On the 100th episode of Hash Church, I mentioned 2 small research studies that show exercise can increase serum THC levels in regular cannabis users (1, 2).
Discussion starts at 40:36 in video below.
Δ9-tetrahydrocannabinol (THC) is the major psychoactive compound in Cannabis.
THC is fat soluble, rapidly absorbed and stored in the fat deposits of the body.
THC has been detected in rat fat tissue for up to 2 weeks after a single 4 mg/kg injection, and THC has been shown to accumulate in the fat tissue with repeated administration (3).
Similarly in humans, THC was observed in fat biopsies up to 28 days following the final exposure to the compound (4). The long-term storage of THC in fat is consistent with the observation that heavy cannabis users continue to give positive urine samples (>20 ng·mL−1) after 77 days of abstinence (5).
Activities that promote the breakdown of fat (lipolysis) such as exercise and dietary fasting, have been proposed to release THC stored in fat.
Stress and weight loss are also reliable promoters of lipolysis.
There have been anecdotal forensic reports of very high levels of THC in post-mortem blood samples of victims of traumatic death such as drowning (6). There have also been anecdotal forensic reports of high THC levels in the blood of ex-cannabis users who have lost significant body weight immediately prior to test sampling (7), which is thought to be due to the activation of the sympathetic nervous system (7).
Activation of the sympathetic nervous system increases the release of hormones such as adrenaline and adrenocorticotrophic hormone (ACTH), which can stimulate hormone-sensitive lipases (enzymes) to break down fats (triglycerides) into free fatty acids and glycerol (7).
Gunasekaran and colleagues (2009) demonstrated that exposing rats and their fat cells to the stress hormone ACTH, along with 24 h food deprivation both enhanced the levels of THC and its metabolite THC-COOH in animals that had been pre-exposed to THC injections (7).
The results demonstrate that conditions that promote fat breakdown (including stress) may enhance the release of THC from fat cells (adipocytes) and increase serum levels of THC.
What about exercise?
Exercise has been shown to cause a small increase in serum THC levels in regular cannabis users in 2 small human studies (1, 2).
Fourteen regular cannabis users (13 males, 1 female, age 19-40) completed 35 min of exercise on a stationary bicycle in either a fed or overnight fasted state. Plasma cannabinoid levels were assessed prior to exercise, immediately post-exercise and 2h post-exercise (1).
Exercise induced a small, statistically significant increase in plasma THC levels accompanied by increased plasma free fatty acids and glycerol levels.
With both fasted and non-fasted cohorts merged, plasma THC was significantly elevated from the pre-exercise (3.7 ± 1.1 ng/mL) to the immediate post-exercise time point (4.34 ng/mL; p < 0.001). This elevation was no longer present 2 h post-exercise (1).
Fasting induced a significant increase in plasma FFA levels, and a lowering of blood glucose, but did not significantly alter plasma cannabinoid levels (1).
Overall, these results suggest that exercise may elevate blood THC levels by releasing dormant THC from fat stores.
In another study with 6 regular cannabis users, 45 min of running on treadmill (medium intensity) caused a ~25% increase in serum THC (2).
The study took place in a drug detoxification ward parallel to study participants receiving treatment. Six chronic, daily cannabis users (one female, five males, average age 30.0 years) were exposed to a 45-min. moderate-intensity workout and a 24-hr period of food deprivation. Serum samples were drawn prior to and after interventions and analysed for THC and THCCOOH.
Note: this is the study I mentioned on Hash Church where the results are hidden in the discussion (i.e. the abstract and actual result section claim there is no difference with exercise, however, the authors include a different interpretation of results in the discussion).
"In serum, we measured transient and generally minor increases in serum THC and THCCOOH levels during physical exercise and food deprivation. Compared with individual pre-challenge values, serum THC and THCCOOH levels increased by a mean of 25% and 7%, respectively, after exercise. In a single individual (B), the increments were major in the sense that serum levels increased by a factor close to 2. The corresponding changes in serum levels after fasting were somewhat lower, but otherwise similar" (2).
The study concludes that the rise in serum cannabinoid levels during fasting or exercise is probably modest.
THC is fat soluble and stored in the fat deposits of the body.
Activities that break down fat, including exercise may increase serum levels of THC in cannabis users.
These data suggest the interpretation of blood THC levels in roadside and workplace tests might be complicated by recent exercise.
In my next post, I will discuss how exercise can boost our endocannabinoid system- the ancient system in our body that the plant cannabis interacts with.
Our body makes a compound similar to THC called anandamide, which is Sanskrit for "bliss" or "delight."
Anandamide plays a role in regulating our mood, emotions, memory, appetite and pain.
Studies have shown that exercise can boost our natural levels of anandamide and may contribute to the "runner's high."