Converging evidence from animal models of stroke and clinical trials suggests that aerobic exercise has effects across multiple targets.
The subacute phase is characterized by a period of heightened ...neuroplasticity when aerobic exercise has the potential to optimize recovery. In animals, low intensity aerobic exercise shrinks lesion size and reduces cell death and inflammation, beginning 24 h poststroke. Also in animals, aerobic exercise upregulates brain-derived neurotrophic factor near the lesion and improves learning. In terms of neuroplastic effects, clinical trial results are less convincing and have only examined effects in chronic stroke. Stroke patients demonstrate cardiorespiratory fitness levels below the threshold required to carry out daily activities. This may contribute to a 'neurorehabilitation ceiling' that limits capacity to practice at a high enough frequency and intensity to promote recovery. Aerobic exercise when delivered 2-5 days per week at moderate to high intensity beginning as early as 5 days poststroke improves cardiorespiratory fitness, dyslipidemia, and glucose tolerance.
Based on the evidence discussed and applying principles of periodization commonly used to prepare athletes for competition, we have created a model of aerobic training in subacute stroke in which training is delivered in density blocks (duration × intensity) matched to recovery phases.
Self‐talk is an effective mental training technique that has been shown to facilitate or debilitate an athlete's performance, depending on its valence. Although the effects of self‐talk have been ...supported by observing change in sport performance, little is known about how self‐talk can induce physiological changes. Specifically, it is important to understand if the type of self‐talk (positive, neutral, or negative) and can influence stress‐related parameters, such as perceived exertion, cardiorespiratory, and cortisol responses. The study's objective was therefore to investigate the top‐down effect of positive and negative self‐talk compared to a dissociative activity during an iso‐metabolic running exercise on autonomic regulation of cardiorespiratory function. Twenty‐nine well‐trained male runners 38 ± 13 years, 177 ± 7 cm and 73 ± 7 kg volunteered to participate in a randomized‐group design study that included a negative self‐talk (NST), a positive self‐talk, and a dissociative group (DG). First, participants underwent an incremental running test on a treadmill to determine the maximal oxygen uptake (V̇O2max). Next, participants received a mental training session on self‐talk and created three positive and three negative self‐talk statements. Finally, participants underwent a 60‐min steady‐state running exercise on a treadmill at 70% of V̇O2max, during which they were cued at 20‐, 35‐, and 50‐min with their personal self‐created positive or negative self‐talk statements while the DG listened to a documentary. Cardiorespiratory parameters and rate of perceived exertion (RPE) were recorded throughout the 60‐min endurance exercise. In addition, salivary cortisol samples were obtained at waking and after treatment. Although oxygen uptake, carbon dioxide production, RPE, and heart rate significantly changed overtime during the 60‐min steady‐state running exercise, no significant main treatment effect was found. However, RPE scores, minute ventilation, breathing frequency, and salivary cortisol were significantly higher in the NST group compared to the two other groups. These data suggest that NST emotion‐induced stress, as reflected by elevated cortisol altered the breathing frequency response. In conclusion, manipulating self‐talk alters hormonal response patterns, modulates cardiorespiratory function, and influences perceived exertion.
To date, there have been no studies specifically designed to explore the neural functional connections that would specifically elucidate the top‐down neurophysiological pathway associating self‐talk during exercise. This study demonstrates that emotion‐induced stress alters the neural functional connections as reflected in cardiovascular and hormonal responses.
As a demonstration of an alternative to the challenges faced with batch pharmaceutical manufacturing including the large production footprint and lengthy time‐scale, we previously reported a ...refrigerator‐sized continuous flow system for the on‐demand production of essential medicines. Building on this technology, herein we report a second‐generation, reconfigurable and 25 % smaller (by volume) continuous flow pharmaceutical manufacturing platform featuring advances in reaction and purification equipment. Consisting of two compact 0.7 (L)×0.5 (D)×1.3 m (H) stand‐alone units for synthesis and purification/formulation processes, the capabilities of this automated system are demonstrated with the synthesis of nicardipine hydrochloride and the production of concentrated liquid doses of ciprofloxacin hydrochloride, neostigmine methylsulfate and rufinamide that meet US Pharmacopeia standards.
