High-Intensity interval training reduces transcriptomic age: A randomized controlled trial.

While the relationship between exercise and life span is well-documented, little is known about the effects of specific exercise protocols on modern measures of biological age. Transcriptomic age (TA) predictors provide an opportunity to test the effects of high-intensity interval training (HIIT) on biological age utilizing whole-genome expression data. A single-site, single-blinded, randomized controlled clinical trial design was utilized. Thirty sedentary participants (aged 40-65) were assigned to either a HIIT group or a no-exercise control group. After collecting baseline measures, HIIT participants performed three 10 × 1 HIIT sessions per week for 4 weeks. Each session lasted 23 min, and total exercise duration was 276 min over the course of the 1-month exercise protocol. TA, PSS-10 score, PSQI score, PHQ-9 score, and various measures of body composition were all measured at baseline and again following the conclusion of exercise/control protocols. Transcriptomic age reduction of 3.59 years was observed in the exercise group while a 3.29-years increase was observed in the control group. Also, PHQ-9, PSQI, BMI, body fat mass, and visceral fat measures were all improved in the exercise group. A hypothesis-generation gene expression analysis suggested exercise may modify autophagy, mTOR, AMPK, PI3K, neurotrophin signaling, insulin signaling, and other age-related pathways. A low dose of HIIT can reduce an mRNA-based measure of biological age in sedentary adults between the ages of 40 and 65 years old. Other changes in gene expression were relatively modest, which may indicate a focal effect of exercise on age-related biological processes.

Predictors of Biological Age: The Implications for Wellness and Aging Research.

As healthspan and lifespan research breakthroughs have become more commonplace, the need for valid, practical markers of biological age is becoming increasingly paramount. The accessibility and affordability of biological age predictors that can reveal information about mortality and morbidity risk, as well as remaining years of life, has profound clinical and research implications. In this review, we examine 5 groups of aging biomarkers capable of providing accurate biological age estimations. The unique capabilities of these biomarkers have far reaching implications for the testing of both pharmaceutical and non-pharmaceutical interventions designed to slow or reverse biological aging. Additionally, the enhanced validity and availability of these tools may have increasingly relevant clinical value. The authors of this review explore those implications, with an emphasis on lifestyle modification research, and provide an overview of the current evidence regarding 5 biological age predictor categories: Telomere length, composite biomarkers, DNA methylation "epigenetic clocks," transcriptional predictors of biological age, and functional age predictors.

Effects of smartphone addiction on children's lung function.

BACKGROUND: With an increase in smartphone usage, constant neck flexion can lead to improper posture, which may impact on lung function. Therefore, the purpose of this study was to examine and compare the craniovertebral angle (CVA) and lung function between addicted and non-addicted boys and girls aged between 8-13 years who use smartphones for long periods of time. METHODS: A cross-sectional study was conducted on 24 boys and 26 girls (mean age 10.5 ± 1.6 years and body mass index 18.6 ± 3.0 kg/m2) . Participants were assigned to two groups based on their scores on the Smartphone Addiction Scale-Short Version (SAS-SV) for Adolescents: addicted group (score > 32, n = 32) and non-addicted group (score ≤ 32, n = 18). The outcome variables were CVA, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), maximal voluntary ventilation (MVV), maximum inspiratory pressures (PImax), and maximum expiratory pressures (PEmax). RESULTS: There was a significant difference in mean CVA between addicted and non-addicted boys (49.4 ± 6.7 vs 55.5 ± 7.6, η2  = 0.9, P = 0.03) and girls (47.3 ± 6.3 vs 52.9 ± 6.1, η2  = 0.9, P = 0.02). Mean FVC, FEV1, and FEV6 were significantly lower in addicted versus non-addicted boys (P = 0.04, P = 0.05, and P = 0.02, respectively). PImax was significantly less in addicted compared to non-addicted girls (55.2 ± 16.4 vs 65.3 ± 13.8, η2  = 0.7, P = 0.05). CONCLUSION: Our findings showed that children addicted to smartphones (when using the SAS-SV as an indicator for addiction) revealed lower CVA and lung function results. Therefore, education on proper posture while holding smartphones is essential to the children's postural and lung function status.

