between 0.5 and 1 ppm. In general, eye irritation, the most sensitive endpoint, is associated with airborne concentrations beginning in the range of 0.3 to 0.5 ppm. Eye irritation does not become significant until about 1 ppm, and rapidly subsides. Moderate to severe eye, nose and throat irritation occurs at 2 to 3 ppm. Sensory irritation has also been reported at lower levels, but is then difficult to distinguish from background. Most studies show no effect on lung function in either asthmatics or non-asthmatics. Formaldehyde causes skin irritation and has corrosive properties when ingested. In some sensitized individuals, contact dermatitis may occur at challenge concentrations as low as 30 ppm. Formaldehyde as a gas is highly reactive and is absorbed quickly at the point of contact. It is rapidly metabolised and is also produced by endogenous metabolism. Exposure to high concentrations (up to 15 ppm in rats) does not result in increased blood concentrations. Repeated formaldehyde
It's a comprehensive manual on how to hold your breath, dive deeper, and swim underwater longer. The book includes illustrations of underwater exercises, nning techniques, and selected yoga postures to enhance lung capacity. PowerLung Sport (www.fourhourbody.com/powerlung) This hand-held air-restricting device improves breathing endurance and is popular among not only swimmers but also long-distance runners, high- altitude climbers, singers, and even asthmatics. It's great for travel, and for training around injuries. Static Apnea Training Tables (www.fourhourbody.com/apnea) Customizable tables used by aspiring freedivers to safely practice apnea when out of the water. The Lung Vacuuming Technique (www.ftrain.com/lungvacuuming.html) This 20-second lung reboot is used by opera singers to regulate breathing. Useful for both sports training and minimizing stage fright. End of Chapter Notes 5
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