Light Intensity Exercise Research Articles

Effects of Different Intensity Aerobic Exercise on Circulating Levels of Neurotrophic Factor in Healthy and Hyperlipidemic Adults in A Local Population

Objective: The present study is to compare the pre and post serum BDNF levels in healthy and hyperlipidemic population at baseline and post 12 weeks of exercise and to correlate the pre and post serum BDNF levels in healthy and hyperlipidemic population at baseline and post 12 weeks of exercise.
 Study Design: Two arm follow up non-blinded randomized controlled trial (RCT).
 Place and Duration of Study: Physiology department, Basic Medical Science Institute (BMSI), Jinnah Post-Graduate Medical Center (JPMC), Karachi
 Methodology: A total 258 participants of any age were divided into two groups: 129 participants in one of the two groups, Group-1 adult hyperlipidemic group and Group-2 healthy adults group. Both groups were additional divided into 3 subgroups with different exercise intensity i.e. light, moderate and high intensity exercise. To evaluate the health status of participants, graded exercise test by using Bruce protocol and the HRmax was performed and given a specific exercise program for 12 weeks. The test was a conducted as per Bruce protocol (Smith 2013), using a treadmill with heart rate monitoring and ECG monitor. Blood sample had been taken for the analysis of total cholesterol and serum levels of BDNF.
 Results: Mean levels of brain derived neurotropic factor (BDNF) of healthy and hyperlipidemic participants in all three different intensity exercise group (A, B, and C) at baseline and three follow-ups shown no statistically significant difference between LIEG on BDNF level from baseline (day zero) till three consecutive follow ups (p>0.05). While, in moderate (p<0.05) and high intensity participants (p<0.01) demonstrated an increase in BDNF levels at 90th day when compared from baseline i.e. day zero. Prominently, no significant difference observed at baseline (p>0.05), however a significant difference was found at day 30, 60 and 90 (p <0.05, 20.01, <0.001) respectively.
 Conclusion: In light of our findings we conclude that 12 weeks of moderate to high intensity exercise progress cognitive function, serum BDNF levels, and improved lipid profile parameters, while low intensity exercise showed no significant mean difference for healthy participants.

Wii or Kinect? A Pilot Study of the Exergame Effects on Older Adults' Physical Fitness and Psychological Perception.

Exergames are now often implemented among older adults for health purposes. This study aimed to investigate whether playing Kinect and Wii exergames has effects on older adults’ physical fitness and psychological perceptions towards exergames. A total of 23 older participants aged above 60 years were recruited and randomly assigned into two groups, in which they played either Kinect or Wii Bowling exergames for three sessions in one week. Physiological and psychological measures were collected including heart rate, blood pressure, shoulder flexibility, as well as perceived benefits and intentions for future use. Findings indicated that exergames are equivalent to light-intensity exercises, and hence pose no or minimal risk to older adults. Older adults had a positive attitude towards exergames and have a strong willingness to engage in exergaming on a regular basis. Although no significant platform difference was identified, observation and qualitative findings suggested that Wii might provide a more intense physical activity than Kinect, while Kinect might obtain a higher perception among older adults than Wii. The study has several practical implications for both health professionals and exergame designers targeting the ageing population.

Investigating Cortical Buffering Effects of Acute Moderate Intensity Exercise: A cTBS Study Targeting the Left Dorsolateral Prefrontal Cortex.

Background: The beneficial effects of both single-session bouts of aerobic exercise and therapeutic exercise interventions on the cortical regions associated with top-down attentional control [i.e., prefrontal cortex (PFC)] have been well documented. However, it remains unclear whether aerobic exercise can be used to buffer against suppressive influences on the dorsolateral PFC (dlPFC).Objective: The current study sought to determine whether a single session of moderate intensity aerobic exercise can offset the expected suppressive effects of continuous theta burst stimulation (cTBS) targeting the dorsolateral prefrontal cortex (dlPFC).Methods: Twenty-two right-handed participants (aged 19–30) completed a 20-minute movement-only control session [10% heart rate reserve (HRR)] and moderate intensity (50% HRR) exercise in a counterbalanced order. Following each exercise session, participants received active cTBS to the left dlPFC. Changes in executive functions were quantified using a Flanker paradigm employed at baseline, post-exercise and post-cTBS time points. Additionally, EEG was used to measure changes in event-related potential components related to inhibitory control (i.e., N2) and attentional control (i.e., P3) during the flanker task.Results: Behavioral results from the flanker task revealed a significant improvement in task performance following an acute bout of moderate intensity exercise. Furthermore, the effect of cTBS in both the movement-only control and moderate intensity conditions were non-significant. Similarly, EEG data from P3b and N2 ERP components revealed no changes to amplitude across time and condition. P3b latency data revealed a significant effect of time in both the moderate intensity and movement-only conditions, such that P3b latencies were significantly shorter across time points. Latency data within the N2 ERP component revealed no significant interactions or main effects.Conclusion: The findings of the current study provide tentative support for the hypothesis that both moderate and light intensity exercise promote cortical buffering against the suppressive effects of cTBS targeting the dlPFC. However, in the absence of a no-movement control, a lack of expected suppressive effects of cTBS cannot be ruled out.