Improved balance in middle-aged adults after 8 weeks of a modified version of Otago Exercise Program: A randomized controlled trial.

OBJECTIVE: The objective of this randomized controlled trial was to examine dynamic balance changes (reach distance) in middle-aged adults using the Y Balance Test (YBT) following 8 weeks of home-based exercise program adapted from the Otago Exercise Program (OEP). METHODS: Fifty-two healthy middle-aged adults with mean age of 54.4±5.4 years and body mass index of 27.7±5.7 kg/m2 were randomly assigned into either the exercise group (a modification of the Otago Exercise Program, that consisted of home-based balance and strength exercises) or the non-exercise group (continuation of usual lifestyle) by having the participants select a paper from a sealed envelope. The YBT was used to measure participants' dynamic balance in the right and left anterior (RA, LA), posteromedial (RPM, LPM), and posterolateral (RPL, LPL) directions. RESULTS: The outcome in this trial was reach distance (cm). There was a significant group by time interaction in terms of reach distance for all directions (p<0.05, η2 ranged from 0.06 to 0.20). In the exercise group, results of the repeated measures analysis of variance (ANOVA) showed significant improvements in the reach distance in all the directions (p<0.001). In contrast, the non-exercise group had significant difference only in the left posterolateral direction (p = 0.009). Participants in the exercise group achieved significantly greater reach distance (cm) (95% confidence interval (CI)) for RA[(2.8, 0.4 to 5.2), p = 0.023]; LA[(3.2, 0.9 to 5.6), p = 0.008]; RPM[(4.0, 1.0 to 7.9), p = 0.046]; LPM[(5.8,1.3 to 10.3), p = 0.013]; RPL[(7.6, 2.6 to 12.6), p = 0.003]; and LPL[(4.2, 0.3 to 8.2), p = 0.035]. CONCLUSION: The modified version of OEP appears to be effective in improving parameters of dynamic balance in the middle-aged adult population. The improvements in YBT reach distance in the exercise group are indicative of the significance of performing balance and strength exercises regularly for this population.

Neuromuscular control of ankle and hip during performance of the star excursion balance test in subjects with and without chronic ankle instability.

BACKGROUND/PURPOSE: Ankle sprains are common and potentially disabling musculoskeletal injuries that often lead to chronic ankle instability (CAI). CAI has been linked to impairments in postural and neuromuscular control; however, inconsistent findings have been reported. Individuals who experience a lateral ankle sprain, but do not develop instability, termed copers, may adapt different neuromuscular control strategies after injury. This study aimed to compare postural control and electromyographic (EMG) activity of hip and ankle muscles during the performance of the Star Excursion Balance Test (SEBT) in subjects with and without CAI. METHOD: 48 participants were classified into three groups (16 control, 16 copers, 16 CAI) based on ankle sprain history and Cumberland Ankle Instability Tool score. Outcome measures included normalized reach distance, center of pressure (COP), and integrated EMG activation of gluteus medius (Gmed), gluteus maximus (Gmax), tibialis anterior (TA), and peroneus longus (PL) during each reach direction of SEBT. RESULTS: Compared to copers and controls, CAI group demonstrated significantly diminished postural control (reach distance and COP measures, p< 0.05) and less EMG activity of TA during the anterior direction (CAI: 33.1% ± 10.1% versus copers: 44.8% ± 12.7% versus controls: 51.7% ± 8.4%, p<0.01) and Gmax in the posterolateral direction (CAI: 25.6% ± 9.4% versus copers: 37.5% ± 13.8% versus controls: 40.2% ± 17.2%, p = 0.011). CONCLUSION: Alteration in proximal and distal muscle activity appears to negatively affect postural control and quality of movement, which may lead to prolonged functional impairments. Hence, implementing hip and ankle muscle exercises in the rehabilitation of ankle instability might benefit these patients.

The Efficacy of Sustained Heat Treatment on Delayed-Onset Muscle Soreness.

