Self-reported effects of warm seasonal temperatures in persons with spinal cord injury.

OBJECTIVE: Spinal cord injury (SCI) interrupts motor, sensory, and autonomic pathways, impairing mobility and increasing heat storage during warm seasonal temperatures due to compromised autonomic control of vasodilation and sweating and recognition of body temperature. Thus, persons with SCI are more vulnerable to hyperthermia and its adverse effects. However, information regarding how persons with SCI perceive warmer seasons and whether thermal discomfort during warmer seasons restricts routine activities remains anecdotal. DESIGN: Cross-sectional, self-report surveys. SETTING: VA Medical Center and Kessler Institute for Rehabilitation. PARTICIPANTS: Three groups of 50 participants each: tetraplegia, paraplegia, and matched non-SCI controls. OUTCOME MEASURES: Tetraplegia, paraplegia, and control groups responded "yes" or "no" when asked whether warm seasonal temperatures adversely affected comfort or participation in routine activities. RESULTS: The percentage of responses differed among tetraplegia, paraplegia, and control groups when asked if they required ≥20 min to cool down once overheated (44 vs. 20 vs. 12%; X2 = 14.7, P < 0.001), whether heat-related discomfort limited their ability to go outside (62 vs. 34 vs. 32%; X2 = 11.5, P = 0.003), if they needed to use a water-mister because of the heat (70 vs. 44 vs. 42%; X2 = 9.8, P = 0.008), and if heat-related discomfort limited participation in social activities (40 vs. 20 vs. 16%; X2 = 8.7, P = 0.01). CONCLUSION: Warmer seasonal temperatures had a greater negative impact on reported comfort and daily activities of persons with SCI than non-SCI controls. Those with tetraplegia were most adversely affected. Our findings warrant increasing awareness and identifying interventions to address the vulnerability of persons with SCI to hyperthermia.

Core Temperature Lability Predicts Sympathetic Interruption and Cognitive Performance during Heat Exposure in Persons with Spinal Cord Injuries.

Among persons with high spinal cord injury (Hi-SCI: > T5), changes in core body temperature (Tcore) and cognitive performance during heat exposure appear related to degree of sympathetic interruption. Twenty men with Hi-SCI (C4-T4, American Spinal Injury Association Impairment Scale [AIS] A-B) and 19 matched, able-bodied controls were acclimated to 27°C baseline (BL) before exposure to 35°C heat challenge (HC). Two groups, differentiated by increase in Tcore during HC, were identified: high responders (HR-SCI: ΔTcore ≥0.5°C; n = 13, C4-T2) and low responders (LR-SCI: ΔTcore <0.5°C; n = 7, C4-T4). Tcore, distal skin temperatures (Tskavg), and distal microvascular perfusion (LDFboth feet) were measured, as were indices of sympathetic integrity, mean arterial pressure (MAP), and extremity sweat rate (SRavg). Cognitive performance was assessed at BL and post-HC, using the Stroop Color and Word and Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) Digit Span tests. At BL, Tcore of the HR-SCI group (36.6 ± 0.4°C) was lower than that for the LR-SCI (37.1 ± 0.3°C; p = 0.011) and control groups (37.3 ± 0.3°C; p < 0.001). After HC, Tcore was not different among groups. MAP of the HR-SCI group (70.9 ± 9.8 mm Hg) was lower than that of the LR-SCI (81.8 ± 7.0 mm Hg; p = 0.048) and control groups (89.9 ± 9.9 mm Hg; p < 0.001). SRavg increased more in the control group (77.0 ± 52.5 nL/cm2/min) than in the HR-SCI group (15.5 ± 22.0 nL/cm2/min; p = 0.001). Only the HR-SCI group had significant increases in T-Scores of Stroop Word (7.5 ± 4.4; p < 0.001), WAIS-IV Digit Span Sequence (1.9 ± 1.8; p = 0.002), and WAIS-IV Digit Span Total (1.4 ± 1.6; p = 0.008). Persons with SCI who responded to HC with a greater change in Tcore demonstrated evidence of greater sympathetic interruption and had an associated improvement in cognitive performance.