Exercise Behaviors and Beliefs Among Pregnant Women in Rural Communities.

The purpose of this study is to examine beliefs and behaviors regarding exercise during pregnancy in pregnant and postpartum women living in rural communities. Surveys were distributed in healthcare settings and via social media to pregnant and postpartum (< 3months) women living in rural communities. Seventy-five women (28.1 ± 5.4year) participated. Nearly all believed light (96%) and moderate (89%) intensity exercise are safe to perform during pregnancy, while fewer agreed vigorous intensity (52%) or resistance (40%) exercise is safe. Most (88%) believed women can continue their exercise regimen, and 73% believed that previously inactive women can begin training while pregnant. Only one-third of women met recommendations for cardiorespiratory exercise. The majority (66%) never engaged in vigorous exercise, and most (73%) did not participate in resistance exercise. Pregnant women in rural communities participate in light intensity exercise, but are largely not meeting guidelines for aerobic or resistance training. Knowledge related to safe exercises, particularly resistance training, during pregnancy is limited. Targeted education and programmatic planning are needed in this population regarding exercise guidelines.

Dynamics of Fat Oxidation from Sitting at Rest to Light Exercise in Inactive Young Humans.

Societal erosion of daily life low-level physical activity has had a great influence on the obesity epidemic. Given that low fat oxidation is also a risk factor for obesity, we investigated, in a repeated measures design, the dynamics of fat oxidation from a resting state to a light-intensity leg cycling exercise (0–50 watts) in inactive, healthy young adults. Using indirect calorimetry, energy expenditure and the respiratory quotient (RQ) were assessed in a sitting posture at rest and during a cycling exercise in 35 subjects (20 women). The rate of perceived exhaustion (RPE) was assessed using the Borg Scale. During graded leg cycling, the mean RPE did not exceed values corresponding to the exercise being perceived as ‘light’. However, analysis of individual data at 50 watts revealed two distinct subgroups among the subjects: those having RPE values corresponding to the exercise being perceived as ‘very light to light’ and showing no increase in RQ relative to resting levels, as opposed to an increase in RQ in those who perceived the exercise as being ‘somewhat hard to hard’ (p < 0.001). Our study in inactive individuals showing that high fat oxidation was maintained during ‘light-perceived’ physical activity reinforced the potential importance of light physical activity in the prevention of obesity.

Aerobic exercise and consolidation of fear extinction learning among women with posttraumatic stress disorder

This study tested whether aerobic exercise delivered during the consolidation window following fear extinction learning reduces the return of fear among women with posttraumatic stress disorder (PTSD). Participants (n=35) completed an initial clinical assessment followed by a 3-day fear acquisition, extinction, and recall protocol. On day 1, participants completed a fear acquisition training task in which one geometric shape (conditioning stimulus; CS+) was paired (with 50% probability) with a mild electric shock (unconditioned stimulus; US), while a different shape (CS-) was never paired with the US. On day 2 (24 h later), participants completed a fear extinction training task in which the CS+ no longer predicted administration of the US. Shortly following extinction, participants were randomly assigned to complete either moderate-intensity aerobic exercise (EX) or a light-intensity exercise control (CON) condition. On day 3 (24 h later), participants completed fear recall tests assessing the return of fear (spontaneous recovery, renewal, and reinstatement). Fear responding was assessed via threat expectancy ratings and skin conductance responses (SCR). In the threat expectancy ratings, there were no significant differences between groups in spontaneous recovery; however, EX significantly (p=.02) reduced threat expectancy ratings following reinstatement relative to CON. In SCR measures, there were no significant differences between groups in spontaneous recovery, renewal, or reinstatement. These results support a role for moderate-intensity aerobic exercise during the consolidation window in reducing threat expectations following reinstatement in women with PTSD. Research should continue to examine exercise as a potential method for improving the efficacy of exposure-based therapies. Trial registrationClinicalTrials.gov Identifier: NCT04113798.