OBJECTIVE: To assess the impact of heat applied for 8 hours immediately after or 24 hours after exercise on delayed-onset muscle soreness (DOMS) in large skeletal muscle groups measured by subjective and objective means. DESIGN: Cross-sectional repeated measure design study. SETTING: Research laboratory. SUBJECTS: Three groups of 20 subjects, age range 20 to 40 years. INTERVENTION: Squats were conducted in three 5-minute bouts to initiate DOMS; 3 minutes of rest separated the bouts. One group had heat applied immediately after exercise, and a second group had heat applied 24 hours after exercise. A third group was the control group where no heat was applied. MAIN OUTCOME MEASURES: Visual analog pain scales, muscle strength of quads, range of motion of quads, stiffness of quads (Continuous Passive Motion machine), algometer to measure quadriceps soreness, and blood myoglobin. RESULTS: The most significant outcome was a reduction in soreness in the group that had low-temperature heat wraps applied immediately after exercise (P < 0.01). There was benefit to applying heat 24 hours after exercise, but to a smaller extent. This was corroborated by myoglobin, algometer, and stiffness data. CONCLUSIONS: Low-level continuous heat wraps left for 8 hours just after heavy exercise reduced DOMS in the population tested as assessed by subjective and objective measures. CLINICAL RELEVANCE: Although cold is commonly used after heavy exercise to reduce soreness, heat applied just after exercise seems very effective in reducing soreness. Unlike cold, it increases flexibility of tissue and tissue blood flow. For joint, it is still probably better to use cold to reduce swelling.

Effect of ThermaCare HeatWraps and Icy Hot Cream/Patches on Skin and Quadriceps Muscle Temperature and Blood Flow.

OBJECTIVES: The purpose of this study was to compare the effects of over-the-counter treatments-ThermaCare HeatWraps (chemical reaction to produce heat above the skin), Icy Hot Patch, and Icy Hot Cream (topically applied menthol)-on skin and deep tissue temperature. METHODS: This was a longitudinal crossover study. On each of 3 days, a ThermaCare HeatWrap, Icy Hot Cream, or Icy Hot Patch was applied randomly over the quadriceps muscle in 15 healthy volunteers with normal body mass. Skin and muscle temperature and blood flow were measured by laser flowmetry every 15 minutes for 2 hours. RESULTS: After 2 hours, mean temperature decreased by 2.1°C (7.0%; P = .02) in skin and 1.0°C (2.9%; P = .01) in muscle with Icy Hot Cream. Icy Hot Patch decreased skin and muscle temperature by 1.7°C (5.4%; P = .03) and 1.3°C (3.8%; P = .01), respectively. In contrast, ThermaCare raised skin and muscle temperature by 7.8°C (25.8%; P = .001) and 2.7°C (7.7%; P = .002), respectively; both were significantly warmer with ThermaCare vs either Icy Hot product (all P < .007). Icy Hot products produced a net decrease in skin blood flow (Cream: 56.7 flux [39.3%; P = .003]; Patch: 19.1 flux [16.7%; P = .045]). Muscle blood flow decreased with the Patch (6.7 flux [7.0%; P = .02]). After a period of fluctuations, Icy Hot Cream produced a net increase vs baseline of 7.0 flux (16.9%; P = .02). ThermaCare more than doubled blood flow in skin (83.3 flux [109.7%; P = .0003]) and muscle (25.1 flux [148.5%; P = .004]). CONCLUSIONS: In this group of 15 healthy volunteers, ThermaCare HeatWraps provided the greatest degree of tissue warming and increase in tissue blood flow.

Cold Vs. Heat After Exercise-Is There a Clear Winner for Muscle Soreness.