On‐demand pharmaceutical production: The capabilities of a second‐generation, compact, continuous flow platform for on‐demand pharmaceutical manufacturing are demonstrated with the synthesis of nicardipine hydrochloride and the production of concentrated liquid doses of ciprofloxacin hydrochloride, neostigmine methylsulfate and rufinamide that meet US Pharmacopeia standards.
The primary objective of the current study was to determine the effect of moderate normobaric hypoxia exposure during constant load cycling on post-exercise energy metabolism recorded in normoxia. ...Indirect calorimetry was used to examine whole body substrate oxidation before, during, 40-60 min post, and 22 h after performing 60 min of cycling exercise at two different fractions of inspired oxygen (F
O
): (i) F
O
= 0.2091 (normoxia) and (ii) F
O
= 0.15 (hypoxia). Seven active healthy male participants (26 ± 4 years of age) completed both experimental trials in randomized order with a 7-day washout period to avoid carryover effects between conditions. Resting energy expenditure was initially elevated following cycling exercise in normoxia and hypoxia (Δ 0.14 ± 0.05, kcal min
,
= 0.037; Δ 0.19 ± 0.03 kcal min
,
< 0.001, respectively), but returned to baseline levels the next morning in both conditions. Although, the same absolute workload was used in both environmental conditions (157 ± 10 W), a shift in resting substrate oxidation occurred after exercise performed in hypoxia while post-exercise measurements were similar to baseline after cycling exercise in normoxia. The additional metabolic stress of hypoxia exposure was sufficient to increase the rate of lipid oxidation (Δ 42 ± 11 mg min
,
= 0.019) and tended to suppress carbohydrate oxidation (Δ -55 ± 26 mg min
,
= 0.076) 40-60 min post-exercise. This shift in substrate oxidation persisted the next morning, where lipid oxidation remained elevated (Δ 9 ± 3 mg min
,
= 0.0357) and carbohydrate oxidation was suppressed (Δ -22 ± 6 mg min
,
= 0.019). In conclusion, prior exercise performed under moderate normobaric hypoxia alters post-exercise energy metabolism. This is an important consideration when evaluating the metabolic consequences of hypoxia exposure during prolonged exercise, and future studies should evaluate its role in the beneficial effects of intermittent hypoxia training observed in persons with obesity and insulin resistance.
To compare the oxygen costs of mobility tasks between individuals with progressive multiple sclerosis (MS) using walking aids and matched controls and to determine whether oxygen cost predicted ...fatigue.
Cross-sectional descriptive.
A rehabilitation research laboratory.
A total of 14 adults with progressive MS (mean age ± SD y, 54.07±8.46) using walking aids and 8 age- and sex-matched controls without MS (N=22).
Participants performed 5 mobility tasks (rolling in bed, lying to sitting, sitting to standing, walking, climbing steps) wearing a portable metabolic cart.
Oxygen consumption (V˙o
) during mobility tasks, maximal V˙o
during graded maximal exercise test, perceived exertion, and task-induced fatigue were measured on a visual analog scale before and after mobility tasks.
People with progressive MS had significantly higher oxygen cost in all tasks compared to controls (P<.05): climbing steps (3.60 times more in MS), rolling in bed (3.53), walking (3.10), lying to sitting (2.50), and sitting to standing (1.82). There was a strong, positive correlation between task-induced fatigue and oxygen cost of walking, (ρ 13=0.626, P=.022).
People with progressive MS used 2.81 times more energy on average for mobility tasks compared to controls. People with progressive MS experienced accumulation of oxygen cost, fatigue, and exertion when repeating tasks and higher oxygen cost during walking was related to greater perception of fatigue. Our findings suggest that rehabilitation interventions that increase endurance during functional tasks could help reduce fatigue in people with progressive MS who use walking aids.
To evaluate the safety and feasibility of performing treadmill aerobic exercise in moderate normobaric hypoxia among chronic hemiparetic stroke survivors.