Does Exercise Influence the Susceptibility to Arterial Thrombosis? An Integrative Perspective.

Arterial thrombosis is the primary cause of death worldwide, with the most important risk factors being smoking, unhealthy diet, and physical inactivity. However, although there are clear indications in the literature of beneficial effects of physical activity in lowering the risk of cardiovascular events, exercise can be considered a double-edged sword in that physical exertion can induce an immediate pro-thrombotic environment. Epidemiological studies show an increased risk of cardiovascular events after acute exercise, a risk, which appear to be particularly apparent in individuals with lifestyle-related disease. Factors that cause the increased susceptibility to arterial thrombosis with exercise are both chemical and mechanical in nature and include circulating catecholamines and vascular shear stress. Exercise intensity plays a marked role on such parameters, and evidence in the literature accordingly points at a greater susceptibility to thrombus formation at high compared to light and moderate intensity exercise. Of importance is, however, that the susceptibility to arterial thrombosis appears to be lower in exercise-conditioned individuals compared to sedentary individuals. There is currently limited data on the role of acute and chronic exercise on the susceptibility to arterial thrombosis, and many studies include incomplete assessments of thrombogenic clotting profile. Thus, further studies on the role of exercise, involving valid biomarkers, are clearly warranted.

Cardiopulmonary responses during dynamic squatting exercise with and without whole-body vibration in adolescents

BACKGROUND: Whole-body vibration (WBV) has been widely used as a therapeutic resource in pediatric rehabilitation. However, the cardiopulmonary responses are still unknown. OBJECTIVE: To investigate the intensity of dynamic squatting exercise with and without WBV in healthy adolescents in order to characterize cardiorespiratory responses. METHODS: This was a quasi-experimental study. Twenty-five adolescents (14.1 ± 1.7 years), 10 girls and 15 boys, underwent to oxygen consumption (VO2) and heart rate (HR) assessments during a protocol of squatting with and without vibration. Inclusion criteria were age between 12 and 18 years old of both sexes, have normal weight according to BMI. Exclusion criteria were to present chronic or acute, neurological, orthopedic, respiratory, cardiac and endocrine disease and no self-reported contraindication for WBV (i.e. deep vein thrombosis, metal implants, pacemaker, epilepsy, tumors, arterial aneurysm, or arrhythmia). RESULTS: WBV was able to significantly increase VO2, HR and perceived exertion during squatting exercise when compared to rest and squatting without-WBV. WBV associated with squatting reached 24.7% of the VO2max and 56% of the HRmax predicted for age. Subjects during WBV reported a perceived exertion score between somewhat hard and hard compared to between very light and light in the Without-WBV protocol. CONCLUSION: Squatting associated to WBV was considered a light intensity exercise that can be tolerated by healthy adolescents. This study provided valid results of this training modality and could be used as a tool to define the energy consumption spent in this training modality.

Low levels of fine particulate matter increase vascular damage and reduce pulmonary function in young healthy adults