Because of the differences in the exercise type, temperature, and timing of the use of cold and heat after exercise in different studies, there is no clear conclusion as to the efficacy of either modality on reducing delayed onset muscle soreness. One hundred subjects at similar fitness levels were examined. They accomplished leg squats for 15 minutes and heat and cold were applied after or 24 hours after exercise using ThermaCare heat or cold wraps. Measurements obtained were strength, the force to passively move the knee, analog visual pain scales, and blood myoglobin. Control subjects lost 24% strength after exercise. Subjects with heat or cold just after exercise only lost 4% strength (p < 0.01). For strength recovery, cold applied after 24 hours was better than heat at 24 hours. Heat or cold applied after exercise was significantly better to prevent elastic tissue damage (p < 0.01), whereas heat and cold immediately after exercise caused no loss in muscle myoglobin and heat or cold after 24 hours showed no less muscle damage from myoglobin than in control subjects. Myoglobin in the control and heat and cold 24-hour groups averaged 135.1% of the baseline data but averaged 106.1% of baseline in the immediate heat and cold groups. For reducing pain, control subjects showed a significant amount of pain the days after exercise. But cold immediately after exercise or 24 hours later was superior to heat in reducing pain. In conclusion, both cold and heat appear to be efficacious in reducing muscle damage after exercise.

Humors Effect on Short-term Memory in Healthy and Diabetic Older Adults.

CONTEXT: With aging, the detrimental effects of stress can impair a person's ability to learn and sustain memory. Humor and its associated mirthful laughter can reduce stress by decreasing the hormone cortisol. Chronic release of cortisol can damage hippocampal neurons, leading to impairment of learning and memory. Objectives • The study intended to examine the effect of watching a humor video on short-term memory in older adults. Design • The research team designed a randomized, controlled trial. SETTING: The study took place at Loma Linda University in Loma Linda, CA, USA. PARTICIPANTS: The study included 30 participants: 20 normal, healthy, older adults-11 males and 9 females-and 10 older adults with type 2 diabetes mellitus (T2DM)-6 males and 4 females. INTERVENTION: The study included 2 intervention groups of older adults who viewed humorous videos, a healthy group (humor group), aged 69.9 ± 3.7 y, and the diabetic group, aged 67.1 ± 3.8 y. Each participant selected 1 of 2 humorous videos that were 20 min in length, either a Red Skeleton comedy or a montage of America's Funniest Home Videos. The control group, aged 68.7 ± 5.5 y, did not watch a humor video and sat in quiescence. OUTCOME MEASURES: A standardized, neuropsychological, memory-assessment tool, the Rey Auditory Verbal Learning Test (RAVLT), was used to assess the following abilities: (1) learning, (2) recall, and (3) visual recognition. The testing occurred twice, once before (RAVLT1) and once after (RAVLT2) the humorous video for the humor and diabetic groups, and once before (RAVLT1) and once after (RAVLT2) the period of quiescence for the control group. At 5 time points, measurements of salivary cortisol were also obtained. The Kruskal-Wallis test was used to measure significance of the data based on the 3 groups. RESULTS: In the humor, diabetic, and control groups, (1) learning ability improved by 38.5%, 33.4%, and 24.0%, respectively (P = .025); (2) delayed recall improved by 43.6%, 48.1%, and 20.3%, respectively (P = .064); and (3) visual recognition increased by 12.6%, 16.7%, and 8.3%, respectively (P = .321). For levels of salivary cortisol, the research team found significant and borderline decreases for the humor group between baseline and (1) post-RAVLT1 (P = .047), (2) postvideo (P = .046), and (3) post-RAVLT2 (P = .062). The diabetic group showed significant decreases between baseline and (1) post-RAVLT1 (P = .047), (2) postvideo (P = .025), and (3) post-RAVLT2 (P = .034). The study found no significant changes for the control group. CONCLUSION: The research findings supported potential clinical and rehabilitative benefits for humor that can be applied to whole-person wellness programs for older adults. The cognitive components-learning ability and delayed recall-become more challenging as individuals age and are essential to older adults for providing a high quality of life: mind, body, and spirit. Because older adults can experience age-related memory deficits, complementary, enjoyable, and beneficial humor therapies should be implemented for them.

Continuous low-level heatwrap therapy relieves low back pain and reduces muscle stiffness.

