Kunio Kikuchi

Cardiovascular and respiratory responses to passive leg cycle exercise in people with spinal cord injuries

The purpose of this study was to determine the effect of passive leg cycle exercise (PLE) on cardiovascular and respiratory responses in people with spinal cord injuries (PSCI). Eight PSCI with lesions from T8 to L1 and five control subjects (CS) performed PLE at pedalling frequencies of 20 or 40 rpm for 7 min at room temperature of about 25°C. We measured, at rest and during PLE, the pulmonary ventilation (VE), oxygen uptake (VO2), cardiac output (Q), stroke volume (SV), heart rate (HR) and arterial blood pressure, as well as the skin blood flow (SBF) in the lower limb after PLE. An increase in pedalling frequency promoted an increase in VE and VO2 in both groups. Compared with the CS, the PSCI showed significantly smaller increases in VO2 (P < 0.05). The Qc was significantly elevated during PLE at 20 and 40 rpm in CS, and at 40 rpm in PSCI (P < 0.05). In CS, it resulted from increases in both SV and HR, whereas in PSCI, it was contributed to by a greater increase in SV without a rise in HR. In CS, the increase in pedalling frequency promoted the increases in SV and HR and consequently in Qc In PSCI, however, the values remained constant irrespective of pedalling frequency. The arterial blood pressure and SBF in the lower limbs were unchanged by PLE in both groups. These results would suggest that passive leg exercise promotes venous return from the paralyzed lower limbs in PSCI.

Effect of arm cranking exercise on skin blood flow of lower limb in people with injuries to the spinal cord

The purpose of this study was to examine whether arm cranking exercise induces changes in skin blood flow in the paralyzed lower limbs of people with injuries to the spinal cord (PISC). Ten PISC with lesions located between Th5 and L5 and six control subjects performed arm cranking exercise for 6 min at three intensities, 10, 30 and 50 W, at a room temperature of 25°C. Oxygen uptake (Vo2) and heart rate (HR) were measured for the last 2 min of each exercise period. The skin blood flow at the anterior thigh (BFsk,t) was continuously monitored using laser Doppler flowmetry for the whole 6-min period and for the first 10 min of recovery following exercise. During exercise, the PISC showed lower Vo2 and greater HR than the control subjects. No increase in BFsk,t was found in six of the PISC with lesions at or above Th12, irrespective of the exercise intensity. On the other hand, in PISC with lesions at L1 or below, BFsk,t increased significantly (P < 0.05) with an increase in Vo2 and HR, although the BFsk,t at a given Vo2 and HR was lower than that in the control subjects. These results would suggest that arm exercise can promote the blood circulation in the skin of the lower limbs if the injury level is below L1.

Relationship between core temperature and skin blood flux in lower limbs during prolonged arm exercise in persons with spinal cord injury.

The purposes of the present study were to examine the response of the skin blood flux (SBF) in the paralyzed lower limbs of persons with spinal cord injury (PSCI) and to clarify the relationship between the SBF and core temperature during prolonged arm exercise. Eight male PSCI with lesions from T6 to L5 and six male control subjects (CS) participated in this study. The subjects rested for 60 min and then performed arm-cranking exercise at 20 W for 30 min at 25 °C. The tympanic membrane temperature (Tty) and SBF in the anterior thigh (SBFT) and in the posterior calf (SBFC) were continuously measured throughout the experiment. The SBFC did not change in either PSCI or CS during the experiment. The SBFT in four PSCI with high lesions (T6 to T12), remained unchanged during exercise. The SBFT in the other four PSCI with low lesions (T12 to L5, ΔSBFT+) began to elevate markedly when the T t, exceeded a threshold temperature of 36.69 °C. The pattern of increase of SBFT in ΔSBFT+ was similar to that in CS, although onset of the increase in SBFT was delayed and the peak of SBFT during exercise was significantly lower in comparison with the CS. We consider that these differences between the ΔSBFT+ and CS were largely attributable to the lowerTty in the former group, which took a prolonged time to reach the threshold of 36.69 °C.

Effect of maximal arm exercise on skin blood flux in the paralyzed lower limbs in persons with spinal cord injury

The purpose of the present study was to examine the effect of maximal arm exercise on the skin blood circulation of the paralyzed lower limbs in persons with spinal cord injury (PSCI). Eight male PSCI with complete lesions located between T3 and L1 performed graded maximal arm-cranking exercise (MACE) to exhaustion. The skin blood flux at the thigh (SBFT) and that at the calf (SBFC) were monitored using laser-Doppler flowmeter at rest and for 15 s immediately after the MACE. The subjects mean peak oxygen uptake and peak heart rate was 1.41 ± 0.22 1·min−1 and 171.6 ± 19.2 beats·min−1, respectively. No PSCI showed any increase in either SBFT or SBFC after the MACE, when compared with the values at rest. These results suggest that the blood circulation of the skin in the paralyzed lower limbs in PSCI is unaffected by the MACE.

Exercise-Induced Temperature Changes in the Tympanic Membrane and Skin of Patients with Spinal Cord Injury

The kinetics of thermoregulation mechanisms were observed in patients with spinal cord injury (SCI) during exercise. Five patients with paraplegia (T4–T12/L1) due to spinal cord injury underwent arm cranking exercise after 60min of rest in the sitting position. The exercises were conducted with incremental increases (5 watts/min) in external workload starting at 0 watts (50rpm). They were performed in a climato-therapeutic chamber at 25°C and a relative humidity between 50%–60%. The patients were worked to exhaustion. Tympanic membrane (Tty) and the skin (Tsk; head, arms, chest, thigh, and shin) temperatures were measured at rest and during exercise. Results of the measurements showed that Tty in the SCI group was lower both at rest (36.15°–36.65°C) and during exercise (36.15°–36.70°C) than in the healthy control group. Tsk were also lower at all measured sites. The differences in the temperatures were especially marked at sites where dermal sensation was impaired such as the thighs and shins. It is concluded that the lower temperatures were due to disturbances in the input of thermal information to the thermoregulatory nucleus as well as the generation and modification of output command signals and responses with regard to the regulation of temperature which were caused by the spinal cord injury.