Observational study using convenience ...sampling.
Research laboratory in a tertiary rehabilitation hospital.
Chronic hemiparetic stroke survivors who could walk at least 10-m with or without assistance and had no absolute contraindications to exercise testing.
Participants (three male and four female) were asked to complete three normobaric hypoxia exposure protocols within a single session. First, they were passively exposed to normobaric hypoxia through gradual reductions in the fraction of inspired oxygen (F
O
= 20.9, 17.0, and 15.0%) while seated (5-min at each level of F
O
). Participants were then exposed to the same reductions in F
O
during constant-load exercise performed on a treadmill at 40% of heart rate reserve. Finally, participants completed 20-min of exercise while intermittently exposed to moderate normobaric hypoxia (5 × 2-min at F
O
= 15.0%) interspaced with 2-min normoxia intervals (F
O
= 20.9%).
The primary outcome was occurrence of adverse events, which included standardized criteria for terminating exercise testing, blood oxygen saturation (S
O
) <80%, or acute mountain sickness score >2. The increased cardiovascular strain imposed by normobaric hypoxia exposure at rest and during exercise was evaluated by changes in S
O
, heart rate (HR), blood pressure, and rating of perceived exertion (RPE).
One participant reported mild symptoms of nausea during exercise in normobaric hypoxia and discontinued participation. No other adverse events were recorded. Intermittent normobaric hypoxia exposure was associated with reduced S
O
(MD = -7.4%, CI: -9.8 to -5.0) and increased HR (MD = 8.2, CI: 4.6 to 11.7) compared to intervals while breathing typical room air throughout the 20-min constant-load exercise period. The increase in HR was associated with a 10% increase in relative effort. However, reducing F
O
had little effect on blood pressure and RPE measurements.
Moderate normobaric hypoxia appeared to be a safe and feasible method to increase the cardiovascular strain of submaximal exercise in chronic hemiparetic stroke survivors. Future studies evaluating the effects of pairing normobaric hypoxia exposure with existing therapies on secondary prevention and functional recovery are warranted.
•MS patients have extremely low levels of fitness regardless of levels of disability.•Poor cardiorespiratory fitness in MS associated with increased GABAergic intracortical inhibition.•Increased ...GABAergic intracortical inhibition may explain exacerbated feelings of MS fatigue.
Poor fitness among people with Multiple Sclerosis (MS) aggravates disease symptoms. Whether low fitness levels accompany brain functioning changes is unknown.
MS patients (n = 82) completed a graded maximal exercise test, blood was drawn, and transcranial magnetic stimulation determined resting and active motor thresholds, motor evoked potential latency, and cortical silent period (CSP).
Sixty-two percent of participants had fitness levels ranked below 10th percentile. Fitness was not associated with disability measured using the Expanded Disability Status Scale (EDSS). Regression analyses revealed that, cardiorespiratory fitness, when controlling for disease demographics, contributed 23.7% (p < 0.001) to the model explaining variance in CSP. Regression analysis using cardiorespiratory fitness and CSP as predictors showed that CSP alone explained 19.9% of variance in subjective fatigue (p = 0.002). Tumor necrosis factor was not associated with any variable.
Low fitness was associated with longer CSP in MS. Longer CSP was, in turn, related to greater MS fatigue.
MS patients had extremely low levels of cardiorespiratory fitness. Poor fitness predicted longer CSP, a marker of greater intracortical inhibition, which was linked to MS fatigue. Future research should examine whether aerobic training could shorten CSP and potentially lessen inhibition of cortical networks.