BACKGROUND: Low back pain is a common and costly health care problem. This pilot study evaluated the sensitivity of the 2-stopwatch and Paris plinth methodologies for assessing time-to-onset of pain relief and flexibility, respectively, with continuous, low-level heatwrap therapy. RESEARCH DESIGN AND METHODS: Subjects aged 18 to 55 years with at least moderate baseline acute low back pain were randomly assigned to either heatwrap or oral placebo for 8 hours. Unheated wrap (sham) and oral ibuprofen were included for blinding purposes only. RESULTS: Sixty-one subjects were randomly assigned to either heatwrap (n = 26), oral placebo (n = 25), sham wrap (n = 5), or oral ibuprofen (n = 5). Median time to confirmed first perceptible pain relief and to meaningful pain relief were significantly shorter for the heatwrap group compared with those assigned to oral placebo (96.5 vs > 240.0 min and 215.7 vs > 240.0 min, respectively; P < 0.05 for both). Among subjects receiving the heatwrap, 53.8% reported first perceptible and meaningful relief, compared with 28.0% receiving oral placebo. Subjective measures of pain relief, back stiffness, and global evaluation were more sensitive in detecting treatment differences than the plinth assessments of flexibility, range of motion, and pain. Three adverse events were reported as mild in severity and considered unrelated to study treatment. CONCLUSIONS: The 2-stopwatch methodology is a viable approach for assessing onset of analgesia in low back pain; however, the plinth may not be a reliable method for assessing flexibility. Consistent with published studies involving much larger sample sizes, the heatwrap provided significantly faster and sustained pain relief than oral placebo in subjects with acute low back pain. Clinical Trial Identifier: NCT01045993.

The effect of humor on short-term memory in older adults: a new component for whole-person wellness.

CONTEXT: For older adults, the damaging effects of aging and stress can impair the ability to learn and sustain memory. Humor, with its associated mirthful laughter, can reduce stress and cortisol, a stress hormone. Chronic release of cortisol can damage hippocampus neurons, leading to impairment of learning and memory. OBJECTIVES: The primary goal of this study was to determine whether watching a humorous video had an effect on short-term memory in an older population. DESIGN: The research team designed a randomized, controlled trial. SETTING: The study took place at Loma Linda University in Loma Linda, California. PARTICIPANTS: The research team recruited 20 normal, healthy, older adults, 11 males and 9 females. INTERVENTION: The humor group (n = 10, mean = 69.3 ± 3.7 y) self-selected 1 of 2 humorous videos--a Red Skelton comedy or a montage of America's Funniest Home Videos--and watched it for 20 min. A control group (n = 10, mean = 68.7 ± 5.5 y) sat calmly for 20 min and were not allowed to read, sleep, or talk on a cell phone. OUTCOME MEASURES: The Rey Auditory Verbal Learning Test was used to assess short-term memory--learning ability, delayed recall, and visual recognition. Salivary cortisol levels were measured at predetermined times. RESULTS: Learning ability improved by 38.5% and 24.0% in the humor and control groups, respectively (P = .014). Delayed recall improved by 43.6% and 20.3% in the humor and control groups, respectively (P =.029). Within the humor group, delayed recall (43.6%) was significant compared with learning ability (38.5%) (P = .002). At 3 predetermined time points, significant decreases in salivary cortisol were observed in the humor group (P = .047, P = .046, and P = .062, respectively). CONCLUSION: The study's findings suggest that humor can have clinical benefits and rehabilitative implications and can be implemented in programs that support whole-person wellness for older adults. Learning ability and delayed recall are important to these individuals for a better quality of life--considering mind, body, spirit, social, and economic aspects. Older adults may have age-associated memory deficiencies. However, medical practitioners now can offer positive, enjoyable, and beneficial humor therapies to improve these deficiencies.

Moist heat or dry heat for delayed onset muscle soreness.

