Endorphins article (OT alittle)

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Endorphins: Weight trainers miss out on the " runner's high "

When you cycle, swim, run, or carry out any other form of strenuous

endurance exercise, your pituitary gland releases substantial

quantities of 'endorphins', chemicals which can block sensations of

pain and produce overall feelings of euphoria. Endorphins are known

to attach to 'receptors' on the outer surfaces of brain cells, acting

like chemical keys which fit into locks. If enough endorphin is

inserted into the outer 'keyhole' of a nerve cell, that cell is

unlikely to convey pain messages to the conscious part of the brain.

Endorphins were discovered almost by accident in the 1970s when

scientists were carrying out research on drug addiction.

Investigators had wondered for years why the human brain contained

receptors for chemicals produced by the poppy plant, and they

eventually discovered why: the brain produces its own set of

neurochemicals which are actually far more potent than morphine,

opium, and heroin but share the same neural receptors with these

drugs.

The naturally produced brain chemicals, called the endorphins and

enkephalins, are released in times of stress. They can make a mangled

accident victim as serene as a Buddhist monk, and they can also make

an athlete feel great after an extremely vigorous workout. The latter

effect is sometimes referred to as the 'runner's high', and the post-

exercise surge in endorphins helps to explain why many exercisers

seem to become addicted to their sport. Their workouts become 'fixes'

which mask the pain of everyday living, and even injuries or

illnesses can't stop the training process because the athlete is

relentlessly searching for endorphin-induced mood elevations.

It's been clear for quite a while that strenuous running, cycling,

and swimming can stimulate the release of extra endorphin, but the

effects of other activities have been uncertain. Recently,

researchers from the Department of Health and Sports Science at the

University of Richmond in the United States tried to determine

whether weightlifting can also heighten endorphin levels.

In the Richmond research, six resistance-trained athletes completed

three sets of eight repetitions of isotonic strength training. All

exercises were performed at 80% of maximal effort, and blood levels

of endorphins were checked before and after the weightlifting.

The results indicated that blood-endorphin levels were not different

after weightlifting than before, although there was considerable

variability between athletes. The investigation supports previous

research which found no significant increases in endorphins following

resistance exercise, but a word of caution is in order. Compared to

an hour of intense cycling, 24 repetitions of resistance exercise

represents fairly meagre exertion, and the response might have been

far different if the weight trainers had lifted vigorously for a

longer period of time or had carried out rigorous circuit training.

However, since the Richmond team found no link between resistance

training and boosts in endorphins, we'll have to keep referring to

post-workout pleasure as the runner's high, not the strength-

trainer's delight.

'Plasma Beta-Endorphin Immunoreactivity-Response to Resistance

Exercise.' Journal of Sports Sciences, vol. 11(6), pp. 499-502,

December 1993

http://www.pponline.co.uk/encyc/0430.htm