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Contrast baths have been used for therapy for over 2,000 years. The basic concept is to alternate warm and cool water baths during a treatment session. It is believed that this will increase circulation better than just placing the limb in a warm water bath. However, there is little supportive evidence for this assertion. Further, for subjects with diabetes, with underlying impairments in their circulation, this may not work at all. Fourteen people with type 2 diabetes were compared to 14 age-matched controls. Skin blood flow of the foot (BF) was measured during 16 minutes of contrast baths at two different intervals: 3 minutes warm and 1 minute cold and 6 minutes warm and 2 minutes cold. In control subjects, warm and cold contrast baths with the ratio 3 minutes warm to 1 minute cold elicited significantly (p0.01) greater BF than placing the limb continuously in warm water or using a 6:2 ratio of warm to cold bath time. In control subjects, there was also a greater plantar than dorsal BF. For subjects with diabetes, there was no statistical difference between BF with contrast baths versus warm whirlpool; but in both cases BF was significantly less than that seen in control subjects under similar circumstances. There was also very little difference between BF on the plantar and dorsal aspects of the foot in the subjects with diabetes. Patients with diabetes do not show a vascular response to contrast bath therapy. The BF response to contrast temperatures may be a good diagnostic test for diabetic vascular impairment.

Limb blood flow and skin and deep tissue temperature change during the menstrual cycle. However, the impact of these changes on isometric exercise performance has not been investigated.Isometric endurance was assessed at contraction tensions of 20, 40 and 60% of the maximal voluntary contraction strength (MVC) of the handgrip muscles in 8 women every other day throughout their menstrual cycles (MC). For any MC, contractions were only accomplished at one of the three tensions. For contractions at 40% MVC, an additional two MC were studied during which the circulation to the forearm was occluded during the contractions in one cycle and muscle temperature stabilized and occluded in another cycle.The results of these experiments showed a small variation in endurance during the MC for contractions at 60% MVC. This effect increased at 40% and was greatest for contractions at 20% MVC. When circulation was occluded, the response was changed in both magnitude and timing during the MC showing that there was variation in muscle performance due to the menstrual cycle not due to changes in blood flow. Further, when muscle temperature was stabilized and flow occluded, there was still lower endurance at the end of the Follicular phase showing an effect of the menstrual cycle on endurance absent changes in muscle temperature and blood flow.The results show that the MC alters isometric endurance due to 1) a cyclic variation in muscle temperature, 2) direct effects of the menstrual cycle on circulation and 3) Direct effects of the MC on muscle.

Contrast baths (CB) have been used for over two thousand years. But it only was recently that CB were shown to improve limb circulation to a greater extent than that which can be seen after continuous exposure to a warm, constant temperature, bath. However, other studies show that this type of response to temperature can be impaired if the sympathetic nervous system applies vasoconstriction to the blood vessels. Therefore the purpose of the present investigation was to examine the relationship between sympathetic outflow on the magnitude of the change of blood flow (BF) during contrast baths in controls and with people diabetes. Sympathetic vasoconstriction activity was altered by global heating.Fourteen patients with type 2 diabetes were compared to 14 age-matched controls. BF was measured during 16 minutes of serial contrast baths of the foot following 3 minutes of warm water and 1 min of cold immersion at 2 different room temperatures, 19 and 32 deg C.When subjects were exposed to global heating (warm room) there is a greater response to CB than when subjects were initially in a cooler room. However, for both temperatures, subjects with diabetes had a response that was over 50% less than that seen in control subjects.Removing sympathetic vasoconstrictor tone by global heating benefits subjects with diabetes and control subjects in their response to CB. For subjects with diabetes, global heating may be necessary to increase blood flow to acceptable levels for effective therapy.

While it is well documented that diabetes impairs the microcirculation, its effect on isometric exercise has not been determined.Isometric strength and endurance of the handgrip muscles for a series of 2 fatiguing isometric contractions at a tension of 40% of the maximum strength were assessed in 10 subjects with Type 2 diabetes compared to 10 control subjects; 5 minutes were allowed between the contractions. Blood pressure (BP), heart rate (HR), blood flow (BF) of the whole arm and of the skin on the chest and foot were measured.Strength and endurance for the first contraction was the same in control subjects compared to subjects with Type 2 diabetes (p0.05), but endurance of the second contraction was significantly less in subjects with diabetes (p0.01). HR increased significantly (p0.01) by over three fold during exercise in control subjects compared to subjects with diabetes. Resting and peak blood pressures were greater in subjects with type 2 diabetes compared to control subjects (p0.01). Forearm blood flow was significantly lower at rest, during exercise and post exercise in subjects with diabetes compared to control subjects (p0.01).The results are probably explained by the damage to the microcirculation seen in subjects with diabetes.

While wounds heal more quickly when electrical stimulation (ES) is applied, few studies have examined blood flow (BF) in and around wounds during ES in controls with no wounds compared to wounds in diabetic and non diabetic subjects.Ten subjects with stage III and IV wounds and 8 controls were subjected to 5 minutes of biphasic ES (20 milliamps, pulse width 250 usec). Before, during, and after, BF were measured by a Laser Doppler Imager.For the control subjects, in the fingers, BF increased from 307 flux to 687 after 5 min of ES to one finger but BF also increased to other fingers indicating a reflex increase in flow mediated by the sympathetic nervous system. For hairy skin, there was a 12% increase in BF with ES and only in the line directly between the stimulating electrodes. For the patients (either with or without Type 2 diabetes), stimulation in the hand, leg and foot all caused a large increase in BF during and for 5 minutes after stimulation. In patients, BF was high in the wound area before ES and increased by 53% during, and remained high after stimulation was over.The results show that in wounds, where BF is high due to bradykinin and cytokine release, the vasoconstrictor tone is not present and electrical stimulation causes a large increase in circulation which lasts after stimulation is over.