BACKGROUND: Heat is commonly used in physical therapy following exercise induced delayed onset muscle soreness (DOMS). Most heat modalities used in a clinical setting for DOMS are only applied for 5 to 20 minutes. This minimal heat exposure causes little, if any, change in deep tissue temperature. For this reason, long duration dry chemical heat packs are used at home to slowly and safely warm tissue and reduce potential heat damage while reducing pain associated from DOMS. Clinically, it has been shown that moist heat penetrates deep tissue faster than dry heat. Therefore, in home use chemical moist heat may be more efficacious than dry heat to provide pain relief and reduce tissue damage following exercise DOMS. However, chemical moist heat only lasts for 2 hours compared to the 8 hours duration of chemical dry heat packs. The purpose of this study was to compare the beneficial effect of dry heat versus moist heat on 100 young subjects after exercise induce DOMS. METHODS: One hundred subjects exercised for 15 minutes accomplishing squats. Before and for 3 days after, strength, muscle soreness, tissue resistance, and the force to passively move the knee were recorded. Heat and moist heat were applied in different groups either immediately after exercise or 24 hours later. RESULTS: The research results of this study showed that immediate application of heat, either dry (8 hours application) or moist (2 hours application), had a similar preservation of quadriceps muscle strength and muscle activity. Results also revealed that the greatest pain reduction was shown after immediate application of moist heat. Never the less, immediate application of dry heat had a similar effect but to a lesser extent. CONCLUSION: It should be noted that moist heat had not only similar benefits of dry heat but in some cases enhanced benefits, and with only 25% of the time of application of the dry heat.

What is more damaging to vascular endothelial function: Diabetes, age, high BMI, or all of the above?

BACKGROUND: It is well established that there is a reduction in the skin blood flow (SBF) in response to heat with age and diabetes. While it is known that high BMI creates a stress on the cardiovascular system and increases the risk of all cause of morbidity and mortality, little is known of the effect of high BMI on SBF response to heat. Since diabetes is associated with age and a higher BMI, the interrelationship between age, BMI and SBF needs to be investigated to better understand the contribution diabetes alone has to endothelial impairment. MATERIAL AND METHODS: This study examined the SBF to heat in young and old people with low and high BMI and people with diabetes with high BMI to determine the contribution these variables have on SBF. Subjects were ten young and older people with BMI <20 and ten young and older people with BMI >20 and ten subjects with diabetes with BMI >20. The SBF response, above the quadriceps, was determined during a 6 minutes exposure to heat at 44°C. RESULTS: Even in young people, SBF after the stress of heat exposure was reduced in subjects with a high BMI. The effect of BMI was greatest in young people and lowest in older people and people with diabetes; in people with diabetes, BMI was a more significant variable than diabetes in causing impairment of blood flow to heat. BMI, for example, was responsible for 49% of the reduction in blood flow after stress heat exposure (R=-0.7) while ageing only accounted for 16% of the blood flow reduction (R=-0.397). CONCLUSIONS: These results would suggest the importance of keeping BMI low not only in people with diabetes to minimize further circulatory vascular damage, but also in young people to diminish long term circulatory vascular compromise.

Electroencephalography to assess motor control during balance tasks in people with diabetes.

BACKGROUND: Balance is sensed through peripheral and central receptors and mediated by central control through the brain and spinal cord. Although some evidence exists as to the areas of the brain involved and how processing of data occurs in young individuals, nothing has been published on people with diabetes. The purpose of this study was to examine the electroencephalogram (EEG) during common sensorimotor and balance training tasks and to relate these to task difficulty. SUBJECTS AND METHODS: Postural sway and EEG change of alpha, beta, and sigma wave bands were measured in 17 young subjects, 10 older subjects, and 10 subjects with diabetes during eight progressively more difficult balance tasks with eyes open and closed, feet in tandem or apart, and on foam or a firm surface. RESULTS: EEG power of beta and sigma wave bands showed significant increases on the cortical and parietal areas of the brain relative to the control tasks when eyes were open (P<0.05). The cortical involvement decreased as the task became more difficult with vision and somatosensory information reduced, whereas that of the parietal area increased with task difficulty. The greatest increase was in subjects with diabetes, and the least was in younger people. Individuals with diabetes had increased sigma and beta EEG power in all regions of the brain examined with increased complexity of the balance task. CONCLUSIONS: This study demonstrated cortical and parietal involvement in static balance tasks commonly used in sensorimotor training. The results support the proposal that there was increased subcortical control with increase in task difficulty in the young subjects, but in subjects with diabetes, there was a major increase in activity across the brain.

