A constituent of chocolate that has been suggested as a possible cause of
'chocoholism' (addiction to chocolate) is also being touted as a possible
cause of the feelings of euphoria ("runner's high") experienced by many
runners.It would be interesting if the same chemical--phenylethylamine--did turn out to be responsible for encouraging both running (which is associated with low body weight and high physical fitness) and bingeing on chocolate (which is more likely to be associated with obesity and sedentary lifestyle than with fitness). Source: http://news.bbc.co.uk/hi/english/health/newsid_1565000/1565230.stm Complete transcript is below my signature block Chris Forbes-Ewan Task Coordinator, Nutrition Defence Nutrition Research Centre 76 George St SCOTTSDALE Tas 7260 AUSTRALIA Phone: Int + 61 3 6352 6607 (03 6352 6607 in Australia) Fax: Int + 61 3 6352 3044 (03 6352 3044 in Australia) E-mail: [EMAIL PROTECTED] The opinions expressed in this message are those of the author and should not be taken to represent the official position of the Defence Science and Technology Organisation or of the Australian Department of Defence >From BBC Science/Tech - online (27 Sep 01): Scientists may have identified a chemical which could explain why exercise is an anti-depressant. Until now, it has not been clear why exercise has that effect. But, doctors from Nottingham Trent University suggest the chemical phenylethylamine could play a part. Phenylethylamine is a naturally produced chemical that has been linked to the regulation of physical energy, mood and attention. An enzyme changes the chemical into phenylacetic acid. There is evidence that levels of both substances are low in the biological fluids of depressed patients. In what are thought to be the first attempts to test the effects of exercise on levels of the chemical, the researchers found, overall, levels of the acid increased by 77% after exercise. Exercise Twenty healthy men, with an average age of 22 were tested. All regularly did around four hours of moderate to hard aerobic and anaerobic exercise each week. Before the study began, they refrained from exercise for a day, and a urine test was done to check for levels of phenylacetic acid, the most accurate measurement of the chemical. The next, the men exercised on a treadmill at 70% of their maximum heart rate capacity for 30 minutes. Doctors chose that level because mood changes are commonly reported at that level. The men were also asked to rate how hard they had found the exercise. When urine levels were checked, it was found phenylacetic acid levels were increased in 18 out of the 20 participants. Though the average increase in levels was 77%, the increases in individuals ranged from 14 to 572%. But the highest rises were seen in two out of the three who had rated the exercise as hard. Research possibilities The research team say though there may be many factors involved in the phenylacetic acid response, because its chemical structure is very similar to that of amphetamines, it may be that this chemical is part of a "runner's high", a phenomenon linked to natural endorphin activity in the brain. They suggest phenylacetic acid could also be important because it can cross from the blood to the brain, something endorphins cannot do. Dr Ellen Billet, who was one of the team of researchers from Nottingham Trent who carried out the research, told BBC News Online: "We felt there may be an effect of exercise on phenylethylamine." GPs can prescribe a drug based on the chemical which is known to have beneficial effects on patients. Dr Billet said: "We also know that moderate exercise has these beneficial effects. "So we wondered 'what if this was how exercise works'". She said more research needed to be done to develop their initial finding, including why different people's phenylethylamine levels are affected in different ways by exercise and if different kinds of exercise have the same effects. But she said people should still exercise, because of its benefits on both mental and physical health. "This could be used as and adjunct." A spokeswoman for the mental health charity Mind said: "Physical exercise has a valid place in the treatment and prevention of some mental health problems. "In a recent Mind survey of Cannons gym users, 75 % said they exercised to reduce their stress levels and 67% said they used exercise to maintain their mental health, like lifting 'low' moods. "Mind is calling for all GPs to offer exercise sessions on prescription to patients with mental health problems, particularly as we know that most people with mental health problems don't know this non-drug 'treatment' option exists." The research was published in the British Journal of Sports Medicine. -------- View all messages at http://sportsci.org/forum. Click on the links to JOIN, UNJOIN, alter MAIL OPTIONS, or get INFO/HELP on acceptable messages.