BackgroundFine particulate matter (PM2.5) related mild inflammation, altered autonomic control of cardiovascular function, and changes to cell function have been observed in controlled human exposure studies.MethodsTo measure the systemic and cardiopulmonary impacts of low-level PM exposure, we exposed 20 healthy, young volunteers to PM2.5, in the form of concentrated ambient particles (mean: 37.8 μg/m3, SD 6.5), and filtered air (mean: 2.1 μg/m3, SD 2.6). In this double-blind, crossover study the exposure order was randomized. During the 4 h exposure, volunteers (7 females and 13 males) underwent light intensity exercise to regulate ventilation rate. We measured pulmonary, cardiac, and hematologic end points before exposure, 1 h after exposure, and again 20 h after exposure.ResultsLow-level PM2.5 resulted in both pulmonary and extra-pulmonary changes characterized by alterations in systematic inflammation markers, cardiac repolarization, and decreased pulmonary function. A mean increase in PM2.5 concentration (37.8 μg/m3) significantly increased serum amyloid A (SAA), C-reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1), 1 h after exposure by 8.7, 9.1, 10.7, and 6.6%, respectively, relative to the filtered air control. SAA remained significantly elevated (34.6%) 20 h after PM2.5 exposure which was accompanied by a 5.7% decrease in percent neutrophils. Decreased pulmonary function was observed 1 h after exposure through a 0.8 and 1.2% decrease in forced expiratory volume in 1 s (FEV1) and FEV1/ forced vital capacity (FEV1/FVC) respectively. Additionally, sex specific changes were observed in repolarization outcomes following PM2.5 exposure. In males, P-wave and QRS complex were increased by 15.4 and 5.4% 1 h after exposure.ConclusionsThis study is the first controlled human exposure study to demonstrate biological effects in response to exposure to concentrated ambient air PM2.5 particles at levels near the PM2.5 US NAAQS standard.Clinical trial registration informationclinicaltrials.gov; Identifier: NCT03232086. The study was registered retrospectively on July 25, 2017, prior to final data collection on October 25, 2017 and data analysis.

Exercise for Maintaining Immunity during the COVID-19 Pandemic

Immune strength is one of the vital factors when a specific medicine or vaccine has not been developed. Although people may not be exercising enough owing to the “Stay Home” policy aimed at preventing the spread of infection, the decrease in daily physical activity will lead to increased incidence of metabolic syndrome and chronic inflammation. On the other hand, exhaustive exercise/training induces stress hormones and immunosuppressive cytokines, both of which reduce immune functions. Therefore, exercises aimed at enhancing immune strength should be of moderate intensity, ranging from light-intensity exercises to those that border on getting individuals out of breath within an hour; they are to be practiced more than three times per week for physical training adaptation.

Long-time follow up of physical activity level among older adults with rheumatoid arthritis

BackgroundPhysical activity and exercise are acknowledged as important parts in the management of rheumatoid arthritis (RA). However, long-term maintenance of exercise is known to be difficult. The aim of this study was to evaluate change in physical activity and physical fitness after four years in older adults with RA who had previously participated in exercise with person-centred guidance compared to controls.MethodA follow-up study was performed where older adults (> 65 years) who had participated in a randomized controlled trial where they were allocated to either exercise with person-centred guidance or home-based, light-intensity exercise (controls) were invited to one visit and assessed with performance-based test, blood-sampling and self-reported questionnaires. Forty-seven out of 70 older adults accepted participation, 24 from the exercise group and 23 from the control group. Comparisons of the result with baseline values were performed and explanatory factors for increase of physical activity were examined with logistic regression.ResultsThe result show that there was no significant difference in weekly hours of physical activity when groups where compared. However, participants in the exercise group rated significantly increased weekly hours of physical activity after four years (p = 0.004) when compared to baseline. Higher levels of fatigue, BMI and physical activity, at baseline were negatively associated with increased physical activity after four years. There was no significant difference in change of physical fitness between the groups. Within group analysis showed that the control group reported increased pain (p = 0.035), fatigue (p = 0.023) increased number of tender joints (p = 0.028) higher disease activity (p = 0.007) and worsening of global health (p = 0.004) when compared to baseline while the exercise group remained at the same level as at baseline.ConclusionThese results indicate that introducing moderate- to high intensity exercise with person-centred guidance might favor increased physical activity after four years in older adults with RA. Previous partaking in moderate- to high intensity exercise might also be protective against increased disease activity, pain and fatigue over time.

Low muscle mass impairs fat utilization during light-intensity exercise in Chinese men.

Age-related loss of the muscle mass is linked to obesity and diabetes because the muscle is the major site for fat oxidation which is influenced by exercise. We aimed to explore the association between fat oxidation rates (FORs) and exercise intensity during age-related muscle loss. A total of 224 healthy Chinese men aged 23-92 years were recruited. Fat and lean tissue masses were measured by DXA. The subjects were also tested using graded incremental exercise with an increased intensity of 10 W until maximal fat oxidation rate (Fatmax) was achieved. Real-time contribution (%) of fat to total energy expenditure were determined using indirect calorimetry. We found that appendicular skeletal muscle mass/weight (ASM/Wt) decreased during ageing and positively correlated with FORs during low-intensity exercise. In multiple linear regression models, FORs was positively related with ASM/Wt (β =0.446, P=0.0091) but negatively associated with exercise intensity (β =-0.573, P<0.0001), whereas fat oxidation rate did not show any association with age. Moreover, there was a significantly negative correlation between ASM/Wt and Fatmax. Our findings highlight the importance of muscle mass in fat utilization during low-intensity exercise. A higher exercise intensity indicated by Fatmax is recommended for improving fat oxidation in Chinese men with decreased muscle mass.