Effects of a Novel Rotator Cuff Rehabilitation Device on Shoulder Strength and Function.

ABSTRACT: Savitzky, JA, Abrams, LR, Galluzzo, NA, Ostrow, SP, Protosow, TJ, Liu, SA, Handrakis, JP, and Friel, K. Effects of a novel rotator cuff rehabilitation device on shoulder strength and function. J Strength Cond Res 35(12): 3355-3363, 2021-The glenohumeral joint, a multiaxial ball and socket joint, has inherent instability counterbalanced by the muscular stability of the rotator cuff (RC) and connective tissue. Exercise has been shown to alleviate pain and disability arising from degenerative changes of the RC due to overuse, trauma, or poor posture. This study compared the training effects of ShoulderSphere (SS), an innovative device that uses resistance to centrifugal force, to TheraBand (TB), a traditional device that uses resistance to elasticity. Thirty-five healthy male and female adults (24.2 ± 2.4 years) were randomized into 3 groups: SS, TB, and control. Five outcomes were assessed before and after the twice-weekly, 6-week intervention phase: strength (shoulder flexion [Fx], extension [Ext], external rotation [ER], and internal rotation [IR]), proprioception (6 positions), posterior shoulder endurance (ShEnd), stability (Upper Quarter Y-Balance Test [YBal] (superolateral [YBalSup], medial [YBalMed], and inferolateral [YBalInf]), and power (seated shot put [ShtPt]). Data were analyzed using a 3 (group: SS, TB, and control) × 2 (time: pre and post) generalized estimating equation. Analyses demonstrated a main effect of time for all strength motions (p < 0.01): YBalInf (p < 0.0001), ShtPt (p < 0.05), and ShEnd (p < 0.0001) but no interaction effects of group × time. There were no main or interaction effects for proprioception. Both SS and TB groups had significant within-group increases in Ext, IR, YBalInf, and ShEnd. Only the SS group had significant increases in ER, Fx, and ShtPt. ShoulderSphere demonstrated comparable conditioning effects with TB and may afford additional strength gains in Fx and ER, and power. ShoulderSphere should be considered a viable alternative in RC conditioning.

Participant-reported priorities and preferences for developing a home-based physical activity telemonitoring program for persons with tetraplegia: a qualitative analysis.

Study design: Focus group. Objectives: The purpose of this qualitative study was to explore perceptions and priorities of persons with spinal cord injury (SCI) for physical activity and to incorporate their feedback to inform future development of a physical activity program delivered via a telemonitoring platform. Setting: New York. Methods: Qualitative data were collected from a purposive sample of adults with tetraplegia (N = 7). Two investigators led an audio-recorded focus group using a moderator's guide. Data were analyzed using a six-phase thematic analysis approach. Results: The discussion focused on two major areas, which resulted in multiple derived themes and subthemes. The first theme centered on the daily life of persons with tetraplegia, including changes after SCI, gain of function prioritization, and identification of psychosocial support systems that facilitate community reintegration after injury. The second theme centered on participant perceptions and recommendations for a physical activity program delivered via a telemonitoring platform. Desired design features included variations in schedule, diverse activities, or exercises included in each class, and optional two-way video to enable social interactions with classmates. Conclusions: Participants favorably viewed the concept of a physical activity program delivered via a telemonitoring platform and contributed program design ideas. Although this was a small sample size, challenges to obtaining physical activity expressed by participants were consistent with those identified previously in larger studies of persons with tetraplegia. Therefore, we expect these concepts and their recommendations to be relevant to the greater SCI community.

Impact of passive heat stress on persons with spinal cord injury: Implications for Olympic spectators.

