Access to this full-text is provided by Springer Nature.
Content available from Sports Medicine
This content is subject to copyright. Terms and conditions apply.
Vol.:(0123456789)
Sports Medicine (2021) 51 (Suppl 1):S75–S87
https://doi.org/10.1007/s40279-021-01505-x
REVIEW ARTICLE
Cannabis andAthletic Performance
JamieF.Burr1 · ChristianP.Cheung1· AndreasM.Kasper2· ScottH.Gillham2· GraemeL.Close2
Accepted: 16 June 2021 / Published online: 13 September 2021
© The Author(s) 2021
Abstract
Cannabis is widely used for both recreational and medicinal purposes on a global scale. There is accumulating interest in the
use of cannabis and its constituents for athletic recovery, and in some instances, performance. Amidst speculation of potential
beneficial applications, the effects of cannabis and its two most abundant constituents, delta-9-tetrahydrocannabinol (THC)
and cannabidiol (CBD), remain largely un-investigated. The purpose of this review is to critically evaluate the literature
describing the effects of whole cannabis, THC, and CBD, on athletic performance and recovery. While investigations of whole
cannabis and THC have generally shown either null or detrimental effects on exercise performance in strength and aerobic-
type activities, studies of sufficient rigor and validity to conclusively declare ergogenic or ergolytic potential in athletes are
lacking. The ability of cannabis and THC to perturb cardiovascular homeostasis warrants further investigation regarding
mechanisms by which performance may be affected across different exercise modalities and energetic demands. In contrast
to cannabis and THC, CBD has largely been scrutinized for its potential to aid in recovery. The beneficial effects of CBD
on sleep quality, pain, and mild traumatic brain injury may be of particular interest to certain athletes. However, research in
each of these respective areas has yet to be thoroughly investigated in athletic populations. Elucidating the effects of whole
cannabis, THC, and CBD is pertinent for both researchers and practitioners given the widespread use of these products, and
their potential to interact with athletes’ performance and recovery.
* Jamie F. Burr
burrj@uoguelph.ca
1 Human Health andNutritional Sciences, University
ofGuelph, 50 Stone Road E, Guelph, ONN1G2W1, Canada
2 Research Institute forSport andExercise Sciences, Liverpool
John Moores University, Liverpool, UK
Key Points
Use of cannabis, THC, and CBD by athletes for the
purposes of improving performance and recovery is
increasingly reported across different sports and levels of
competition
Appropriate empirical evidence regarding the effects of
cannabis use on sport performance is lacking. Under-
standing the short- and long-term effects of cannabis
and THC on human performance in athletes will require
well-controlled, athlete-specific research, with applied
performance outcomes
CBD may have some promise for aiding athletes with
recovery by improving sleep quality, pain, and mild
traumatic brain injury
1 Introduction
The empirical case for or against cannabis use to aid ath-
letic performance remains tenuous. Despite evidence of
long-standing human consumption over the ages [1], sci-
entific investigation into the effects of cannabis has been
relatively limited, largely in part to challenges faced to
investigate a drug that has a long global history of pro-
hibition and tight regulatory control [2, 3]. Despite can-
nabis remaining an illicit drug in a majority of countries
and holding a place on the World Anti-Doping Agency’s
(WADA) prohibited substance list, accounts of its use
amongst competitive and recreational athletes abound
[4–7].
Today, the global use of cannabis and formulations
made of its derivatives are progressively more widespread
as many nations relax laws around both medical and rec-
reational use. Cannabis has been noted as the second most
consumed recreational substance, next to alcohol [8], and
with such ubiquity and increasing belief of potential for
health benefit, the enticement for uptake and use by ath-
letes is not surprising. While commonly used as a recrea-
tional drug outside the context of sport, evidence suggests
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S76 J.F.Burr et al.
that athletes who use cannabis do so with the intent of
enhancing performance (whether this is likely to occur or
not), with factors such as sporting background, individual
vs. team sport participation, competition level, sex, and
demographic background further affecting predispositions
to use [4–6]. A recent meta-analysis of 11 studies repre-
senting over 46,000 athletes of varying age and ability
suggests that ~ 23% have used some form of cannabis in
the past year [9].
