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Objective: Evidence is accumulating, predominantly among clinical trials in adults, that yoga improves blood pressure (BP) control, with downregulation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS) projected as underlying mechanisms. This pilot study assessed whether Hatha yoga has the potential to reduce BP among youth and whether dampening of the SNS and/or HPA activity is a likely pathway of change. Design: Thirty-one seventh graders were randomly assigned to a Hatha yoga program (HYP) or attention control (AC) music or art class. Baseline and 3-month evaluations included resting BP; overnight urine samples; and saliva collected at bedtime, upon awakening, and at 30 and 60 minutes after awakening for a-amylase and cortisol assays. Results: Twenty-eight (14 in the HYP group and 14 in the AC group) students were assessed both before and after the intervention. BP changes from pre-to post-intervention were -3.0/ -2.0 mmHg for the HYP group and -0.07/ -0.79 mmHg for the AC group (p = 0.30 and 0.57, respectively). Changes in systolic BP (SBP)/diastolic BP (DBP) for the prehypertensive (75th-94th percentiles for SBP) subgroup analyses were -10.75/ -8.25 mmHg for the HYP group (n = 4) versus 1.8/1.0 mmHg for the AC group (n = 5) ( p for SBP = 0.02; p for DBP = 0.09). Although no statistically significant group differences were observed with changes in SNS or HPA awakening curves (area under curve for a-amylase and cortisol, respectively), a small to moderate effect size was seen favoring a reduction of a-amylase activation for the HYP group (Cohen d = 0.34; prehypertensive d = 0.20). Conclusions: A school-based Hatha yoga program demonstrated potential to decrease resting BP, particularly among prehypertensive youth. Reduced SNS drive may be an underlying neurohormonal pathway beneficially affected by the program. A large-scale efficacy/effectiveness randomized clinical trial is warranted.

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The molten salt pump and valve (P&V) test loops at Sandia National Laboratories (SNL) National Solar Thermal Test Facility (NSTTF) operated between Jan. 1988 and Oct. 1990. The purpose of the P&V test was to demonstrate the performance, reliability, and service life of full-scale hot and cold salt pumps and valves for use in commercial central receiver solar power plants. The P&V test hardware consists of two pumped loops; the “Hot Loop” to simulate the hot (565°C) side of the receiver and the “Cold Loop” to simulate the receiver’s cold (285°C) side. Each loop contains a pump and five valves sized to be representative of a conceptual 60-MWe commercial solar power plant design. The hot loop accumulated over 6700 hours of operation and the cold loop over 2500 hours of operation. This project has demonstrated that standard commercial scale pump and valve designs will work in molten salt. The test also exposed some pitfalls that must be avoided in specifying such equipment. Although certainly not all of the pitfalls were discovered, careful design and specification should result in reliable or at least workable equipment.

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