Arm Cycling Exercise Research Articles

Role of the sympathoadrenergic system in adipose tissue metabolism during exercise in humans.

1. The relative roles of sympathetic nerve activity and circulating catecholamines for adipose tissue lipolysis during exercise are not known. 2. Seven paraplegic spinal cord injured (SCI, injury level T3-T5) and seven healthy control subjects were studied by microdialysis and (133)xenon washout in clavicular (Cl) and in umbilical (Um) (sympathetically decentralized in SCI) subcutaneous adipose tissue during 1 h of arm cycling exercise at approximately 60 % of the peak rate of oxygen uptake. 3. During exercise, adipose tissue blood flow (ATBF) and interstitial glycerol, lactate and noradrenaline concentrations increased significantly in both groups. Plasma catecholamine levels increased significantly less with exercise in SCI than in healthy subjects. The exercise-induced increase in interstitial glycerol concentration in subcutaneous adipose tissue was significantly lower in SCI compared with healthy subjects (SCI: 25 +/- 12 % (Cl), 36 +/- 20 % (Um); healthy: 60 +/- 17 % (Cl), 147 +/- 45 % (Um)) and the increase in ATBF was significantly lower (Cl) or similar (Um) in SCI compared with healthy subjects (SCI: 1.2 +/- 0.3 ml (100 g)(-1) min(-1) (Cl), 1.0 +/- 0.3 ml (100 g)(-1) min(-1) (Um); healthy: 2.8 +/- 0.7 ml (100 g)(-1) min(-1) (Cl), 0.6 +/- 0.3 ml (100 g)(-1) min(-1) (Um)). Accordingly, in both adipose tissues lipolysis increased less in SCI compared with healthy subjects, indicating that circulating catecholamines are important for the exercise-induced increase in subcutaneous adipose tissue lipolysis. In SCI subjects, the exercise-induced increase in subcutaneous adipose tissue lipolysis was not lower in decentralized than in sympathetically innervated adipose tissue. During exercise the interstitial noradrenaline and adrenaline concentrations were lower in SCI compared with healthy subjects (P < 0.05) and always lower than arterial plasma catecholamine concentrations (P < 0.05). 4. It is concluded that circulating catecholamines are important for the exercise-induced increase in subcutaneous adipose tissue lipolysis while sympathetic nerve activity is not.

Peak and kinetic cardiorespiratory responses during arm and leg exercise in patients with spinal cord injury.

A paired comparison of the peak and submaximal responses of oxygen uptake and heart rate in patients with spinal cord injury (SCI) performing voluntary arm cycle exercise and functional electrical stimulation (FES) leg cycling exercise. To test if the blunted heart rate response and slower rate of adjustment of oxygen uptake seen in patients with SCI performing FES leg cycle exercise are also characteristic of arm exercise in these patients. Eight paraplegics performed incremental and constant work rate (CWR) exercise with the legs and arms. Mean response times (MRT) for Vo2 during exercise (on) and in recovery (off) were calculated from the breath-by-breath Vo2 profile. Peak heart rate was higher during incremental arm exercise, and uncorrelated with that observed during incremental FES leg cycling. For the same increase in Vo2, constant work rate arm exercise was associated with faster (and normal) Vo2 kinetics, greater increase in heart rate, and lower end-exercise blood lactate, compared to FES leg cycling. The consistently higher peak heart rate and Vo2, and faster Vo2 kinetics, for voluntary arm compared to FES leg cycle exercise suggest no intrinsic dysfunction of heart rate control in these paraplegics. Rather, these data suggest that during FES leg cycling the changes seen are due to some characteristic specific to the injury, such as reduced muscle mass and/or deconditioning of the remaining muscle. This research was supported by The Department of Veterans Affairs, Rehabilitation Research and Development Project #B603-RA. Spinal Cord (2000) 38, 340 - 345.

