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Imaging
Authors:
Takashi Abe
,
Vickie Wong
,
Zachary W. Bell
,
Robert W. Spitz
,
Scott J. Dankel
, and
Jeremy P. Loenneke

Abstract

Background

It has been observed that gluteal-femoral adipose tissue has a protective effect against risk factors for cardiovascular disease but has not yet been concluded how different evaluation methods of fat distribution affect the results.

Methods

To test the hypothesis that B-mode ultrasound-measured subcutaneous adipose tissue distribution is associated with cardiovascular risk factors, 326 Japanese unmedicated postmenopausal women aged 50–70 years were analyzed. Subcutaneous adipose tissue thickness at 6 sites (anterior and posterior aspects of trunk, upper-arm, and thigh) and serum total (TC) and high-density lipoprotein cholesterol (HDLC) was measured, and a ratio of HDLC to TC (HDLC/TC) was calculated. We used Bayesian linear regression with 4 separate models with each model predicting HDLC/TC.

Results

Our first model provided evidence for an inverse correlation (r = –0.23) between ultrasound measured body fat (6 site measurement) and HDLC/TC. The second model noted evidence for an inverse correlation between trunk fat and HDLC/TC and found evidence for the null with respect to the correlation between thigh fat and HDLC/TC. Therefore, we added thigh fat to the null model to produce Distribution Model 2. Within this model, we noted an inverse correlation (r = –0.353) between trunk fat and HDLC/TC. Our last model determined that within the trunk fatness, the abdominal area (anterior trunk) was a larger predictor than the subscapular site (posterior trunk).

Conclusion

These results support the evidence that ultrasound-measured abdominal subcutaneous adipose tissue thickness is a non-invasive predictor for monitoring the risk for dyslipidemia in postmenopausal women.

Open access
Physiology International
Authors:
Vickie Wong
,
Zachary W. Bell
,
Robert W. Sptiz
,
Jun Seob Song
,
Yujiro Yamada
,
Takashi Abe
, and
Jeremy P. Loenneke

Abstract

Background

Orthostatic intolerance occurs in some astronauts following space flight. Although orthostatic blood pressure responses should normalize in the weeks following the return to Earth, there may be situations where an immediate short-term solution is necessary (e.g., emergency evacuation).

Purpose

The purpose of this study was to examine different levels of blood flow restriction on changes in blood pressure and heart rate when transitioning from supine to a head-up tilt and determine whether this change differs based on sex.

Methods

Eighty-nine participants (45 men, 44 women) completed the three visits with different pressures (Sham, Moderate, and High) in a randomized order. Cuffs were placed on the most proximal area of the thighs. Brachial blood pressure was measured at baseline, upon inflation of the cuffs in a supine position, immediately after tilt (70°), and eight more times separated by 45  seconds.

Results

Data are presented as mean (SD). The change in systolic (High > Moderate > Sham) [High vs Sham: 5.5 (7.4) mmHg, High vs Moderate: 3 (7.4) mmHg, and Moderate vs Sham: 2.4 (8.4) mmHg] and diastolic pressure (High > Moderate = Sham) [High vs Sham: 2.4 (5.3) mmHg, High vs Moderate: 1.9 (6.3) mmHg] differed across applied pressures. The change in heart rate was initially greatest in the sham-pressure but increased the greatest in the high-pressure condition by the end of the head-up tilt period. Additionally, there was no influence of sex.

Conclusion

Blood flow restriction applied in this study increased blood pressure in a pressure-dependent manner upon head-up tilt.

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Physiology International
Authors:
Robert W. Spitz
,
Jun Seob Song
,
Yujiro Yamada
,
Vickie Wong
,
Zachary W. Bell
,
Ryo Kataoka
, and
Jeremy P. Loenneke

Abstract

Previous work has found that wide cuffs produce greater discomfort with elbow flexion exercise than narrower cuffs. It is our hypothesis that this is due to the balling up of the biceps underneath the cuff that is more pronounced with a wider cuff. One method to test this is through an upper body exercise where there is no contraction of the biceps.

Purpose

To investigate the effects of cuff width on discomfort following isometric handgrip exercise.

Methods

One hundred participants completed this experiment. In a randomized order, the participants performed four sets of two-minute isometric handgrip contractions with thirty seconds of rest at thirty percent of their maximal voluntary contraction with a 5 and 12 cm cuff inflated to 40% of arterial occlusion pressure. Discomfort ratings (0–100) were given after the fourth set of exercise. Average force was recorded for all four sets.

Results

There was no difference in discomfort (BF10 = 0.158) [median difference (95% credible interval) −0.997 (−3.360, 1.283) arbitrary units], or in average force (BF10 = 0.132) [median difference (95% credible interval) 0.08 (−0.199, 0.372) kilograms], between cuff conditions. There did not appear to be a greater preference for either cuff. Forty people preferred the narrow cuff (BF10 = 0.325), forty people preferred the wide cuff (BF10 = 0.325), and twenty people had no preference (BF10 = 7.719).

Conclusion

Cuff width does not appear to influence discomfort or the average force produced. This provides support for our hypothesis that the shape of the muscle may interact with wider cuff sizes, leading to greater discomfort.

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