Lisa M. K. Chin

Benefits of intensive treadmill exercise training on cardiorespiratory function and quality of life in patients with pulmonary hypertension.

BACKGROUND Pulmonary hypertension (PH) restricts the ability to engage in physical activity and decreases longevity. We examined the impact of aerobic exercise training on function and quality of life in patients with World Health Organization group 1 PH. METHODS Patients were randomized to a 10-week education only (EDU) or education/exercise combined (EXE) group. The exercise program consisted of 24-30 sessions of treadmill walking for 30-45 min per session at 70% to 80% of heart rate reserve. Outcome variables included changes in 6-min walk test (6MWT) distance, time to exercise intolerance, peak work rate (WR) from a cardiopulmonary treadmill test, and quality-of-life measures, including the Short Form Health Survey, version 2 (SF-36v2) and Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR). RESULTS Data are presented as mean SD. Twenty-three women (age, 54 11 years; BMI, 31 7 kg/m 2 ) were randomized to the EDU (n 5 13) or EXE (n 5 10) groups. Following 10 weeks of intervention, patients in the EXE group demonstrated an improvement in 6MWT distance (56 45 m; P 5 .002), increased time to exercise intolerance (1.9 1.3 min; P 5 .001), and peak WR (26 23 W; P 5 .004). Additionally, the EXE group scored significantly ( P , .050) better on six of the eight scales on SF-36v2, and fi ve of the six scales on CAMPHOR. In contrast, no significant improvement was observed for any of the outcome measures following EDU. No adverse events were noted in either group. CONCLUSION Ten weeks of brisk treadmill walking improved 6MWT distance, cardiorespiratory function, and patient-reported quality of life in female patients with group 1 PH.

Hyperventilation‐induced hypocapnic alkalosis slows the adaptation of pulmonary O2 uptake during the transition to moderate‐intensity exercise

The effect of voluntary hyperventilation‐induced hypocapnic alkalosis (RALK) on pulmonary O2 uptake () kinetics and muscle deoxygenation was examined in young male adults (n= 8) during moderate‐intensity exercise. Subjects performed five repetitions of a step‐transition in work rate from 20 W cycling to a work rate corresponding to 90% of the estimated lactate threshold during control (CON; , ∼40 mmHg) and during hyperventilation (RALK; , ∼20 mmHg). was measured breath‐by‐breath and relative concentration changes in muscle deoxy‐ (ΔHHb), oxy‐ (ΔO2Hb) and total (ΔHbtot) haemoglobin were measured continuously using near‐infrared (NIR) spectroscopy (Hamamatsu, NIRO 300). The time constant for the fundamental, phase 2, response (τ) was greater (P < 0.05) in RALK (48 ± 11 s) than CON (31 ± 9 s), while τHHb was similar between conditions (RALK, 12 ± 4 s; CON, 11 ± 4 s). The ΔHbtot was lower (P < 0.05) in RALK than CON, prior to (RALK, −3 ± 5 μmol l−1; CON, −1 ± 4 μmol l−1) and at the end (RALK, 1 ± 6 μmol l−1; CON, 5 ± 5 μmol l−1) of moderate‐intensity exercise. Although slower adaptation of during RALK may be related to an attenuated activation of PDH (and other enzymes) and provision of oxidizable substrate to the mitochondria (i.e. metabolic inertia), the present findings also suggest a role for a reduction in local muscle perfusion and O2 delivery.