Environmental heat stress can negatively impact health, work capacity, and athletic performance and potentially to lead to life-threatening consequences if not mitigated. With the upcoming Toyko Olympic games to be held during anticipated warm ambient temperatures (up to 29°C), and with spectators potentially spending long durations of time outdoors, certain populations of persons with impaired thermoregulatory capacity will be at higher risk of heat-related illness from passive heat stress. Persons with spinal cord injury (SCI) are one of these groups as a result of a decentralized sympathetic nervous system, which leaves them with impairment in convective and evaporative cooling via vasodilation and sweating, respectively. This review summarizes (1) thermoregulatory physiological responses of persons with SCI under passive heat stress: the effect of level and completeness of injury; (2) the impact of passive heat stress on quality of life (QOL), outdoor participation, behavioral thermoregulation, and cognition; (3) recommendations and education for clinicians providing health care for persons with SCI; and (4) suggestions of future directions for exploring the gaps in the literature on passive heat stress in persons with SCI. This article aims to equip consumers with SCI and health-care professionals with the most up-to-date knowledge on passive heat stress responses in persons with SCI, so that their attendance at the Olympic games can be done with maximal safety and enjoyment.

Multimodal cortical and subcortical exercise compared with treadmill training for spinal cord injury.

BACKGROUND AND PURPOSE: Spared fibers after spinal cord injury (SCI) tend to consist predominantly of subcortical circuits that are not under volitional (cortical) control. We aim to improve function after SCI by using targeted physical exercises designed to simultaneously stimulate cortical and spared subcortical neural circuits. METHODS: Participants with chronic motor-incomplete SCI enrolled in a single-center, prospective interventional crossover study. Participants underwent 48 sessions each of weight-supported robotic-assisted treadmill training and a novel combination of balance and fine hand exercises, in randomized order, with a 6-week washout period. Change post-intervention was measured for lower extremity motor score, soleus H-reflex facilitation; seated balance function; ambulation; spasticity; and pain. RESULTS: Only 9 of 21 enrolled participants completed both interventions. Thirteen participants completed at least one intervention. Although there were no statistically significant differences, multimodal training tended to increase short-interval H-reflex facilitation, whereas treadmill training tended to improve dynamic seated balance. DISCUSSION: The low number of participants who completed both phases of the crossover intervention limited the power of this study to detect significant effects. Other potential explanations for the lack of significant differences with multimodal training could include insufficient engagement of lower extremity motor cortex using skilled upper extremity exercises; and lack of skill transfer from upright postural stability during multimodal training to seated dynamic balance during testing. To our knowledge, this is the first published study to report seated posturography outcomes after rehabilitation interventions in individuals with SCI. CONCLUSION: In participants with chronic incomplete SCI, a novel mix of multimodal exercises incorporating balance exercises with skilled upper extremity exercises showed no benefit compared to an active control program of body weight-supported treadmill training. To improve participant retention in long-term rehabilitation studies, subsequent trials would benefit from a parallel group rather than crossover study design.

The Effects of Aerobic Exercise and Gaming on Cognitive Performance.

The purpose of our study was to investigate the effects of video gaming, aerobic exercise (biking), and the combination of these two activities on the domains of cognitive performance: selective attention, processing speed, and executive functioning. The study was a randomized clinical trial with 40 subjects (mean age 23.7 ± 1.8 years) randomized to one of four thirty-minute conditions: video gaming, biking, simultaneous gaming and biking, and a control condition. Cognitive performance was measured pre and post condition using the Stroop test and Trails B test. A mixed design was utilized. While video gaming, biking, simultaneous gaming and biking conditions improved selective attention and processing speed (p < 0.05), only the bike condition improved the highest order of cognitive performance, executive function (p < 0.01). There were no changes in cognitive performance for the control condition. Previous studies have shown that if tasks approach the limits of attentional capacity there is an increase in the overall chance for errors, known as the dual-task deficit. Simultaneous biking and gaming may have surpassed attentional capacity limits, ultimately increasing errors during the executive function tests of our cognitive performance battery. The results suggest that the fatiguing effects of a combined physically and mentally challenging task that extends after the exercise cessation may overcome the eventual beneficial cognitive effects derived from the physical exercise.

Effect of Heat Exposure on Cognition in Persons with Tetraplegia.