Plants of the Cannabis genus contain over 100 genus-
specific molecules [10], known as phytocannabinoids:
the two most studied being delta-9-tetrahydrocannabinol
(THC) and cannabidiol (CBD). THC is widely recognized
for its psychotropic effects. The selective breeding and cul-
tivation of new cannabis strains for both recreational and
medicinal use has commonly focused on THC, resulting in
alterations to cannabinoid ratios and increases in relative
THC concentration over time [11]. It is now understood
that THC exerts a variety of physiological effects via the
endogenous cannabinoid, or endocannabinoid, system.
More specifically, THC acts as a partial agonist to the
putative endogenous cannabinoid receptors type 1 (CB1)
and 2 (CB2), which are located in a wide range of central
and peripheral tissues [12, 13]. CBD, on the other hand, is
devoid of psychotropic effects [11], and while it appears to
have limited physiological influence through CB1 or CB2,
it is believed to act at a number of other receptor targets
and may modulate the effects of THC [13–15]. Given the
unique effects of THC and CBD to elicit differing physi-
ological effects that could alter exercise performance or
recovery, coupled with their differing status as legal or
prohibited substances, there is a growing interest in scien-
tific evidence for a variety of purported uses. Furthermore,
exercise itself may have unique interactions with the endo-
cannabinoid system which may modulate the effects of
exogenous cannabinoids [16]. It is important to acknowl-
edge that cannabis contains many other molecules which
could theoretically have physiological effects, and conse-
quently affect human performance; however, the effects
of these less abundant cannabinoids and compounds are
beyond the scope of this review.
Cannabis is most commonly consumed via inhalation of
combusted plant material, colloquially referred to as smok-
ing, which leads to rapid uptake and effects [17]. Cannabi-
noids may also be consumed by ingesting cannabinoid-con-
taining food products, leading to delayed uptake (30–60min
post) with peak effects occurring between 1.5 and 3h post-
consumption [18]. It should, however, be acknowledged
that the pharmacology of THC and CBD may vary signifi-
cantly according to a variety of contextual factors, leading
to a wide range of bioavailability and elimination rates, as
reviewed elsewhere [19]. It is suggested that the effects
of consumption, specifically the anxiolytic properties and
muscle relaxing effects [4] are a highly sought-after effect
for many athletes. Isolated CBD may also possess anxiolytic
effects and is purported to have a variety of other beneficial
effects such as improvements to sleep, exercise recovery,
pain, anxiety, mood, and recovery from concussion [20].
These factors represent motivation for use amongst athletic
populations, including professional athletes [20]. Despite the
reported widespread use of whole cannabis, cannabinoid-
based food products, and isolated CBD amongst athletes
who have intentions of affecting athletic performance and/or
recovery, there is no clear consensus about the general effi-
cacy of use. At present, according to WADA, cannabis is in
contravention of at least two of the three tenets of acceptable
use in that it: has potential to enhance sport performance,
represents a health risk to athletes, and violates the spirit of
sport. Consequently, cannabis and all other cannabinoids
(with the exception of CBD) are prohibited during the in-
competition phase. Amidst the current evidence this remains
a controversial topic in the anti-doping realm [21].
While opinions regarding the efficacy of cannabis (and
its constituent products) to meaningfully affect sport perfor-
mance remain split, cannabis demonstrates clear potential
to perturb cardiovascular [22], respiratory [23], and cogni-
tive function [24]. However, in an era of evidence-based
decision making, a paucity of trials explicitly examining the
effects of whole cannabis, THC and CBD on varied exercise
performance and recovery specific outcomes leaves a sig-
nificant vacuum in which decisions must be made. Notably,
rulings about the suitability of use in the context of sport
must simultaneously consider both the potential to alter per-
formance and the potential for adverse health effects, which
may include serious cardiovascular events, amongst other
dangers, which are discussed in detail elsewhere [25–28].
Amongst these issues are the effects that THC may have
on alterations in motor control or decision making [29] but
in many ways these factors are limited to the psychologi-
cal, as opposed to psycho-physiological, effects on perfor-
mance. Thus, this review focuses on the existing evidence
for the physiological effects of cannabis, THC, and CBD
consumption for exercise performance and recovery, while
highlighting requisite areas of future research to progress our
empirical understanding in the context of sport performance.
Given the notable differences in the psychological and physi-
ological effects of THC and CBD, as well as the potential
indications for use in the context of sport, CBD is discussed
independently of whole cannabis and THC.