Adequate cardiorespiratory fitness is critical for firefighters since an insufficient level of fitness threatens the integrity of their operations and could be dangerous for their lives. In fact, the ...leading cause of mortality for on-duty firefighters is not injury but sudden cardiac death. Therefore, to mitigate these risks, potential firefighter recruits are often required to perform a graded exercise test to determine their cardiorespiratory fitness as part of the recruitment process. However, there are currently limited data available to prospective firefighters on the amounts and types of exercises needed to be successful in the graded exercise test, commonly known as a V̇O
test. Physiological parameters for the current secondary analysis were collected on firefighter applicants who performed the graded exercise test where 72% were successful and 28% were unsuccessful to meet the minimum standard set at 42.5 ml kg
min
. Prior to their test, applicants were asked to describe their exercise training routine by indicating the number of minutes per week spent exercising. Activities were then divided into one of two categories: endurance exercise or strength and power exercise training. The total exercise training describes the sum of all activities performed each week. The sum of endurance exercise activities and the sum of strength and power exercise activities were compared between the successful and the unsuccessful groups and results showed that successful applicants had a higher training volume and performed more endurance exercise training as compared to unsuccessful applicants. Therefore, practical recommendations related to exercise training regime are presented for firefighter applicants to embrace as guidance to prepare for their graded exercise test as part of their recruitment process.
Background and Purpose Previous research suggests that patients receiving inpatient stroke rehabilitation are sedentary although there is little data to confirm this supposition within the Canadian ...healthcare system. The purpose of this cross-sectional study was to observe two weeks of inpatient rehabilitation in a tertiary stroke center to determine patients' activity levels and sedentary time.
Methods Heart rate (HR) and accelerometer data were measured using an Actiheart monitor for seven consecutive days, 24 h/day, on the second week and the last week of admission. Participants or their proxies completed a daily logbook. Metabolic equivalent (MET) values were calculated and time with MET < 1.5 was considered sedentary. The relationship between patient factors (disability, mood, and social support) and activity levels and sedentary time were analyzed.
Results Participants (n = 19; 12 males) spent 10 h sleeping and 4 h resting each day, with 86.9% of their waking hours sedentary. They received on average 8.5 task-specific therapy sessions; substantially lower than the 15 h/week recommended in best practice guidelines. During therapy, 61.6% of physical therapy and 76.8% of occupational therapy was spent sedentary. Participants increased their HR about 15 beats from baseline during physical therapy and 8 beats during occupational therapy. There was no relationship between sedentary time or activity levels and patient factors.
Discussion Despite calls for highly intensive stroke rehabilitation, there was excessive sedentary time and therapy sessions were less frequent and of lower intensity than recommended levels.
Conclusions In this sample of people attending inpatient stroke rehabilitation, institutional structure of rehabilitation rather than patient-related factors contributed to sedentary time.
Objectives: Our objectives were: 1) to determine whether maximal aerobic exercise increased serum neurotrophins in chronic stroke and 2) to determine the factors that predict resting and ...exercise-dependent levels.
Methods: We investigated the potential predictors of resting and exercise-dependent serum insulin-like growth factor-1 and brain-derived neurotrophic factor among 35 chronic stroke patients. Predictors from three domains (demographic, disease burden, and cardiometabolic) were entered into 4 separate stepwise linear regression models with outcome variables: resting insulin-like growth factor, resting brain-derived neurotrophic factor, exercise-dependent change in insulin-like growth factor, and exercise-dependent change brain-derived neurotrophic factor.
Results: Insulin-like growth factor decreased after exercise (p = 0.001) while brain-derived neurotrophic factor did not change (p = 0.38). Greater lower extremity impairment predicted higher resting brain-derived neurotrophic factor (p = 0.004, r
2
= 0.23). Higher fluid intelligence predicted greater brain-derived neurotrophic factor response to exercise (p = 0.01, r
2
= 0.18). There were no significant predictors of resting or percent change insulin-like growth factor-1.
Discussion: Biomarkers have the potential to characterize an individual's potential for recovery from stroke. Neurotrophins such as insulin-like growth factor-1 and brain-derived neurotrophic factor are thought to be important in neurorehabilitation; however, the factors that modulate these biomarkers are not well understood. Resting brain-derived neurotrophic factor and percent change in brain-derived neurotrophic factor were related to physical and cognitive recovery in chronic stroke, albeit weakly. Insulin-like growth factor-1 was not an informative biomarker among chronic stroke patients. The novel finding that fluid intelligence positively correlated with exercise-induced change in brain-derived neurotrophic factor warrants further research.
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