Walking With Leg Blood Flow Restriction: Wide-Rigid Cuffs vs. Narrow-Elastic Bands.

BackgroundBlood flow restriction (BFR) training is becoming a popular form of exercise. Walking exercise in combination with pressurized wide-rigid (WR) cuffs elicits higher cardiac workload and a vascular dysfunction due presumably to reperfusion injury to the endothelium. In contrast, narrow-elastic (NE) BFR bands may elicit different hemodynamic effects. Therefore, we compared the acute cardiovascular responses to two distinct forms of BFR training during light-intensity exercise.Methods and Results15 young healthy participants (M = 9, F = 6) performed five bouts of 2-min walking intervals at 0.9 m/s with a 1-min rest and deflation period with either WR, NE, or no bands placed on upper thighs. Cuff pressure was inflated to 160 mmHg in WR cuffs and 300 mmHg in NE bands while no cuffs were used for the control. Increases in heart rate and arterial blood pressure were greater (p < 0.05) in the WR than the NE and control conditions. Double product increased to a greater extent in the WR than in the NE and control conditions. Increases in perceived exertion and blood lactate concentration were greater (p < 0.05) in the WR compared with the NE and control conditions (p < 0.05), while no differences emerged between the NE and control conditions. There were no changes in arterial stiffness or brachial artery flow-mediated dilation (FMD) after all three trials.ConclusionUse of WR BFR cuffs resulted in a marked increase in blood pressure and myocardial oxygen demand compared with NE BFR bands, suggesting that NE bands present a safer alternative for at-risk populations to perform BFR exercise.Clinical Trial RegistrationThis study was registered in the Clinicaltrials.gov (NCT03540147).

Cytokine responses across submaximal exercise intensities in women with major depressive disorder

BackgroundMajor depressive disorder (MDD) is associated with chronic inflammation. Exercise training can treat depression in adults with MDD, potentially through reducing inflammatory activity. This improvement may occur through adaptations to repeated acute inflammatory responses. Cytokine responses to acute steady-state exercise of varying intensities were determined in women with different levels of depression. MethodsThis analysis included 19 women with MDD who each participated in four sessions consisting of 30 ​min of quiet rest, light, moderate, or hard intensity exercise. Blood samples were collected pre- and within 10 ​min post-session. Changes in the levels of IL-6, IL-8, IL-10, and TNF were evaluated in each session. ResultsSerum concentrations of IL-6, IL-8 and TNF were all significantly elevated following vigorous exercise (i.e., hard) compared to the quiet rest session. No changes in cytokine levels occurred after light and moderate exercise. Depression severity did not appear to influence the acute inflammatory response to exercise. LimitationsThe sample size was small, all female, and from a secondary data analysis, which limits the generalizability of the findings. ConclusionsRepeat, acute increases in inflammatory activity following hard exercise sessions may prompt adaptations and lead to reductions in chronic inflammation over time. This dose-response study identified an exercise intensity threshold to induce acute inflammatory responses in women with MDD.

Repeated hyperthermia exposure increases circulating Brain Derived Neurotrophic Factor levels which is associated with improved quality of life, and reduced anxiety: A randomized controlled trial