2 Cannabis, THC, andExercise Performance
The topic of cannabis use and the specific effects of THC
on human exercise performance have been considered previ-
ously [9, 21, 27, 30–36]. Perplexingly, despite there being
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S77
Cannabis and Athletic Performance
few new data generated over the past few decades, repeated
interpretations of these data have led to vastly different
conclusions, with reviews presuming: no benefit [30, 31],
potential advantages [21] and predominantly an ergolytic
effect [9, 32–34]. As such, we include a critical review of
current work, and recognition of the knowledge gaps that
must be filled to clarify the effect on human performance
more specifically.
Compared to the empirical data on other performance
related drugs and supplements, the evidence regarding can-
nabis and THC use is conspicuously lacking. While the vol-
ume of data is evidently sparse, it is also noteworthy that the
most relevant literature was published 35–45years ago, with
little progress since. Further, there are important considera-
tions of study design and collection methods that limit our
ability to meaningfully extrapolate findings for understand-
ing the potential effect of cannabis and THC use on sport-
ing performance in the current day. Amongst these factors
are: a substantial increase in the typical dose of THC over
time (increased between sixfold and tenfold [11]), evolv-
ing methods of consumption and recognition that timing of
intake/uptake may influence physiological responses, and an
improvement in our ability to quantify performance as physi-
cal work output. At the time of writing, we have identified
ten studies that consider the effects of cannabis on human
performance. Four are cross-sectional studies that charac-
terize the physical capacities of long-term cannabis users
compared to non-using controls [37–40], and six involve the
administration of cannabis or THC to participants prior to
exercise [41–46]. Of these experimental studies, 50% were
performed in persons with identified coronary artery disease
or chronic obstructive pulmonary disease (COPD).
2.1 Chronic Cannabis Users
Even at a superficial level, there is value in understand-
ing whether individuals who habitually use cannabis dif-
fer in their ability to perform exercise from those who do
not. Such investigations can shed light on the possibility
of persistent performance effects of cannabis with long-
term use. However, while such research designs eliminate
the need for logistically challenging studies that require the
longitudinal administration of dosed cannabis, their cross-
sectional nature precludes the control of potential bias and
cause-and-effect cannot be concluded. Of the existing data
comparing cannabis users to non-users, there are no reported
differences in aerobic fitness (VO2max), blood pressure, mus-
cular strength and endurance measures, work capacity, and
perceived exertion [37–40]. In physically active cannabis
users, there are no differences in anaerobic power, or mark-
ers of stress and inflammation [37, 39]. Notably, in all stud-
ies, participants had been asked to abstain from cannabis
consumption for hours to days prior to testing in an attempt
to avoid transient physiological effects from recent use, but
this might not represent a normal functioning state for heavy
users and may be confounded by potential interactions with
withdrawal effects [47], which should also be considered
in studies where cannabis is administered. The typical con-
cern about the potential for bias (e.g., self-selection to par-
ticipate) in cross-sectional studies must still be considered.
Taken together, there is presently little evidence to suggest
chronic cannabis use performed in isolation from training or
competition exerts a great effect on any measure of physical
performance in recreationally active participants.
2.2 Diseased
Exercise is a commonly used tool for the identification and
elicitation of signs and symptoms of underlying cardiovas-
cular disease (CVD). While studies examining the com-
bined cardiovascular stress of exercise with cannabis use
in persons with identified CVD offer select insight into the
human ability to perform aerobic work, their widespread
acceptance as concrete evidence of the effects of cannabis or
THC on general or high-level human performance is likely
misplaced. It is worth highlighting that these studies were
never designed to specifically address these questions, and
this fact appears to be commonly overlooked in the context
of interpretation and application for sport.
The first study of cannabis and exercise was performed
in patients (n = 10) with significant coronary artery dis-
ease (> 75% narrowing of coronary artery), with the onset
of angina as a major endpoint [42]. Comparing exercise
capacity after smoking cannabis or a cigarette placebo, both
groups demonstrate a decrease in time to exhaustion. This
effect was greater with cannabis use (48% vs 8.6%), pos-
sibly because of an increase in myocardial oxygen demand
(rate-pressure product), a mechanism discussed in Sect.3.
It is worth noting that, according to the loading protocol
described in the methods, even during the control condi-
tion participants were capable of only a 25W power output
and ≤ 25% of the test was performed at an increased work-
load of 50W. For comparison, the modern professional male
cyclist can sustain approximately 500W for a similar dura-
tion of 120s amidst hours of riding on consecutive days
[48], highlighting the absurdity of using one population to
predict effects in the other. The use of cannabis was also
a novel stimulus amongst these participants. This work
was confirmed by the same group using similarly diseased
patients, and an equally low exercise stimulus and THC
dosage (< 15mg) the following year [45]. It is worth high-
lighting that these two studies commonly represent > 50%
of the “performance” evidence cited in existing reviews
to suggest an ergolytic effect of cannabis on performance.