Respiratory response to exercise in postpolio patients with severe inspiratory muscle dysfunction

Objectives: To evaluate the limiting factors of exercise performance and to analyze the respiratory strategies adopted during exercise in postpolio patients with severe inspiratory muscle dysfunction. Patients: Five patients with prior poliomyelitis associated with scoliosis and with respiratory muscle dysfunction (mean vital capacity, 1.74L [range, 1.1 to 2.4]) were studied at rest and during leg or arm cycle exercise. Methods: Gas exchange was examined by arterial blood gases and mass spectrometry of expired air. Ventilatory mechanics were studied by measurement of esophageal and gastric pressures. Results: Blood gases at rest were normal, except for subnormal Po 2 levels in three patients. In all but one patient, ventilatory insufficiency was the limiting factor for exercise. A compensatory breathing pattern with abdominal muscle recruitment during expiration was present already at rest in three of the patients. The pressures generated by the diaphragm were below fatiguing margins, ie, levels that in healthy subjects can be sustained for at least 45 minutes. Conclusions: The extent of ventilatory dysfunction was not evident in blood gas values at rest; however, it was revealed by blood gas values during the exercise test. Diaphragm fatigue seems to be avoided at the cost of impaired blood gases.

Metabolic efficiency during arm and leg exercise at the same relative intensities

This study was conducted to compare gross efficiency (GE), net efficiency (NE), work efficiency (WE), and delta efficiency (DE) between arm crank and cycle exercise at the same relative intensities. Eight college-aged males underwent two experimental trials presented in a randomized counterbalanced order. During each trial subjects performed three intermittent 7-min exercise bouts separated by 10-min rest intervals on an arm or semirecumbent leg ergometer. The power outputs for the three bouts of arm crank or cycle exercise corresponded to 50, 60, and 70% of the mode-specific VO2peak. GE, NE, and WE were determined as the ratio of Kcal.min-1 equivalent of power output to Kcal.min-1 of total energy expended, energy expended above rest and energy expended above unloaded exercise, respectively. DE was determined as the ratio of the increment of Kcal.min-1 of power output above the previous lower intensity to the increment of kcal.min-1 of total energy expended above the previous lower intensity. GE and NE did not differ between arm crank and cycle exercises. However, WE was lower (P < 0.05) during arm crank than cycle exercise at 50, 60, and 70% VO2peak. DE was also lower (P < 0.05) during arm crank than cycle exercise at delta 50-60 and at delta 60-70% VO2peak. It is concluded metabolic efficiency as determined by work and delta efficiency indices was lower during arm crank compared with cycle exercise at the same relative intensities. These findings add to the understanding of the difference in metabolic efficiency between upper and lower body exercise.

O2 uptake kinetics and the O2 deficit as related to exercise intensity and blood lactate

The dynamic responses of O2 uptake (VO2) to a range of constant power output levels were related to exercise intensity [as percent maximal VO2 and as below vs. above lactic acid threshold (LAT)] and to the associated end-exercise lactate in three groups of subjects: group I, untrained subjects performing leg cycle ergometer exercise; group II, the same subjects performing arm cycle exercise; and group III, trained cyclists performing leg cycle ergometer exercise. Responses were described by a double-exponential equation, with each component having an independent time delay, which reduced to a monoexponential description for moderate (below-LAT) exercise. When a second exponential component to the VO2 response was present, it did not become evident until approximately 80-100 s into exercise. An overall time constant (tau T, determined as O2 deficit for the total response divided by net end-exercise VO2) and a primary time constant (tau P, determined from the O2 deficit and the amplitude for the early primary VO2 response) were compared. The tau T rose with power output and end-exercise lactate levels, but tau P was virtually invariant, even at high end-exercise lactate levels. Moreover the gain of the primary exponential component (as delta VO2/delta W) was constant across power outputs and blood lactate levels, suggesting that the primary VO2 response reflects a linear system, even at higher power outputs. These results suggest that elevated end-exercise lactate is not associated with any discernible slowing of the primary rise in VO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of Arm Crank Exercise in the Detection of Abnormal Pulmonary Gas Exchange in Patients at Low Altitude