Hyperthermia is known to be beneficial to patients affected by various diseases. Brain Derived Neurotrophic Factor (BDNF) is a marker of neuroplasticity usually increased as response to acute exposure to human body stressors. Little is known about BDNF changes after repeated exposure to hyperthermia. To investigate the effect of a repeated hyperthermia exposure programme (HTC) on serum BDNF in healthy humans. Randomized, single-blind, controlled trial in healthy humans conducted at Sechenov University Physiology Laboratory between December 2016 and November 2018. The treatment period was 10 weeks. Researchers analysing serum BDNF and questionnaires data were blinded to participants allocation. Were 34 healthy male (age 20.2±1.6 years). Repeated Hyperthermia exposure programme, HTC, versus Light Intermittent Exercise, LIE, programme as control (10 weeks). Change in BDNF from baseline to final visit three days after treatment completion. 25 participants were analyzed. One participant withdrew before signing the informed consent and 8 participants (n=3 in HTC and n=5 in LIE) could not undertake the first assessment and were excluded. Mean change in BDNF was higher in HTC group vs LIE after both time points (after 12 and after 24 sessions). After 24 sessions BDNF was 30170 (SD 5268) pg/ml in HTC group a value that was significantly higher than 24104 (SD 2876) pg/ml measured in LIE group. BDNF concentrations were significantly higher than baseline values in HTC group only, 30170 (SD 5268) vs 26710 (SD 5437) pg/ml. A 10-week programme consisting of repeated exposure to hyperthermia resulted in a significantly higher increase of circulating BDNF compared to a programme consisting of intermittent light intensity exercise.

EXERCISE ACUTELY IMPROVES COGNITION IN HEALTHY OLDER ADULTS: THE ROLE OF AROUSAL

Previous researchers have reported that aerobic exercise improves cognition in older adults; however, few researchers have examined the role of arousal on improvements in cognition after exercise. The purpose of this study was to understand how changes in arousal acutely affect changes in cognitive performance after a single session of light compared to moderate intensity aerobic exercise. Cognitively normal older adults (N = 34) were enrolled in a randomized controlled trial where they were asked to complete the N-back task with faces, a cognitive task used to test working memory, in an fMRI scanner. On separate days, the task was completed before and 15 to 20 minutes after light and moderate intensity exercise. An intervention was also completed, but our question focuses on the acute effects of exercise rather than training. Arousal was measured before and after exercise through a questionnaire and a direct measure of physiological activation of the sympathetic nervous system with galvanic skin response (GSR). On average, resting GSRs decreased from pre- to post-exercise scan; however, the change was not statistically significant. The decrease in arousal after light exercise indicated that older adults had decreased sympathetic activity after both light and moderate intensity exercise. By contrast, N-back task performance improved most after moderate compared to light intensity exercise. Together, evidence that sympathetic activity tended to decrease generally for both intensities, whereas cognitive improvements were more specific, suggests that changes in arousal at rest were not a critical factor connecting exercise and improved working memory in this study.

Light aerobic exercise modulates executive function and cortical excitability.

Single bouts of aerobic exercise can modulate cortical excitability and executive cognitive function, but less is known about the effect of light-intensity exercise, an intensity of exercise more achievable for certain clinical populations. Fourteen healthy adults (aged 22 to 30) completed the following study procedures twice (≥7days apart) before and after 30min of either light aerobic exercise (cycling) or seated rest: neurocognitive battery (multitasking performance, inhibitory control and spatial working memory), paired-pulse TMS measures of cortical excitability. Significant improvements in response times during multitasking performance and increases in intracortical facilitation (ICF) were seen following light aerobic exercise. Light aerobic exercise can modulate cortical excitability and some executive function tasks. Populations with deficits in multitasking ability may benefit from this intervention.

A preliminary investigation of acute exercise intensity on memory and BDNF isoform concentrations

Little is known about the biological mechanisms underlying the beneficial effect of acute exercise on memory or the influence of single nucleotide polymorphisms (SNPs) on this effect. Brain-derived neurotrophic factor (BDNF) is a putative biological mechanism, and while findings from human studies are equivocal, they have neglected to assess how exercise affects individual BDNF isoform (proBDNF, mBDNF) concentrations in serum or the influence of the BDNF val66met SNP on BDNF isoform concentrations. Therefore, the objective of this study was to conduct an exploratory assessment of the effect of acute exercise intensity on memory performance and BDNF isoform concentrations relative to carrier status of the BDNF val66met SNP met allele and to provide guidance for future, fully-powered trials. Memory and BDNF isoform concentrations were assessed in three exercise groups (light intensity, vigorous intensity, and non-exercise) relative to BDNF met carrier status. Analyses revealed that BDNF isoform concentrations and memory were differentially affected by exercise intensity and BDNF met carrier status. Vigorous intensity exercise increased mBDNF, and BDNF met carriers had lower mBDNF concentration. Light intensity exercise improved memory, and over 24 h, memory was worse for BDNF met carriers. Implications from this work will help direct future mechanistic studies of the exercise-memory relationship.

Thermal behavior alleviates thermal discomfort during steady-state exercise without affecting whole body heat loss.