A comparison of whole body vibration and moist heat on lower extremity skin temperature and skin blood flow in healthy older individuals.

BACKGROUND: Tissue healing is an intricate process that is regulated by circulation. Heat modalities have been shown to improve skin circulation. Recent research supports that passive vibration increases circulation without risk of burns. Study purpose is to compare and determine effects of short duration vibration, moist heat, and a combination of the two on skin blood flow (SBF) and skin temperature (ST) in elderly, non-diabetic individuals following short-term exposure. MATERIAL/METHODS: Ten subjects, 3 female and 7 male (55-73 years of age), received two interventions over three days: 1--Active vibration, 2--passive vibration, 3--moist heat, 4--moist heat combined with passive vibration (MHPV), 5--a commercial massaging heating pad, and 6--no intervention. SBF and ST were measured using a MOOR Laser Doppler before and after the intervention and the third measurement were taken 10 minutes following. RESULTS: Mean SBF following a ten-minute intervention were significantly different in the combination of moist heat and passive vibration from the control, active vibration, and the commercial massaging heating pad. Compared to baseline measurements, this resulted in mean SBF elevation to 450% (at conclusion of 10 minutes of intervention) and 379% (10 minutes post). MHPV (p=0.02) showed significant changes in ST from the commercial massaging heating pad, passive vibration, and active vibration interventions. CONCLUSIONS: SBF in the lower legs showed greatest increase with MHPV. Interventions should be selected that are low risk while increasing lower extremity skin blood flow.

A comparison of the effect of a variety of thermal and vibratory modalities on skin temperature and blood flow in healthy volunteers.

BACKGROUND: Circulation plays an essential role in tissue healing. Moist heat and warm water immersion have been shown to increase skin circulation; however, these heating modalities can cause burns. Recent research has shown that passive vibration can also increase circulation but without the risk of burns. MATERIAL/METHODS: The aim of this study is to compare the effects of short-duration vibration, moist heat, and a combination of the two on skin blood flow (SBF) and skin temperature (ST). Ten (10) subjects, 5 female and 5 male, aged 20-30 years of age, received two interventions a day for 3 consecutive days: Intervention 1--Active vibration only (vibration exercise), Intervention 2--passive vibration only, Intervention 3--moist heat only, Intervention 4--passive vibration combined with moist heat, Intervention 5--a commercial massaging heating pad, and Intervention 6--no intervention, resting in supine only (control). SBF and ST were measured using a laser Doppler imager during the 10 minute intervention and then throughout the nine minute recovery period. RESULTS: The mean skin blood flow following a ten-minute intervention of the combination of passive vibration and moist heat was significantly different from the control, active vibration, and the commercial massaging heating pad. Skin temperature following the ten-minute interventions of moist heat alone and passive vibration alone were both significantly different from the commercial massaging heating pad and active vibration interventions. CONCLUSIONS: The combination of passive vibration and moist heat produced the greatest increase in skin blood flow and the second highest increase in skin blood flow nine minutes post application.

Autonomic stress and balance--the impact of age and diabetes.

INTRODUCTION: Balance is impaired in the elderly and people with diabetes. However, the effect of attempted balance on the autonomic nervous system has not been investigated. METHODS: Ten control subjects, 10 subjects with type 2 diabetes (age range, 21-75 years), and 10 older subjects age-matched to the subjects with diabetes were examined to determine the effect of diabetes and age on balance and the associated autonomic stress. Subjects were asked to stand on a balance platform for 1-min periods under four conditions: (1) quiet standing, (2) quiet standing with eyes closed, (3) quiet standing eyes closed with the platform allowed to move side to side over a central pivot that allows the edge of the platform to rotate 4 inches up and down, and (4) the same platform with eyes closed. Blood pressure, electrocardiogram, and sway were recorded. RESULTS: Balance was worst in the subjects with diabetes, while the cardiovascular stress, as assessed by both heart rate and blood pressure, was greatest in the older group of subjects. But subjects with diabetes, while having a greater blood pressure response to the stress induced by balance, showed a poor heart rate response, probably due to diabetes-induced autonomic damage. CONCLUSION: Autonomic damage in the subjects with diabetes masked much of the stress of the inability to optimize balance in this population.

