marijuana and training...............

vdawg said:

smoking 2 packs of cigarettes a day will make you lose lung capacity. a bong rip or two a day will not.

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Smoked Marijuana as a Cause of Lung Injury.
D.P. Tashkin.
In many societies, marijuana is the second most com-
monly smoked substance after tobacco. While ∆9-tetrahy-
drocannabinol (THC) is unique to marijuana and nicotine
to tobacco, the smoke of marijuana, like that of tobacco,
consists of a toxic mixture of gases and particulates, many
of which are known to be harmful to the lung. Although far
fewer marijuana than tobacco cigarettes are generally
smoked on a daily basis, the pulmonary consequences of
marijuana smoking may be magnified by the greater depo-
sition of smoke particulates in the lung due to the differing
manner in which marijuana is smoked. Whereas THC
causes modest short-term bronchodilation, regular mari-
juana smoking produces a number of long-term pul-
monary consequences, including chronic cough and spu-
tum, histopathologic evidence of widespread airway in-
flammation and injury and immunohistochemical evidence
of dysregulated growth of respiratory epithelial cells, that
may be precursors to lung cancer. The THC in marijuana
could contribute to some of these injurious changes
through its ability to augment oxidative stress, cause mito-
chondrial dysfunction, and inhibit apoptosis. On the other
hand, physiologic, clinical or epidemiologic evidence that
marijuana smoking may lead to chronic obstructive pul-
monary disease or respiratory cancer is limited and incon-
sistent. Habitual use of marijuana is also associated with
abnormalities in the structure and function of alveolar
macrophages, including impairment in microbial phagocy-
tosis and killing that is associated with defective production
of immunostimulatory cytokines and nitric oxide, thereby
potentially predisposing to pulmonary infection. In view of
the growing interest in medicinal marijuana, further epi-
demiologic studies are needed to clarify the true risks of
regular marijuana smoking on respiratory health.
Monaldi Arch Chest Dis 2005; 63: 2, 93-100.

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The American Journal of Medicine Volume 80, Issue 4, April 1986, Pages 601?606
Marijuana smoking as cause of reduction in single-breath carbon monoxide diffusing capacity
Dan S. Tilles, M.D.1, Paul D. Goldenheim, M.D., Douglas C. Johnson, M.D.2
To investigate the effects of chronic marijuanasmoking on lung function, pulmonary function tests including single-breath carbon monoxide diffusing capacities were performed in 15 healthy women who smoked 1.7 ? 1.4 (mean ? SD) marijuana cigarettes per day for 235 ? 135 days per year for a mean of 10.5 ?3.7 years. Control groups included 27 nonsmoking and 26 tobacco-smoking women. Results revealed that marijuanasmoking with or without tobacco is associated with a reduction in the single-breath carbon monoxide diffusing capacity to 74 ?20 percent of predicted, which was significantly different from that in the nonsmoking control subjects (92 ? 11 percent; p <0.05). The subset of subjects who smoked marijuana and tobacco had a further reduction of the single-breath carbon monoxide diffusing capacity to 65 ? 17 percent, which was significantly different from that in both nonsmoking and smoking control subjects (80 ?7 percent). These results suggest that heavy marijuanasmoking when added to tobacco smoking may damage the gas exchange surface of the lung.

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Respiratory symptoms and lung function in habitual heavy smokers of marijuana alone, smokers of marijuana and tobacco, smokers of tobacco alone, and nonsmokers.
Tashkin DP, Coulson AH, Clark VA, Simmons M, Bourque LB, Duann S, Spivey GH, Gong H
The American Review of Respiratory Disease [1987, 135(1):209-16]
To evaluate the possible pulmonary effects of habitual marijuana smoking with and without tobacco, we administered a detailed respiratory and drug use questionnaire and/or lung function tests to young, habitual, heavy smokers of marijuana alone (n = 144) or with tobacco (n = 135) and control subjects of similar age who smoked tobacco alone (n = 70) or were nonsmokers (n = 97). Mean amounts of marijuana and/or tobacco smoked were 49 to 57 joint-years marijuana (average daily number of joints times number of years smoked) and 16 to 22 pack-years of tobacco. Among the smokers of marijuana and/or tobacco, prevalence of chronic cough (18 to 24%), sputum production (20 to 26%), wheeze (25 to 37%) and greater than 1 prolonged acute bronchitic episode during the previous 3 yr (10 to 14%) was significantly higher than in the nonsmokers (p less than 0.05, chi square). No difference in prevalence of chronic cough, sputum production, or wheeze was noted between the marijuana and tobacco smokers, nor were there additive effects of marijuana and tobacco on symptom prevalence. We noted significant worsening effects of marijuana but not to tobacco on specific airway conductance and airway resistance (tests of mainly large airways function) in men and of tobacco but not of marijuana on carbon monoxide diffusing capacity and on closing volume, closing capacity, and the slope of Phase III of the single-breath nitrogen washout curve (tests reflecting mainly small airways function) (p less than 0.03, two-way ANCOVA). No adverse interactive effects of marijuana and tobacco on lung function were found.

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