Improved Cognitive Performance Following Aerobic Exercise Training in People With Traumatic Brain Injury

OBJECTIVE To examine cognitive function in individuals with traumatic brain injury (TBI) prior to and after participation in an aerobic exercise training program. DESIGN Pre-post intervention study. SETTING Medical research center. PARTICIPANTS Volunteer sample of individuals (N=7) (age, 33.3±7.9y) with chronic nonpenetrating TBI (injury severity: 3=mild, 4=moderate; time since most current injury: 4.0±5.5y) who were ambulatory. INTERVENTION Twelve weeks of supervised vigorous aerobic exercise training performed 3 times a week for 30 minutes on a treadmill. MAIN OUTCOME MEASURES Cognitive function was assessed using the Trail Making Test Part A (TMT-A), Trail Making Test Part B (TMT-B), and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Sleep quality and depression were measured with the Pittsburgh Sleep Quality Index (PSQI) and Beck Depression Inventory, version 2 (BDI-II). Indices of cardiorespiratory fitness were used to examine the relation between improvements in cognitive function and cardiorespiratory fitness. RESULTS After training, improvements in cognitive function were observed with greater scores on the TMT-A (10.3±6.8; P=.007), TMT-B (9.6±7.0; P=.011), and RBANS total scale (13.3±9.3; P=.009). No changes were observed in measures of the PSQI and BDI-II. The magnitude of cognitive improvements was also strongly related to the gains in cardiorespiratory fitness. CONCLUSIONS These findings suggest that vigorous aerobic exercise training may improve specific aspects of cognitive function in individuals with TBI and cardiorespiratory fitness gains may be a determinant of these improvements.

Improved cardiorespiratory fitness with aerobic exercise training in individuals with traumatic brain injury

Objective:To examine cardiorespiratory fitness in individuals with traumatic brain injury (TBI), before and following participation in a supervised 12-week aerobic exercise training program. Methods:Ten subjects with nonpenetrating TBI (TBI severity: mild, 50%; moderate, 40%; severe, 10%; time since injury [mean ± SD]: 6.6 ± 6.8 years) performed exercise training on a treadmill 3 times a week for 30 minutes at vigorous intensity (70%-80% of heart rate reserve). All subjects completed a cardiopulmonary exercise test, with pulmonary gas exchange measured and a questionnaire related to fatigue (Fatigue Severity Scale) at baseline and following exercise training. Results:After training, increases (P < .01) in peak oxygen consumption (; +3.1 ± 2.4 mL/min/kg), time to volitional fatigue (+1.4 ± 0.8 minutes), and peak work rate (+59 ± 43 W) were observed. At the anaerobic threshold, (+3.6 ± 2.1 mL/kg/min), treadmill time (+1.8 ± 1.1 minutes), and work rate (+37 ± 39 W) were higher (P < .01) following exercise training. Subjects also reported significantly lower (P < .05) Fatigue Severity Scale composite scores (−0.9 ± 1.3) following exercise training. Conclusion:These findings suggest that individuals with TBI may benefit from participation in vigorous aerobic exercise training with improved cardiorespiratory fitness and diminished fatigue.

Cardiorespiratory function before and after aerobic exercise training in patients with interstitial lung disease.

PURPOSE: To characterize the cardiorespiratory response to exercise before and after aerobic exercise training in patients with interstitial lung disease. METHODS: We performed a clinical study, examining 13 patients (New York Heart Association/World Health Organization Functional class II or III) before and after 10 weeks of supervised treadmill exercise walking, at 70% to 80% of heart rate reserve, 30 to 45 minutes per session, 3 times a week. Outcome variables included measures of cardiorespiratory function during a treadmill cardiopulmonary exercise test, with additional near infrared spectroscopy measurements of peripheral oxygen extraction and bioimpedance cardiography measurements of cardiac output. Six-minute walk test distance was also measured. RESULTS: All subjects participated in at least 24 of their 30 scheduled exercise sessions with no significant adverse events. After training, the mean 6-minute walk test distance increased by 52 ± 48 m (P = .001), peak treadmill cardiopulmonary exercise test time increased by 163 ± 130 s (P = .001), and time to achieve gas exchange threshold increased by 145 ± 37 s (P < .001). Despite a negligible increase in peak o2 with no changes to cardiac output, the overall work rate/ o2 relationship was enhanced after training. Muscle O2 extraction increased by 16% (P = .049) after training. CONCLUSIONS: Clinically significant improvements in cardiorespiratory function were observed after aerobic exercise training in this group of subjects with interstitial lung disease. These improvements appear to have been mediated by increases in the peripheral extraction of O2 rather than changes in O2 delivery.