Individuals with cervical spinal cord injury (SCI) have impaired thermoregulatory mechanisms attributed to interruption of motor, sensory, and autonomic neuropathways. To determine the effects of heat exposure on core body temperature (Tcore) and cognitive performance in persons with tetraplegia, 8 individuals with chronic tetraplegia (C3-C7, American Spinal Cord Injury Association Impairment Scale A-B) and 9 able-bodied controls were acclimated to 27°C at baseline (BL) before being exposed to 35°C for up to 120 min (Heat Challenge). Rectal temperature (Tcore), distal skin temperatures (Tskavg), sweat rate (QSavg), microvascular skin perfusion (LDFavg), and plasma norepinephrine (NE) were measured. Cognitive performance was assessed using Stroop Color and Word and Wechsler Adult Intelligence Scale-Fourth Edition Digit Span tests at BL and at the end of Heat Challenge. After Heat Challenge, Tcore increased 0.78 ± 0.18°C (p < 0.001) in tetraplegics after an average of 118 ± 5 min. Tcore did not change in controls after 120 min. The increase in QSavg was larger in controls than in tetraplegics (946 ± 672% vs. 51 ± 12%; p = 0.007, respectively). LDFavg increased only in controls (109 ± 93%; p = 0.008). Tskavg appeared to increase less in tetraplegics than in controls. Plasma NE levels remained lower in tetraplegics compared to controls after Heat Challenge (86 ± 64 vs. 297 ± 84 pg/mL, respectively; p < 0.001). Stroop Color, Interference, and WAIS-IV Sequence scores increased only in tetraplegics (19.4 ± 17.2%; p < 0.05, 8.3 ± 5.9%; p < 0.05, 29.1 ± 27.4%; p < 0.05, respectively). Dysfunctional thermoregulatory mechanisms in the tetraplegic group allowed Tcore to rise from subnormal levels to normothermia during heat exposure. Normothermia was associated with improvements in attention, working memory, and executive function.

Thermodysregulation in persons with spinal cord injury: case series on use of the autonomic standards.

INTRODUCTION: The ability to maintain core body temperature (Tcore) within a narrow range (37 ± 0.6 °C), despite exposure to a wide range of ambient temperatures, is essential in order to provide an optimal environment for vital organs, the central nervous system (CNS), and cellular processes to function. High-level (above T6) spinal cord injury (SCI) interrupts the autonomic nervous system's ability to carry out hypothalamic regulation of thermoregulatory mechanisms for both heat dissipation and conservation. This interruption leaves persons with high-level SCI vulnerable to hyper and hypothermia even during exposure to relatively mild ambient temperatures. The goal of the Autonomic Standards is to enable the clinician to quickly identify those individuals with SCI who may be most at risk for thermoregulatory dysfunction. CASE PRESENTATION: Case 1: Heat Exhaustion, Case 2: Heat Stroke in absence of CNS symptoms, Case 3: Heat Exhaustion. DISCUSSION: The three cases demonstrate the signs and symptoms that may accompany hyperthermia in persons with SCI. The onset may be quite rapid and the condition persistent, despite ambient temperatures being much less intense than expected to be necessary to induce similar conditions in able-bodied (AB) persons. The responses of the persons in the case studies to the temperature regulation and autonomic control of sweating sections of the Autonomic Standards would identify them as being vulnerable and warrant providing appropriate exposure guidelines and precautions to them and their caregivers.

Self-reported effects of cold temperature exposure in persons with tetraplegia.

OBJECTIVE: Cervical spinal cord injury (tetraplegia) is known to interrupt sympathetic vasculature control, thereby preventing shunting of blood from the periphery to central organs when exposed to cold temperatures. As a result, persons with tetraplegia are at risk to develop hypothermia. However, information regarding the discomfort experienced during the cooler months (late fall, winter, early spring) is overwhelmingly anecdotal. It is not known, with any certainty, how those with tetraplegia perceive cold and if discomfort in colder environments restricts them from performing activities that they routinely would perform. DESIGN: Prospective, two-group, self-report surveys. SETTING: VA Medical Center and Kessler Institute for Rehabilitation. PARTICIPANTS: Forty-four subjects with tetraplegia; 41 matched non-SCI controls. OUTCOME MEASURES: Tetraplegic and control groups responded "yes" or "no" when asked whether cold seasonal temperatures allowed comfort or negatively affected participation in routine activities. RESULTS: Percentage of responses of tetraplegia compared to controls was different as to whether they felt cold when others in the same room were comfortable (82 vs. 24%; χ2 = 28.2, P < 0.0001), felt comfortable outdoors (17 vs. 43%; χ2 = 6.8, P = 0.009), or whether cold negatively affected bathing routines (55 vs. 15%; χ2 = 14.8, P = 0.0001), keeping physician appointments (46 vs. 12%; χ2 = 11.3, P = 0.0008), thinking clearly (41 vs. 7%; χ2 = 12.9, P = 0.0003), and completing usual work duties (46 vs. 10%; χ2 = 13.3, P = 0.0003). CONCLUSION: Cold seasonal temperatures have a reported greater negative impact on personal comfort and ability to perform vital activities in persons with tetraplegia than that of non-SCI controls. These findings highlight the need to address thermoregulatory impairment in persons with tetraplegia.