More recently, to explore the effects on breathlessness and
exercise capacity, COPD patients consumed whole cannabis
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S78 J.F.Burr et al.
(vaporized not smoked, 6.4mg THC) prior to cardiopulmo-
nary exercise testing [46]. Cannabis was reported to have
no impact on any cardiorespiratory responses, nor exercise
time, and it is worth noting that exercise lasted < 5min.
Importantly, this group of patients had advanced COPD
and fitness that was approximately 10% of what would be
expected for a healthy (non-athletic) control.
2.3 Healthy
Steadward and Singh published the first investigation—and
to date one of only three studies—in healthy participants
(n = 20), exploring the effects of cannabis on cardiorespi-
ratory responses to exercise, physical work capacity, and
strength [41]. After smoking a moderate dose of THC
(18.2mg), participants showed no apparent effect on hand-
grip strength, but submaximal work capacity on a cycle
ergometer decreased. Importantly, this decrease was con-
comitant with and inseparable from an increase in sub-
maximal heart rate (HR) in the cannabis group. In papers
reporting this research as evidence of an ergolytic effect of
cannabis, it is commonly ignored that the test of physical
performance, known as the PWC170—a commonly used test
from this time, is a submaximal test for which performance
is estimated based on the work output at a given HR (i.e.,
physical work capacity at a heart rate of 170bpm). While
the linear relationships between HR and either VO2 or power
output make this a useful measure of capacity under normal
circumstances [49, 50], this relationship can no longer be
trusted as accurate after the administration of a drug that
specifically alters the variable that is being controlled for. It
should be surprising to no one that when submaximal HR
is artificially inflated—and power is measured at a clamped
HR—that the work output will necessarily be lower. Nota-
bly, there are examples of other definitively ergogenic sub-
stances, such as ephedrine and caffeine, that increase sub-
maximal HR and improve endurance performance [51, 52].
Thus, it is inadvisable to conflate the tachycardic effects
of cannabis consumption with an ergolytic effect. Ava-
kian etal. [43] similarly followed-up with a submaximal
exercise study (40–50% VO2max) with individuals (n = 6),
habituated to cannabis use. While no effects of cannabis use
were evident on blood pressure, ventilation (VE) or VO2, a
sustained tachycardic HR response was reported. However,
no true measures of maximal exercise performance were
recorded and the extrapolation of a submaximal effect on
HR at 50% of capacity to exercise performance in a com-
petitive situation requires large, unsupported assumptions of
equivalency. Despite the results of this work often being ref-
erenced regarding exercise performance, the authors them-
selves conclude that “…the significance of their observation
is not established”. Interestingly, all subjects were able to
identify the placebo from the low dose (7.5mg) THC condi-
tion during exercise, leaving the possibility that psychologi-
cal factors could modify exercise behaviors, but this has yet
to be an empirically tested outcome, nor has blinding been
effectively performed. This is an important consideration for
future research examining the psycho-physiological effects
of cannabis in a more targeted performance setting.
The final, and most specific performance work to date,
is the only study to examine healthy participants exercis-
ing to maximal capacity. In this work, Renaud and Cormier
[44] had participants (n = 12) perform progressively more
challenging workloads (16.4W each min) until “leg failure”
both under control conditions and after having consumed
cannabis (1.7% THC) dosed at 7mg of dried cannabis per
kg body weight. At maximal exercise, no differences were
found in HR, VE, VO2 or volume of exhaled carbon dioxide
(VCO2); suggesting that despite the submaximal tachycardic
response, physiologic responses at maximal workloads were
not different after cannabis consumption [44]. Examina-
tion of submaximal through maximal work clearly shows a
diminishing difference between placebo and cannabis groups
as exercise intensity is increased. At workloads greater than
80% of maximal effort no differences existed, calling into
question the implications of previous submaximal work for
modelling effects of performance, especially as VO2max is
not affected [44]. The most lauded finding from the work
of Renaud and Cormier [44] was the fact that there was a
significant difference in exercise duration, with cannabis
exposure decreasing time to exhaustion. While the data do
indeed support this finding, examination of the exercise test-
ing protocol demonstrates that this difference (16.1 ± 4 vs
15.1 ± 3min) represents an average difference of a single
one-minute stage, and 100 kpm/min, or about 16W. It is
unclear if this was truly a scaled linear variable (time), or
if it was an ordinal variable—such that participants were
encouraged to finish each stage with only finished stages
being counted. In either case, the implications of such a
small magnitude change on this type of staged test are ques-
tionable. As this is truly the only investigation of exhaus-
tive performance in healthy participants, the methodological
ambiguity and debatable practical validity of the findings
indicate that further work is warranted.