Effect of Aerobic Exercise Training on Mood in People With Traumatic Brain Injury: A Pilot Study

Background: Exercise training is associated with elevations in mood in patients with various chronic illnesses and disabilities. However, little is known regarding the effect of exercise training on short and long-term mood changes in those with traumatic brain injury (TBI). Objective: The purpose of this study was to examine the time course of mood alterations in response to a vigorous, 12-week aerobic exercise training regimen in ambulatory individuals with chronic TBI (>6 months postinjury). Methods: Short and long-term mood changes were measured using the Profile of Mood States-Short Form, before and after specific aerobic exercise bouts performed during the 12-week training regimen. Results: Ten subjects with nonpenetrating TBI (6.6 ± 6.8 years after injury) completed the training regimen. A significant improvement in overall mood was observed following 12 weeks of aerobic exercise training (P = .04), with moderate to large effect sizes observed for short-term mood improvements following individual bouts of exercise. Conclusions: Specific improvements in long-term mood state and short-term mood responses following individual exercise sessions were observed in these individuals with TBI. The largest improvement in overall mood was observed at 12 weeks of exercise training, with improvements emerging as early as 4 weeks into the training regimen.

Effect of voluntary hyperventilation with supplemental CO2 on pulmonary O2 uptake and leg blood flow kinetics during moderate‐intensity exercise

•  What is the central question of this study? Voluntary hyperventilation that induces hypocapnic alkalosis (HYPO) is associated with slowed adaptation of O2 uptake and leg blood flow during moderate exercise; however, it is unknown whether hypocapnia, alkalosis and/or the hyperventilation manoeuvre is related to these observations. •  What is the main finding and its importance? We included a condition with the same work of breathing as HYPO, but the fall in CO2 was prevented by the addition of higher CO2 to the inspirate (normocapnia). This condition demonstrated that hypocapnia/alkalosis was responsible for the slower leg blood flow response; however, the act of hyperventilation itself also had a role to play in the slower O2 uptake kinetics.

Oxygen uptake on-kinetics before and after aerobic exercise training in individuals with traumatic brain injury

Abstract Objective: The high prevalence of fatigue among persons with traumatic brain injury (TBI) may be related to poor cardiorespiratory fitness observed in this population. Oxygen uptake on-kinetics is a method of assessing cardiorespiratory fitness and may be used to examine performance fatigability (decline in performance during a given activity) in persons with TBI. Purpose: To examine the effect of aerobic exercise training on oxygen uptake on-kinetics during treadmill walking in individuals with TBI. Methods: Seven ambulatory adults with chronic non-penetrating TBI performed short moderate-intensity (3–6 metabolic equivalents) walking bouts on a treadmill, prior to and following an aerobic exercise training program (clinicaltrials.gov: NCT01294332). The 12-week training program consisted of vigorous-intensity exercise on a treadmill for 30 min, 3 times a week. Breath-by-breath pulmonary gas exchange was measured throughout the bouts, and oxygen uptake on-kinetics described the time taken to achieve a steady-state response. Results: Faster oxygen uptake on-kinetics was observed after exercise training, for both the absolute and relative intensity as pre-training. Conclusions: Faster oxygen uptake on-kinetics following aerobic exercise training suggests an attenuated decline in physical performance during a standardized walking bout and improved performance fatigability in these individuals with TBI. Implications for rehabilitation Severe fatigue is a common complaint among persons with traumatic brain injury (TBI). Oxygen uptake on-kinetics may be used as an objective physiological measure of performance fatigability in persons with TBI. Faster oxygen uptake on-kinetics following aerobic exercise training suggests improved performance fatigability in these individuals with TBI. Aerobic exercise training appeared beneficial for reducing performance fatigability and may be considered as part of the rehabilitative strategy for those living with TBI.