Effect of Mild Cold Exposure on Cognition in Persons with Tetraplegia.

UNLABELLED: Persons with a cervical spinal cord injury (SCI) have impaired thermoregulatory mechanisms secondary to interrupted of motor, sensory, and sympathetic pathways. In this study, our primary aim was to determine the effect of cool temperature exposure on core body temperature (Tcore) and cognitive performance in persons with tetraplegia. Seven men with chronic tetraplegia (C3-C7, American Spinal Injury Association Impairment Scale [AIS] A-C) and seven able-bodied controls were exposed to 27°C temperature at baseline (BL) before being exposed to 18°C for ≤120 min (Cool Challenge). Rectal temperature (Tcore), distal skin temperatures (Tskavg), microvascular skin perfusion (LDFavg), and systolic blood pressure (SBP) were measured. Cognitive performance was assessed using Delayed Recall, Stroop Interference tests at the end of BL and Cool Challenge. After Cool Challenge, Tcore decreased -1.2±0.12°C (p<0.0001) in tetraplegics after an average of 109±15.9 min with no change in controls after 120 min. Tskavg declined in both groups, but decline was less in tetraplegics than in controls (-8.6±5.8% vs. -31.6±7.9%, respectively; p<0.0001). LDFavg declined only in controls (-72±17.9%; p<0.001). Plasma norepinephrine levels differed after Cool Challenge (tetraplegics vs. CONTROLS: 86±62 pg/mL vs. 832±431 pg/mL, respectively; p<0.01). SBP increased from BL to Cool Challenge only in controls (123±16 mm Hg to 149±17 mm Hg, respectively; p<0.01). Delayed Recall and Stroop Interference scores both declined in tetraplegics (-55±47.4%; p<0.05 and -3.9±3.8%; p<0.05, respectively), but not in controls. We conclude that persons with tetraplegia lack adequate thermoregulatory mechanisms to prevent downward drift in Tcore on exposure to cool temperatures. This decline in Tcore was associated with deterioration of working memory and executive function.

Cognition may be related to arterial pulsatility index in HD patients.

AIMS: Hemodialysis (HD) patients have a heavy burden of subclinical cerebrovascular disease and cognitive changes consistent with a vascular etiology. Pulsatility index is associated with microangiopathy of cerebral blood vessels and an increased risk of cerebral infarction. The proposed study was to determine common carotid artery pulsatility index (CCAPI) and its relation to cognition in well-dialyzed HD patients with no history of stroke or dementia and matched controls. METHODS: Observational, cross-sectional study of CCAPI and cognition in 37 hemodialysis outpatients and 18 matched controls with normal kidney function. Non-parametric analyses were used to compare variables between groups. Multiple regression and ANOVA models were used to adjust for risk factor differences. RESULTS: Controls had a lower CCAPI than the HD group (1.7 ± 0.3 vs. 2.1 ± 0.4 cm/s, p = 0.006). HD patients scored significantly lower on all cognitive domains. Attention correlated with CCAPI in HD patients, independent of hypertension, diabetes, hyperlipidemia, and years on HD (r2 = -0.36, p = 0.01). CCAPI correlated with years on HD, independent of traditional cardiovascular risk factors. (r2 = 0.26, p = 0.04). CONCLUSION: In well-dialyzed hemodialysis patients with no history of stroke or dementia, CCAPI may correlate with cognitive function and represent a marker for underlying cerebral microvascular disease.