We tested the hypothesis that thermal behavior resulting in reductions in mean skin temperature alleviates thermal discomfort and mitigates the rise in core temperature during light-intensity exercise. In a 27 ± 0°C, 48 ± 6% relative humidity environment, 12 healthy subjects (6 men, 6 women) completed 60 min of recumbent cycling. In both trials, subjects wore a water-perfused suit top continually perfusing 34 ± 0°C water. In the behavior trial, subjects maintained their upper body thermally comfortable by pressing a button to perfuse cool water (2.2 ± 0.5°C) through the top for 2 min per button press. Metabolic heat production (control: 404 ± 52 W, behavior: 397 ± 65 W; P = 0.44) was similar between trials. Mean skin temperature was reduced in the behavior trial (by -2.1 ± 1.8°C, P < 0.01) because of voluntary reductions in water-perfused top temperature (P < 0.01). Whole body (P = 0.02) and local sweat rates were lower in the behavior trial (P ≤ 0.05). Absolute core temperature was similar (P ≥ 0.30); however, the change in core temperature was greater in the behavior trial after 40 min of exercise (P ≤ 0.03). Partitional calorimetry did not reveal any differences in cumulative heat storage (control: 554 ± 229, behavior: 544 ± 283 kJ; P = 0.90). Thermal behavior alleviated whole body thermal discomfort during exercise (by -1.17 ± 0.40 arbitrary units, P < 0.01). Despite lower evaporative cooling in the behavior trial, similar heat loss was achieved by voluntarily employing convective cooling. Therefore, thermal behavior resulting in large reductions in skin temperature is effective at alleviating thermal discomfort during exercise without affecting whole body heat loss.NEW & NOTEWORTHY This study aimed to determine the effectiveness of thermal behavior in maintaining thermal comfort during exercise by allowing subjects to voluntarily cool their torso and upper limbs with 2°C water throughout a light-intensity exercise protocol. We show that voluntary cooling of the upper body alleviates thermal discomfort while maintaining heat balance through convective rather than evaporative means of heat loss.

The Presence of Physical Symptoms in Patients With Tinnitus: International Web-Based Survey.

BackgroundTinnitus, or ringing in the ears, is a phantom perception of sound in the absence of overt acoustic stimulation. Many patients indicate that the perception of their tinnitus is not constant and can vary from moment to moment. This tinnitus fluctuation is one of the diagnostic criteria for somatosensory tinnitus (ST), a tinnitus subtype that is influenced by cervical spine or temporomandibular dysfunctions, although various factors have been reported to cause fluctuations in tinnitus, such as stress, anxiety, and physical activity.ObjectiveThe aim of this study was twofold: (1) to investigate the presence of physical symptoms in a large group of participants with tinnitus and (2) to investigate if these physical symptoms are more frequently present in a subgroup of participants with ST.MethodsA Web-based survey, questioning the presence of physical symptoms in a convenience sample of participants with tinnitus, was launched on the online forum, Tinnitus Talk, managed by Tinnitus Hub. After a general analysis of the physical symptoms present in our survey population, we further analyzed the group of participants who were diagnosed by a physician (n=1262). This subgroup was divided into 2 groups, one group diagnosed with ST and another group diagnosed with other types of tinnitus.ResultsIn total, 6115 participants with a mean age of 54.08 years (SD 13.8) completed the survey. Physical symptoms were frequently present in our sample of participants with tinnitus: 4221 participants (69.02%) reported some form of neck pain, 429 (7.01%) were diagnosed with temporomandibular disorders, 2730 (44.64%) indicated they have bruxism, and between 858 and 1419 (14.03%-23.20%) participants were able to modulate their tinnitus by voluntary movements. ST was diagnosed in 154 out of 1262 (12.20%) participants whose tinnitus cause was diagnosed by a physician. Symptoms referring to the known diagnostic criteria were evidently more present in the ST group than in the non-ST group. Additionally, participants with ST more often indicated a negative effect of a bad night’s sleep (P=.01) and light intensity exercise (P=.01).ConclusionsPhysical activity and movement (disorders) frequently affect tinnitus severity. Head-neck related symptoms are more frequently reported in the ST group, as is the ability to modulate the tinnitus by head or jaw movements. Additionally, participants with ST more often report fluctuations of their tinnitus and reaction to sleeping difficulties and low intensity exercise.