Prior research has documented the stimulating effect of marijuana smoke on ROS production

They discretely contacted the study coordinator and arranged a time to report to the lab.Since both smokers and non-smokers were included in this study, confidentiality regarding subjects’ use of marijuana, which is currently illegal in the state of Tennessee, was not a concern. Health history, medication, and dietary supplement usage, and physical activity questionnaires were completed by all subjects.Both smokers and non-smokers were highly active and engaged in regular exercise,totaling several hours per week .Subjects were accepted as a marijuana smoker if they had smoked marijuana at least one time per week for the previous three consecutive months. Analysis indicated that smokers used marijuana frequently during the week , although we were unable to verify this or to determine the potency of the plant. Women reported to the lab for their assessment during the first three days of their menstrual cycle, as hormonal fluctuations can influence the desiredout come measures.

Prior to participation, each subject was informed of all procedures, potential risks, and benefits associated with the study through verbal and/or written form in accordance with the procedures approved by the University Institutional Review Board for Human Subjects Research . Subjects provided written informed consent prior to being admitted to participate, by using their unique subject ID number. Subject identity related to their health history and all data was maintained on a password protected computer. Subjects were compensated$20 for their participation, payable in cash at the conclusion of their lab session, within a private office. Participants reported to the lab a single time in the morning hours following a12-hour overnight fast . Participants also refrained from smoking marijuana during the 12 hours prior to the test visit. During this visit,they completed the informed consent form, health history, and physical activity questionnaires. Subjects’ heart rate and blood pressure, height, weight, waist and hip circumference were measured. A blood sample was drawn, the sample processed in a refrigerated centrifuge, and plasma obtained and stored in multiple aliquots at -70 degrees Celsius until analyzed.

We evaluated blood oxidative stress and cardio-metabolic parameters in young,physically active marijuana smokers. In those who regularly smoke marijuana abut who also engage in frequent, moderate volume exercise, there is no elevation in either lipid peroxidation or protein oxidation as compared to non-smokers,nor is there any negative impact on cholesterol, triglycerides, glucose, or blood pressure. These data are specific to a sample of men and women who smoke marijuana an average of 4.5 ± 2.3 sessions per week for at least the three month period prior to participating in the study.Endothelial cells exposed to marijuana smoke in vitro exhibited increased ROS production with reduced levels of the intracellular antioxidant glutathione. Overwhelming of the intracellular oxidant buffering system appears to result from rampant mitochondrial ROS formation.These experiments were followed up in vivo by exposing rats to marijuana smoke and staining lung tissue. Rats exposed to marijuana smoke displayed adiminished mitochondrial membrane potential and decreased ATP levels .

Previous data indicates mitochondria with reduced respiratory chain activity and subsequent membrane potential are associated with increased ROS formation though this seems to be the exception rather than the rule, as increased mitochondrial membrane potential is more often associated with increased ROS production.Interestingly, micromolar concentrations of cannabinoids inhibit activity of respiratory chain complexes II, III, and IV . It is important to note, more recent molecular work examines the effects of isolated cannabinoids rather than marijuana smoke as a whole. Additionally, computational modeling suggests THC and CBD may have the potential to act as a free radical scavenger . More importantly,cannabinoid receptors can be found either on the plasma or mitochondrial membranes. That said, molecular mechanisms and effects depend not only on the cannabinoid concentration but also the metabolic state of the cell and method used to induce oxidative stress though this still represents only afraction of marijuana smoke.In addition to the above, chronic exercise training has been show to increase antioxidant enzyme activity, which could help to offset any rise in ROS production. As mentioned previously, cigarette smoke is a similar stimulus for producing ROS. In fact, exercised mice exposed to cigarette smoke experienced reduced oxidative damage to lipids and proteins compared to sedentary smoke-exposed counterparts. Alternatively, postprandial oxidative stress is exacerbated in cigarette smokers. In terms of lipid peroxidation, exercise appears to be an effective counter measure for postprandial oxidative stress incigarette smokers .