Key characteristics of low back pain and disability in college-aged adults: a pilot study.

OBJECTIVE: To identify which factors commonly associated with low back pain (LBP) and disability differ between college-aged persons with LBP and with no or minimal LBP. DESIGN: Clinical measurement, observational study. Subjects were assessed for LBP with the visual analog scale (VAS) and for disability from LBP using the Oswestry Disability Index (ODI). Subjects were measured for variables commonly associated with LBP and were grouped by both VAS (minimum [min]/no pain, pain) and ODI (no disability, disability) scores. SETTING: College campus at a university. PARTICIPANTS: A convenience sample (N=84) of English-speaking students (34 men, 50 women) between 18 and 30 years of age. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Sports activity (sports activity score of the Baecke Physical Activity Questionnaire), depression, hamstring and hip flexor range of motion, low back extensor endurance, abdominal strength and endurance. RESULTS: A significant main effect of group was found for both pain (P=.019) and disability groups (P=.006). The min/no pain and pain groups differed in back endurance (114.2±38.8s vs 94.5±44.5s, respectively; P=.04). The no disability and disability groups differed in back endurance (116.3±35.9s vs 97.1±45.7s, respectively; P=.03) and the sports activity score of the Baecke Physical Activity Questionnaire (2.98±.95 vs 2.48±.85, respectively; P=.01). Subjects with hyperkyphotic postures compared with the normative thoracic group had higher depression scores (49 vs 38.5, respectively; P=.03) and less hamstring flexibility (30.5 vs 49.9, respectively; P<.001). CONCLUSIONS: Back extensor endurance was consistently different between both the pain and disability groups. Addressing limited low back extensor endurance and low levels of physical activity in young adults may have clinical relevance for the prevention and treatment of LBP and disability.

Fatiguing upper body aerobic exercise impairs balance.

Douris, PC, Handrakis, JP, Gendy, J, Salama, M, Kwon, D, Brooks, R, Salama, N, and Southard, V. Fatiguing upper body aerobic exercise impairs balance. J Strength Cond Res 25(12): 3299-3305, 2011-There are many studies that have examined the effects of selectively fatiguing lower extremity muscle groups with various protocols, and they have all shown to impair balance. There is limited research regarding the effect of fatiguing upper extremity exercise on balance. Muscle fiber-type recruitment patterns may be responsible for the difference between balance impairments because of fatiguing aerobic and anaerobic exercise. The purpose of our study was to investigate the effect that aerobic vs. anaerobic fatigue, upper vs. lower body fatigue will have on balance, and if so, which combination will affect balance to a greater degree. Fourteen healthy subjects, 7 men and 7 women (mean age 23.5 ± 1.7 years) took part in this study. Their mean body mass index was 23.6 ± 3.2. The study used a repeated-measures design. The effect on balance was documented after the 4 fatiguing conditions: aerobic lower body (ALB), aerobic upper body (AUB), anaerobic lower body, anaerobic upper body (WUB). The aerobic conditions used an incremental protocol performed to fatigue, and the anaerobic used the Wingate protocol. Balance was measured as a single-leg stance stability score using the Biodex Balance System. A stability score for each subject was recorded immediately after each of the 4 conditions. A repeated-measures analysis of variance with the pretest score as a covariate was used to analyze the effects of the 4 fatiguing conditions on balance. There were significant differences between the 4 conditions (p = 0.001). Post hoc analysis revealed that there were significant differences between the AUB, mean score 4.98 ± 1.83, and the WUB, mean score 4.09 ± 1.42 (p = 0.014) and between AUB and ALB mean scores 4.33 ± 1.40 (p = 0.029). Normative data for single-leg stability testing for this age group are 3.9 ± 1.9. Higher scores reflect greater balance deficits. The AUB condition produced the greatest balance deficit. Our data provide evidence of the important role of the upper body in maintaining unilateral standing balance and supports its inclusion as part of rehabilitation and training protocols designed to improve balance.

Comparison of 24-hour cardiovascular and autonomic function in paraplegia, tetraplegia, and control groups: implications for cardiovascular risk.