The measurement of arterial blood gases, P(A-a)O2 and VD/VT, during cycle ergometry is the "gold standard" for the assessment of pulmonary gas exchange. However, some patients are unable to perform cycle ergometry because of other medical problems. To determine whether arm crank exercise could be used to reliably detect gas exchange abnormalities compared to cycle ergometry. Fifteen patients with a variety of pulmonary disorders, who were referred for exertional dyspnea. All patients performed maximal arm crank and cycle exercise. Arterial blood gases, VO2, VCO2, and VE were measured at rest and during exercise. Compared to peak cycle exercise (mean +/- SD), PaO2 (85 +/- 14 vs 75 +/- 13 mm Hg), SaO2 (94 +/- 2 vs 91 +/- 4 percent), VD/VT (0.21 +/- 0.07 vs 0.19 +/- 0.08), and pH (7.37 +/- 0.04 vs 7.34 +/- 0.03) were significantly higher during peak arm crank exercise. The P(A-a)O2 (18 +/- 13 vs 29 +/- 12 mm Hg) was narrower, and PaCO2 (29 +/- 3 vs 29 +/- 4 mm Hg) and PAO2 (104 +/- 4 vs 103 +/- 4 mm Hg) were similar. Six patients had normal gas exchange during cycle exercise at low altitude (P[A-a]O2 less than or equal to 27 mm Hg, PaO2 greater than or equal to 65 mm Hg, VD/VT less than or equal to 0.18) and nine were abnormal. Utilizing criteria specific for arm crank at low altitude, the same six patients had normal gas exchange (P[A-a]O2 less than or equal to 13 mm Hg, PaO2 greater than or equal to 85 mm Hg, VD/VT less than or equal to 0.26), and the remaining nine were abnormal. The P(A-a)O2 during peak arm crank was the most useful criterion in identifying patients with abnormal gas exchange. Proposed criteria for arm crank exercise testing accurately identified all patients with normal and abnormal pulmonary gas exchange during cycle exercise. The data from the present study suggest that arm crank can be an acceptable alternative exercise testing modality for the assessment of pulmonary gas exchange.

Gas Exchange During Maximal Upper Extremity Exercise

to characterize gas exchange and cardiopulmonary performance during maximal progressive arm crank exercise. Cardiopulmonary variables were measured and arterial blood gases were determined in blood samples obtained from an indwelling radial arterial catheter during arm crank exercise (34 watts/min). Arm crank exercise was compared to maximal leg exercise performed by a different but comparable group of subjects from a previous study. 19 healthy young (mean +/- SEM: 20 +/- 1 yr) black males. Peak arm crank exercise resulted in lower values compared to peak leg exercise for: power (129 +/- 2 vs 253 +/- 10 W), VO2 (2.17 +/- 0.04 vs 3.26 +/- 0.14 L/min); VCO2 (2.9 +/- 0.11 vs 4.32 +/- 0.17 L/min); HR (168 +/- 3 vs 189 +/- 3 beats/min); AT (1.15 +/- 0.05 vs 1.83 +/- 0.07 L/min); and VE (101 +/- 2 vs 144 +/- 8 L/min), respectively. Arm crank exercise (baseline vs peak) elicited an impressive improvement in PaO2 (85 +/- 1 to 97 +/- 1 mm Hg), no change in SaO2 (96 +/- 0.2 to 96 +/- 0.2 percent), no significant increase in P(A-a)O2 (3 +/- 0.7 to 5 +/- 0.9 mm Hg) and an appropriate trending decrease in VD/VT (0.22 +/- 0.01 to 0.17 +/- 0.01). Peak arm crank values were significantly different from peak cycle exercise for PaO2 (82 +/- 2.2 mm Hg), SaO2 (93 +/- 0.4 percent), P(A-a)O2 (21 +/- 1.9 mm Hg) and VD/VT (0.08 +/- 0.01). At comparable levels of VO2 for arm crank and cycle exercise (2.17 +/- 0.04 vs 2.26 +/- 0.08 L/min), significant differences were observed for PaO2 (97 +/- 1.4 vs 81 +/- 1.9 mm Hg); SaO2 (96 +/- 0.2 vs 94 +/- 0.4 percent); P(A-a)O2 (5 +/- 0.9 vs 14 +/- 1.5 mm Hg); and VD/VT (0.17 +/- 0.01 vs 0.08 +/- 0.01), respectively. Maximal arm crank exercise represents a submaximal cardiopulmonary stress compared to maximal leg exercise. The differences in gas exchange observed at peak exercise between arm crank and leg exercise for the most part reflect the lower VO2 achieved. However, the persistence of these gas exchange differences even at a comparable level of VO2 suggests that factors other than VO2 may be operative. These factors may include differences in alveolar ventilation, CO2 production, ventilation-perfusion inequality, diffusion, and control of breathing.

