Cardiovascular responses to dynamic and static upper-body exercise in a cold environment in coronary artery disease patients

Purpose Upper-body exercise performed in a cold environment may increase cardiovascular strain, which could be detrimental to patients with coronary artery disease (CAD). This study compared cardiovascular responses of CAD patients during graded upper-body dynamic and static exercise in cold and neutral environments. Methods 20 patients with stable CAD performed 30 min of progressive dynamic (light, moderate, and heavy rating of perceived exertion) and static (10, 15, 20, 25 and 30% of maximal voluntary contraction) upper body exercise in cold (− 15 °C) and neutral (+ 22 °C) environments. Heart rate (HR), blood pressure (BP) and electrocardiographic (ECG) responses were recorded and rate pressure product (RPP) calculated. Results Dynamic-graded upper-body exercise in the cold increased HR by 2.3–4.8% (p = 0.002–0.040), MAP by 3.9–5.9% (p = 0.038–0.454) and RPP by 18.1–24.4% (p = 0.002–0.020) when compared to the neutral environment. Static graded upper-body exercise in the cold resulted in higher MAP (6.3–9.1%; p = 0.000–0.014), lower HR (4.1–7.2%; p = 0.009–0.033), but unaltered RPP compared to a neutral environment. Heavy dynamic exercise resulted in ST depression that was not related to temperature. Otherwise, ECG was largely unaltered during exercise in either thermal condition. Conclusions Dynamic- and static-graded upper-body exercise in the cold involves higher cardiovascular strain compared with a neutral environment among patients with stable CAD. However, no marked changes in electric cardiac function were observed. The results support the use of upper-body exercise in the cold in patients with stable CAD. Trial registration Clinical trial registration NCT02855905 August 2016.

The effects of an upper body conditioning stimulus on lower body post-activation performance enhancement (PAPE): a pilot study

Complex training where a high-load conditioning stimulus (CS) is performed prior to a biomechanically similar plyometric movement has been demonstrated to acutely enhance the performance of the plyometric movement in a phenomenon called post-activation performance enhancement (PAPE). Despite the positive influence PAPE can have on power production, the abundance of research has only investigated PAPE locally while comparing biomechanically similar movements. The purpose of this study was to determine if a heavy barbell bench press could elicit PAPE in a lower body plyometric movement. Eight (n = 8) resistance-trained males performed one set of countermovement jumps (CMJs) before (pre-CS) and three sets of CMJs after (post-CS) a heavy bench press set. Changes in muscle activation, jump height, work, power output, and rate of force development (RFD) during the early (E-RFD) and late (L-RFD) stages were compared between pre-CS and post-CS. The level of significance was set at p < .05. There were no significant differences in muscle activation, jump height, work, power output, or E-RFD (p > .05). There was a significant increase in L-RFD between pre-CS and the final set of jumps post-CS (p = .01). These results suggest that an upper body CS may not influence PAPE in the lower body. However, pairing a high-load upper body exercise with a lower body plyometric does not seem disadvantageous, and could be implemented as a strategy to maximize workout time efficiency with proper fatigue management incorporation.

Exercise-Related Effects on Executive Functions During a Simulated Underwater Extravehicular Activity

Objective Investigation of cognitive performance during extravehicular activities (EVAs) in a space-analog setting. Background EVAs performed by humans in microgravity on the International Space Station (ISS) call for high cognitive performance during upper-body workload. Higher cardiovascular demands interact with cognitive performance, but no knowledge exists about EVA’s special requirements. This study simulates EVA-training underwater to investigate its effects on the executive functions inhibition and switching. Method In a counterbalanced crossover design, 16 divers (age: 28 ± 2.4 years; eight females) performed two conditions (i.e., EVA vs. Inactivity [INACT]) in 3–5 m submersion (diving gear; not in a space-suit). EVA included 30 min of moderate-, followed by 30 min of high-intensity upper-body exercise intervals, paired with EVA-specific cognitive-motor tasks. INACT included no exercise in submersion and neutral buoyancy. Both conditions included cognitive testing at pre, mid (after the first 30 min), and post (after the second 30 min) on a tablet computer. Reaction times (RTs) and response accuracy (ACC) were calculated for both tasks. Results ACC was significantly lower during EVA compared with INACT for inhibition (post: p = .009) and switching (mid: p = .019) at post ( p = .005). RTs for inhibition were significantly faster during EVA ( p = .022; ηp 2 = 0.320). Conclusion Specific physical exercise, intensity, duration, and tasks performed during the EVA might differently affect the exercise-cognition interaction and need further investigation, especially for future long-term space travel. Application Future research might serve to improve mission success and safety for EVAs and long-term space travel.