BACKGROUND: Fluctuations in 24-hour cardiovascular hemodynamics, specifically heart rate (HR) and blood pressure (BP), are thought to reflect autonomic nervous system (ANS) activity. Persons with spinal cord injury (SCI) represent a model of ANS dysfunction, which may affect 24-hour hemodynamics and predispose these individuals to increased cardiovascular disease risk. OBJECTIVE: To determine 24-hour cardiovascular and ANS function among individuals with tetraplegia (n=20; TETRA: C4-C8), high paraplegia (n=10; HP: T2-T5), low paraplegia (n=9; LP: T7-T12), and non-SCI controls (n=10). Twenty-four-hour ANS function was assessed by time domain parameters of heart rate variability (HRV); the standard deviation of the 5-minute average R-R intervals (SDANN; milliseconds/ms), and the root-mean square of the standard deviation of the R-R intervals (rMSSD; ms). Subjects wore 24-hour ambulatory monitors to record HR, HRV, and BP. Mixed analysis of variance (ANOVA) revealed significantly lower 24-hour BP in the tetraplegic group; however, BP did not differ between the HP, LP, and control groups. Mixed ANOVA suggested significantly elevated 24-hour HR in the HP and LP groups compared to the TETRA and control groups (P<0.05); daytime HR was higher in both paraplegic groups compared to the TETRA and control groups (P<0.01) and nighttime HR was significantly elevated in the LP group compared to the TETRA and control groups (P<0.01). Twenty-four-hour SDANN was significantly increased in the HP group compared to the LP and TETRA groups (P<0.05) and rMSSD was significantly lower in the LP compared to the other three groups (P<0.05). Elevated 24-hour HR in persons with paraplegia, in concert with altered HRV dynamics, may impart significant adverse cardiovascular consequences, which are currently unappreciated.

Effects of midodrine hydrochloride on blood pressure and cerebral blood flow during orthostasis in persons with chronic tetraplegia.

OBJECTIVE: To determine the mean arterial pressure (MAP) and middle cerebral artery mean blood flow velocity (MFV) responses to 5 and 10mg midodrine during head-up tilt (HUT) in persons with tetraplegia. DESIGN: Prospective dose-response trial. SETTING: James J. Peters Veterans Administration Medical Center. PARTICIPANTS: Persons (N=10) with chronic tetraplegia (duration of injury=23+/-11 y). INTERVENTION: A dose titration study was performed over 3 testing days: control (no drug), 5mg midodrine (5mg), or 10mg midodrine (10mg) during 30 minutes of baseline (predrug/no drug), 30 minutes of supine rest postdrug/no drug, 15 minutes of progressive HUT (5 minutes at 15 degrees , 25 degrees , 35 degrees ), and 45 minutes of 45 degrees HUT. MAIN OUTCOME MEASURES: MAP and MFV response to midodrine supine and during HUT. RESULTS: Ten milligrams of midodrine significantly increased MAP while supine and during the HUT maneuver. Of note, the mean increase in MAP during HUT with 10mg was a result of a robust effect in 2 persons, with minimal change in the remaining 8 study subjects. The reduction in cerebral MFV during HUT was attenuated with 10mg. CONCLUSIONS: These findings suggest that midodrine 10mg may be efficacious for treatment of hypotension and orthostatic hypotension in select persons with tetraplegia. Although midodrine is routinely prescribed to treat orthostatic hypotension, the results of our work suggests limited efficacy of this agent, but additional studies in a larger sample of subjects with spinal cord injury should be performed.

Static stretching does not impair performance in active middle-aged adults.