Differences in cardiorespiratory responses during and after arm crank and cycle exercise

The differences in cardiorespiratory responses were examined during and after intermittent progressive maximal arm-crank and cycle exercise. Arm-crank exercise was performed in a standing position using no torso restraints to maximize the amount of active skeletal muscle mass. Recovery was followed for 16 min. In the tests a variety of ventilatory gas exchange variables, heart rate, the blood pressure, and the arm venous blood lactate concentration were measured in 21 untrained healthy men aged 24-45 years. At equal submaximal external workloads for arm cranking and cycling (50 and 100 W) the respiratory frequency, tidal volume, pulmonary ventilation, oxygen uptake, carbon dioxide output, the respiratory exchange ratio, heart rate, the arm venous blood lactate concentration, and the ventilatory equivalent for oxygen were higher (P less than 0.001) during arm cranking than cycling. The maximal workload for arm cranking was 44% lower than that for cycling (155 +/- 37 vs 277 +/- 39 W, P less than 0.001) associated with significantly (P less than 0.001) lower maximal tidal volume (-20%), oxygen uptake (-22%), carbon dioxide output (-28%), systolic blood pressure (-17%) and oxygen pulse (-22%) but a higher ventilatory equivalent for carbon dioxide (+22%) and arm venous blood lactate concentration (+37%). However, these responses after arm-crank and cycle exercises behaved almost similarly during recovery. The high cardiorespiratory stress induced by arm work should be taken into account when the work stress and work-rest regimens in actual manual tasks are assessed, and when arm work is used for clinical testing, and in physiotherapy particularly for patients with heart or pulmonary diseases.

Physiological responses during and after intermittent sorting of postal parcels

Physiological responses including ventilatory gas exchange, blood lactate (LA) and heart rate (HR) were studied during and after intermittent manual sorting of postal parcels in a simulated workplace constructed in the laboratory. Responses to parcel sorting were compared to those obtained during arm crank and cycle exercise. The subjects were 21 healthy male sorters. Their age was 33 ±6 years and weight 78·3 ±12·7 kg. The subjects' maximal oxygen consumption ([Vdot]O2 max) was 2·52±0·32 Imin−1 for arm cranking, and 3·24+0·441min−1 for cycling. The subjects sorted parcels with a mean weight of 51 kg from a container onto two trollies for 3·5 min at each of the following work rates; slow (3 ± 0 parcels min−1), habitual (8·6±2·4 parcels min−1), accelerated (10·8 ± 3middot;1 parcels min−1), and maximal (16·9 ±7·6 parcels min−1). The tasks were separated by rest periods of 30 s for venous blood sampling, and the recovery was followed for 16 min. At the habitual work rate, [Vdot]O2 was 1·36±0·381min−1, LA 1·8±0·9mmol−1, and HR 105 ± 22 beats min−1. The parcel sorting studied was predominantly aerobic (LA<4·0mmol l−1) up to the work rate of about 20parcelsmin−1. After the recovery period, breathing frequency and HR remained significantly higher than at rest. The physiological responses to parcel sorting substantially differed from those to arm cranking, whereas they were almost equal to cycling.

Thermoregulatory responses to upper body exercise.

The purpose of this study was to compare thermoregulatory responses between upper body and lower body exercise. Nine male subjects performed 60 min of arm crank (AC) and cycle (CY) exercise at the same absolute intensity (oxygen uptake = 1.61 X min-1) and at the same relative intensity (60% of ergometer specific peak oxygen uptake) in a temperate (24 degrees C, 20% rh) environment. During the absolute intensity experiments, rectal temperature and sweating rate responses were essentially the same for both modes of exercise. In addition, no differences were found for chest, back, arm, or thigh skin temperatures, but calf skin temperature was significantly (P less than 0.05) lower during arm crank than cycle exercise. During the relative intensity experiments, thermoregulatory responses were lower during arm crank than cycle exercise. In addition, we found no difference between esophageal and rectal temperature values elicited by arm crank exercise. These results indicate that the examined thermoregulatory responses are independent of the skeletal muscle mass employed and dependent upon the absolute metabolic intensity.