The heart and blood vessels comprise the two elements of the cardiovascular system that work together in providing nourishment and oxygen to the organs of the body. The activity of these two elements is also coordinated in the body's response to stress. Acute stress — stress that is momentary or short-term such as meeting deadlines, being stuck in traffic or suddenly slamming on the brakes to avoid an accident — causes an increase in heart rate and stronger contractions of the heart muscle, with the stress hormones — adrenaline, noradrenaline and cortisol — acting as messengers for these effects. In addition, the blood vessels that direct blood to the large muscles and the heart dilate, thereby increasing the amount of blood pumped to these parts of the body and elevating blood pressure. This is also known as the fight or flight response. Once the acute stress episode has passed, the body returns to its normal state.
Maybe students that applied for vouchers were attending excellent public schools rather than mediocre or bad ones, so the private schools that received voucher students were up against the cream of Louisiana public schools. The Abdulkdiroglu et al. study rejected this hypothesis with the finding that Louisiana public schools attended by students applying for a voucher were below average in the state. On the recent NAEP, Louisiana ranked 43rd among states in reading scores of its fourth graders and 49th among states in math scores of its eighth graders. To test the effectiveness of the instruction of voucher students in private schools by comparing the students’ learning outcomes with those of similar students in below-average public schools in Louisiana is not a high bar.
Ben Greenfield is head coach of the Superhuman Coach Network, and an author, speaker and consultant. His blog is at http:// and he can be hired for coaching at http://.
His credentials include:
Bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology
Personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA)
Sports nutrition certification from the International Society of Sports Nutrition (ISSN)
Advanced bicycle fitting certification from Serotta, the “Harvard” of bicycle fitting schools
Over 10 years experience in coaching professional, collegiate, and recreational athletes from all sports
Ben hosts the highly popular fitness, nutrition and wellness website at http://, which features blogs, podcasts, and product reviews from Ben. He is a frequent contributor to Triathlete magazine and LAVA magazine, Endurance Planet (http://), the outdoor sports magazine OutThere Monthly and has been featured in WebMD, the Spokesman-Review, Inlander magazine, In-Health magazine, Fit-Pro magazine, PTontheNet, Prevention magazine, Women’s Running magazine, and Inside Triathlon magazine.
As a public speaker on fitness, nutrition, and training, Ben hosts one of the top ranked fitness podcasts in iTunes, the Get-Fit Guy (http://), and has been a keynote lecturer at the Hawaii Ironman World Championships Medical Conference, the Coeur D’ Alene Ironman Medical Conference, USAT Art & Science of Coaching Symposium, Can-Fit-Pro Conference, Pilgrim’s Wellness Center Education Series, Fleet Feet Sports Endurance Sports Clinic and REI Nutrition Clinic. He sits on the board of directors for Tri-Fusion triathlon team, the Fellowship of Christian Athletes, and is the official coach for the YoungTri. As a triathlon coach and competitor, Ben competes at Ironman and Half-Ironman World Championships, holds a ranking as of USAT’s top ranked age grouper triathletes, and competes in 15-20 triathlons each year, both nationally and internationally.