Recent investigations with young, healthy adult subjects suggest that static stretching before activity decreases performance and should, therefore, be avoided. The purpose of this study was to assess the effects of an acute static stretching protocol on balance and jump/hop performance in active middle-aged adults. Ten subjects (6 men and 4 women aged 40-60 yr) from a martial arts school volunteered to take part in this research study. This was a repeated measures design. Subjects who stretched for 10 minutes using a 30-second hold during 1 session sat quietly for 10 minutes during the alternate session. Sessions were randomly assigned. The following dependent variables were compared: Dynamic Stability Index (DSI) for single-leg dynamic balance (smaller DSI = improved balance); distances for broad jump, single hop, triple hop, and crossover hop; elapsed time for a 6-m timed hop. Group means for balance were significantly different between the stretch and no-stretch conditions (3.5 +/- 0.7 vs. 4.3 +/- 1.4 DSI, respectively; p < 0.05). No significant differences were found between the group means of the stretch and no-stretch conditions for the dependent measures of broad jump, single hop, triple hop, crossover hop, and 6-m timed hop performance. Ten minutes of acute static stretching enhances dynamic balance and does not affect jump/hop performance in active middle-aged adults. Static stretching should be included before competition and before exercise in fitness programs of active middle-aged adults.

Martial art training enhances the glutathione antioxidant system in middle-aged adults.

The purpose of this study was to compare the antioxidant capacity of physically active middle-aged martial artists to age-matched sedentary controls. Nine sedentary subjects (mean age 52.9 yr) and 9 martial artists (mean age 51.8 yr) who practice Soo Bahk Do, a Korean martial art and were age- and sex-matched performed a graded exercise test (GXT) using a modified Bruce protocol. Ages ranged from 41 to 58 years. A GXT has been shown to be an effective technique for inducing oxidative stress. Glutathione (GSH) is the body's most highly concentrated antioxidant, is the central component of the antioxidant system, and plays an essential role in protecting tissues against oxidative stress. Free radical oxidation leads to the transformation of GSH to glutathione disulfide (GSSG). Venous blood samples for GSH and GSSG were collected before and immediately after the GXT. Repeated measures analysis of variance were performed on the resting baseline values and immediate post-GXT values of GSH, GSSG, and GSH:GSSG to compare groups. The blood GSH, GSSG, and GSH:GSSG levels were significantly different (p < 0.001) between the 2 groups at rest and after the GXT. The Soo Bahk Do practitioners had higher resting levels of GSH and lower levels of GSSG and responded more effectively to acute oxidative stress than the age-matched sedentary controls. Soo Bahk Do appears to enhance the antioxidant defense system and may be an effective intervention for improving overall health by protecting against the adverse effects of oxidative stress that is associated with the free radical theory of aging. Health professionals should be aware of alternative methods of training, conditioning, and exercise that can improve the general adaptation response to oxidative stress.

Cold face test in persons with spinal cord injury: age versus inactivity.

INTRODUCTION: Persons with spinal cord injury (SCI) reflect a model of precocious aging and inactivity; as such, these individuals manifest well-appreciated cardiovascular abnormalities. We aimed to determine the influence of inactivity in persons with SCI, and the influence of age in healthy controls, on cardiovascular autonomic responses to the cold face test (CFT). METHODS: Subjects recruited (n = 42) included 18 controls: 10 young (25 +/- 2 years) and 8 old (50 +/- 6 years), and 24 subjects with chronic SCI: 17 with tetraplegia (C3-C8 44 +/- 7 years) and 7 with paraplegia (T5-T10 36 +/- 8 years). Heart rate (HR) and blood pressure were collected continuously: 2-min pre-CFT, 1-min CFT and 2-min post-CFT. Time-frequency (wavelet) analysis of HR (HFln) was used as an estimate of vagal cardiac modulation. RESULTS: The HR response to the CFT differed significantly among the SCI group (4.1 +/- 8.8 bpm) and the young (-7.7 +/- 5.9 bpm; P \ 0.001) and old (-6.8 +/- 10.7 bpm; P \ 0.01). The HFln response was reduced in the SCI (0.01 +/- 1.59) as compared with the young controls (1.50 +/- 1.50; P \ 0.05), but was not different from the old controls (0.69 +/- 1.39). The bradycardia did not differ among the young and old controls; however, the vagal response was attenuated in the old compared with the young. These data suggest that age does not significantly alter the heart rate response to the CFT, but attenuates the vagal response. CONCLUSION: In the SCI group, the paradoxical heart rate response to facial cooling and the lack of vagal activation suggest that abnormal autonomic cardiovascular reflexive control may result from profound inactivity and/or from the spinal cord injury per se.