Comparison of two Borg exertion scales for monitoring exercise intensity in able-bodied participants, and those with paraplegia and tetraplegia

Study design Cross-sectional cohort study. Objectives To compare ratings of perceived exertion (RPE) on Borg’s 6–20 RPE scale and Category Ratio 10 (CR10) in able-bodied (AB) participants during upper and lower body exercise, and recreationally active participants with paraplegia (PARA) and athletes with tetraplegia (TETRA) during upper body exercise only. Setting University and rehabilitation centre-based laboratories in UK and Netherlands. Methods Twenty-four participants were equally split between AB, PARA, and TETRA. AB performed maximal tests using cycle (AB-CYC) and handcycle (AB-HC) ergometry. PARA and TETRA performed maximal handcycle and wheelchair propulsion tests, respectively. Oxygen uptake (V̇O2) and blood lactate concentration were monitored throughout. RPE was rated each stage on Borg’s RPE scale and CR10. Thresholds were identified according to log-V̇O2 plotted against log-blood lactate (LT1), and 1.5 mmol L−1 greater than LT1 (LT2). Results RPE from both scales were best fit against each other using a quadratic model, with high goodness of fit between scales that was independent of exercise mode and participant group (range R2: 0.965–0.970, P < 0.005). Though percentage peak V̇O2 was significantly greater in TETRA (P < 0.005), there was no difference in RPE at LT1 or LT2 between groups on Borg’s RPE scale or CR10. Conclusion Strong association between Borg’s RPE scale and CR10 suggests they can be used interchangeably. RPE at lactate thresholds were independent of mode of exercise and level of spinal cord injury. However, inter-individual variation precludes from making firm recommendations about using RPE for prescribing homogenous exercise intensity.

Central aortic hemodynamics following acute lower and upper-body exercise in a cold environment among patients with coronary artery disease

Exercise is beneficial to cardiovascular health, evidenced by reduced post-exercise central aortic blood pressure (BP) and wave reflection. We assessed if post-exercise central hemodynamics are modified due to an altered thermal state related to exercise in the cold in patients with coronary artery disease (CAD). CAD patients (n = 11) performed moderate-intensity lower-body exercise (walking at 65–70% of HRmax) and rested in neutral (+ 22 °C) and cold (− 15 °C) conditions. In another protocol, CAD patients (n = 15) performed static (five 1.5 min work cycles, 10–30% of maximal voluntary contraction) and dynamic (three 5 min workloads, 56–80% of HRmax) upper-body exercise at the same temperatures. Both datasets consisted of four 30-min exposures administered in random order. Central aortic BP and augmentation index (AI) were noninvasively assessed via pulse wave analyses prior to and 25 min after these interventions. Lower-body dynamic exercise decreased post-exercise central systolic BP (6–10 mmHg, p < 0.001) and AI (1–6%, p < 0.001) both after cold and neutral and conditions. Dynamic upper-body exercise lowered central systolic BP (2–4 mmHg, p < 0.001) after exposure to both temperatures. In contrast, static upper-body exercise increased central systolic BP after exposure to cold (7 ± 6 mmHg, p < 0.001). Acute dynamic lower and upper-body exercise mainly lowers post-exercise central BP in CAD patients irrespective of the environmental temperature. In contrast, central systolic BP was elevated after static exercise in cold. CAD patients likely benefit from year-round dynamic exercise, but hemodynamic responses following static exercise in a cold environment should be examined further.Clinical trials.gov: NCT02855905 04/08/2016.

Recovery Off-Kinetics Following Exhaustive Upper Body Exercise in Spinal Cord Injury

Background: People with spinal cord injury (SCI) present with impaired autonomic control when the lesion is above T6. This could lead to delayed cardiorespiratory recovery following vigorous physical activity. Objectives: To characterize and compare gas exchange off-kinetics following exhaustive exercise in individuals with SCI and an apparently healthy control group. Methods: Participants were 19 individuals with SCI who presented with the inability to voluntarily lift their legs against gravity (age, 44.6 ± 14.2 years; AIS A, n = 5; AIS B, n = 7; AIS C, n = 7; paraplegia, n = 14; tetraplegia, n = 5) and 10 healthy comparisons (COM; age, 30.5 ± 5.3 years). All participants performed an arm ergometer cardiopulmonary exercise test (aCPET) to volitional exhaustion followed by a 10-minute passive recovery. O2 uptake (V̇o2) and CO2 output (V̇co2) off-kinetics was examined using a mono-exponential model in which tau off (τoff) and mean response time (MRT) were determined. The off-kinetics transition constant (Ktoff) was calculated as ΔV̇o2/MRT. Student t tests were used to compare SCI versus COM group means. Results: COM had a significantly higher relative peak V̇o2 compared to SCI (1.70 ± 0.55 L/min vs 1.19 ± 0.51 L/min, p = .019). No difference was observed for τoff between the groups, however Ktoff for both V̇o2 and V̇co2 was significantly lower in the SCI compared to the COM group. Conclusion: A reduced Ktoff during recovery may suggest inefficiencies in replenishing muscle ATP stores and lactate clearance in these participants with SCI. These findings may contribute to the observed lower cardiorespiratory fitness and greater fatigability typically reported in individuals with SCI.