Impact of hydrotherapy on skin blood flow: How much is due to moisture and how much is due to heat?

Hydrotherapy and whirlpool are used to increase skin blood flow and warm tissue. However, recent evidence seems to show that part of the increase in skin blood flow is not due to the warmth itself but due to the moisture content of the heat. Therefore, two series of experiments were accomplished on 10 subjects with an average age of 24.2 +/- 9.7 years and free of diabetes and cardiovascular disease. Subjects sat in a 37 degrees C hydrotherapy pool under two conditions: one in which a thin membrane protecting their skin from moisture while their arm was submerged in water and the second where their arm was allowed to be exposed to the water for 15 minutes. During this period of time, skin and body temperature were measured as well as skin blood flow by a Laser Doppler Imager. The results of the experiments showed that the vapor barrier blocked any change in skin moisture content during submersion in water, and while skin temperature was the same as during exposure to the water, the blood flow with the arm exposed to water increased from 101.1 +/- 10.4 flux to 224.9 +/- 18.2 flux, whereas blood flow increased to only 118.7 +/- 11.4 flux if the moisture of the water was blocked. Thus, a substantial portion of the increase in skin blood flow associated with warm water therapy is probably associated with moisturizing of the skin rather than the heat itself.

The effect of body fat, aging, and diabetes on vertical and shear pressure in and under a waist belt and its effect on skin blood flow.

BACKGROUND: Much attention has been given to the effect of pressure on skin blood flow in the feet of older people and people with diabetes. However, little attention has been paid to other areas of the body, especially under the belt at the waist where pressure might be high during body movements associated with exercise. This may be very important when devices such as heat packs are worn during the day under the belt because their safety relies on appropriate skin blood flow to dissipate the heat; in diabetes populations burns have been seen. METHODS: Forty male and female subjects, with and without diabetes, were examined in two series of experiments to assess the vertical and shear pressure under a belt worn during different common exercises. Vertical and shear pressure under the belt, belt tension, and shear pressure were measured with a Tactilus (Sensor Products, Madison, NJ) pressure mapping system. Eleven different body movements were examined. Then, from the recorded pressures, a second series of experiments examined skin blood flow at these same pressures. RESULTS: The results of the experiments showed that there was little shear and vertical pressure in thin subjects during 10 different exercises. However, for overweight subjects, pressure under the belt was as high as 150 kPa. At these high levels of pressure, skin circulation was occluded. CONCLUSIONS: In subjects with diabetes who are generally overweight and have impaired circulation, hot packs should be used with caution because of the low blood flows at rest and occlusion of the circulation under the belt with body movement.

Multiple stressors and the response of vascular endothelial cells: the effect of aging and diabetes.

BACKGROUND: The present study examined the effects of local heat, global heat, and the interaction between these two endothelial stressors on the blood flow of the skin of the foot in people who are older and who have diabetes. METHODS: Subjects who were older (mean age 64.2 +/- 5.9 years) and were younger (mean age 25.7 +/- 2.9 years) and subjects who had diabetes (mean age 62 +/- 5.9 years, mean duration 13.2 +/- 9.1 years) participated. Subjects were exposed to three global temperatures (16 degrees C, 24 degrees C, and 32 degrees C), and the blood flow response was recorded on the foot with a laser Doppler flow meter for 30 s following applications of local heat (30 degrees C, 33.5 degrees C, and 37 degrees C) using a Peltier junction to clamp the skin for 2 min. RESULTS: All three groups significantly increased blood flow from the 16-24 degrees C environments for the 37 degrees C application of local heat (P(Younger) = 0.02, P(Older) = 0.02, P(Diabetes) = 0.01). Those with diabetes and those who were older only increased blood flow 5% and 6% from the 24-32 degrees C environment, which was not statistically significant (P(Older) = 0.12, P(Diabetes) = 0.14). CONCLUSIONS: There appears to be considerable blood flow reserve in younger subjects to tolerate heat stress. In contrast, older subjects and those with diabetes reach a critical level after which additional heat does not cause in increase in blood flow.