease in oxygen cost between testing occasions. Individuals require at least one period of familiarisation if oxygen cost is used as an outcome measure during level walking in clinical groups. The amount of familiarisation has yet to be investigated in individuals with ABI. Key PointsIndividuals with brain injury during level walkingMay demonstrate a significant decrease in oxygen cost between testing occasions.May require at least one period of familiarisation if oxygen cost is used as an outcome measureThe degree of familiarisation required in this clinical group needs further investigation.

The effect of 6 months training on leg power, balance, and functional mobility of independently living adults over 70 years old.

Where strength training has been used in conjunction with functional-task training in older people, not only have there been improvements in leg strength but also improved function has been measured (e.g., Skelton & McLaughlin, 1996). Many studies use participants from care homes rather than community dwellers. We investigated changes in leg power, balance, and functional mobility in community-dwelling sedentary men and women over 70 years of age (n = 6 for training group [TR]; n = 10 for control group [CN]). Progressive training took place over 24 weeks using seated and nonseated exercise. For TR, leg power increased 40%, from 108 +/- 40 to 141 +/- 53 W (p < .01); dynamic balance increased 48%, from 22.3 +/- 7.9 to 33.1 +/- 6.1 cm (p < .01; functional reach); and functional mobility increased 12%, from 7.46 +/- 1.32 to 6.54 +/- 1.41 s (p < .05; timed walk). CN showed no significant change. In conclusion, a community-based exercise program led to large improvements in leg-extensor power, dynamic balance, and functional mobility.