The role of nitric oxide in skin blood flow increases due to vibration in healthy adults and adults with type 2 diabetes.

BACKGROUND: We recently demonstrated concomitant increases in skin blood flow and nitric oxide (NO) production in young healthy adults in response to externally applied vibration of the forearm. Research has shown that adults with type 2 diabetes exhibit depressed NO production and vascular responses to NO. We hypothesized that subjects with type 2 diabetes would display lower than normal increases in skin blood flow to externally applied vibration. RESEARCH DESIGN AND METHODS: Therefore, the purpose of this study was to compare 20 male and female, age- and body mass index-matched normal adults and adults with type 2 diabetes in terms of the effects of external vibration of the forearm on skin blood flow and the rate of NO production. Skin blood flow and NO production were measured before vibration, immediately after 5 min of vibration, and 5 min after vibration ceased. RESULTS: Although externally applied vibration significantly increased skin blood flow for both groups (P = 0.0001), those with diabetes had significantly lower (223%; P = 0.003) skin blood flows compared to the healthy older adults (461%). The rate of NO production, expressed as microM NO . flux, also increased significantly in both groups after vibration (healthy group, 374%; diabetes group, 236%) and remained significantly elevated (healthy group, 258%; diabetes group, 177%) for at least 5 min; however, the difference between groups was not significant (P = 0.12). CONCLUSIONS: These findings suggest that subjects with diabetes exhibit a lower skin blood flow and lower NO response to externally applied vibration than matched normal subjects.

The effect of 30 Hz vs. 50 Hz passive vibration and duration of vibration on skin blood flow in the arm.

BACKGROUND: Recently, researchers have demonstrated that Whole Body Vibration (WBV) results in significant increases in skin blood flow (SBF). No study has determined if a specific frequency or a specific duration is better at optimizing SBF. MATERIAL/METHODS: Two studies were conducted to determine, 1) if there is a difference in SBF due to passive vibration of the forearm at 30 Hz vs. 50 Hz, 2) if one frequency is superior, and 3) if there is an optimal duration. In the first study, 18 subjects (mean age 20.3+/-2.9 years) were randomly placed into a 30 Hz or 50 Hz vibration group, and in the second, seven subjects (mean age 23.3+/-3.8 years) participated in both 30 and 50 Hz vibration. Each subject's arm was passively vibrated for 10 minutes. SBF was examined during vibration and for 15 minutes of recovery. RESULTS: Both frequencies produced significant increases in SBF (p<0.05) within the first four minutes of vibration. Peak SBFs were obtained by the fifth minute. SBF remained high for minutes 4 through 10 of vibration in the second study. In the first study, SBF remained high for minutes 4 through 9. During recovery, 30 Hz vibration produced SBFs below baseline values while 50 Hz SBFs remained above baseline. Statistically one frequency was not superior to the other. CONCLUSIONS: Five minutes of 30 Hz or 50 Hz vibration produced significant increases in SBF. Clinically, 50 Hz has additional benefits because SBF increased more rapidly and did not result in vasoconstriction during the recovery period. Future studies should be done to determine if these increases in SBF could be of benefit to populations with low circulation such as those with diabetes.

The effect of whole body vibration on lower extremity skin blood flow in normal subjects.

BACKGROUND: Circulation plays a vital role in tissue healing. Increases in muscle flexibility and strength, secretion of hormones important in the regeneration and repair process, blood flow, and strength of bone tissues has been attributed to whole body vibration (WBV) combined with exercise. The purpose of the study was to determine the effects of short-duration, high-intensity, isometric weight bearing exercise (vibration exercise [VE]) and vibration only on skin blood flow (SBF). MATERIAL/METHODS: Forty-five subjects 18-43 years of age were randomly divided into three groups: Group 1 - VE, Group 2 - exercise only, and Group 3 - vibration only. SBF was measured using a laser Doppler imager at three time intervals: 1) initial base line, 2) immediately following intervention, and 3) 10-minutes following intervention. RESULTS: There was no significant difference between the three groups' SBF prior to intervention. Immediately following the intervention a difference among groups was found. Post hoc testing revealed that Group 3 subjects' mean SBF was significantly increased at both post-intervention time intervals. CONCLUSION: The study findings suggest that short duration vibration alone significantly increases SBF; doubling mean SBF for a minimum of 10 minutes following intervention. The emerging therapeutic modality of WBV as a passive intervention appears to increase SBF in individuals with healthy microcirculation.