2.4 Knowledge Gaps andRecommendations
There is a paucity of valid exercise studies designed to
specifically investigate the effects of cannabis and THC on
human exercise capacity and performance. It is noted that
physiological capacity and performance are interrelated, but
not equivalent. Factors such as an athlete’s perception (e.g.,
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S79
Cannabis and Athletic Performance
time, pain, appropriate pacing strategies) and motivation
ultimately affect performance and could also be altered by
cannabis or THC, but have not been investigated. Healthy
subjects who have varied levels of fitness and habituation
to cannabis need to be studied, with further consideration
of the methods of cannabis intake and the pharmacokinet-
ics that dictate the time of peak effects. Dose–response
curves should be developed, with varied exercise modes
(e.g., cycling, running, strength assessments), intensities
(i.e., submaximal, maximal, sprint-power based), durations
(e.g., up to and including ultra-endurance events) and mod-
els of performance (time to exhaustion, time trial, power
output). Improved technologies, including electronically
braked ergometers and breath-by-breath indirect calorimetry,
now allow research to move beyond the incremental-stage
graded exercise test. These contemporary technologies and
best practices should be employed to increase the sensitivity
and validity for tests of physical capacity and performance.
3 Cannabis andSystems‑Level
Cardiorespiratory Physiology
While the bona fide effects of cannabis on athletic perfor-
mance are limited by an incomplete evidence-base with low
ecological validity for athletes, the physiological actions of
cannabis and THC offer important insight into perturbations
of cardiorespiratory homeostasis through which cannabis
may interact with performance. Studies from these areas
have generally been considered separately (for reviews of
cannabis and performance see [9, 21, 27, 30–36]; for reviews
of cardiovascular effects of cannabis see [22, 25]) with no
comprehensive integration. As exercise clearly requires a
coordinated and integrated response from multiple physi-
ological systems, this is a notable shortcoming.
Studies administering cannabis and isolated THC to
healthy individuals have revealed a wide range of cardio-
vascular effects, including: changes in heart rate [41–45,
53–85], cardiac function [55, 59, 64, 75, 76, 79, 83], blood
pressure [41, 42, 53, 57, 59–61, 63–65, 75–78, 83], orthos-
tatic hypotension [53, 60, 80], ventilatory sensitivity to car-
bon dioxide [61], and limb blood flow [53, 78, 85].
Transient sinus tachycardia is a commonly reported dose-
dependent effect of cannabis and THC consumption [55,
68, 70, 72, 82, 83]. As noted for the performance literature,
this effect persists during submaximal exercise, resulting in
a greater rate-pressure product at a given exercise intensity,
indicative of increased myocardial oxygen demand [86].
When consumed via smoking, this elevated myocardial oxy-
gen demand associated with cannabis consumption could
be exacerbated by reduced oxygen supply consequent to the
inhaled carbon monoxide present in cannabis smoke [87].
The disruption of the myocardial oxygen supply/demand
relationship likely explains why myocardial ischemia is
precipitated by cannabis smoking in coronary heart disease
patients [42, 45]. It is worth noting this phenomenon may
not be unique to cannabis smoking, as placebo and tradi-
tional cigarette smoking in these same studies induced an
attenuated, but still significant, reduction in time to angina
compared to cannabis, likely due to the fact that all smoking
involves the inhalation of carbon monoxide and hydrocar-
bons but does not produce the cannabis specific tachycardic
effect.
The acute effects of cannabis and THC consumption
on blood pressure are more variable, with potential impli-
cations for perfusion during exercise. Investigators have
reported increases in systolic and diastolic pressure [41,
42, 53, 59, 61, 64, 65, 76–78, 83], reductions in blood
pressure [60, 63], or no changes in blood pressure [43,
58, 59, 62, 63, 73–75, 81, 88–90] following cannabis or
THC consumption. Unlike HR, it appears that pressure
responses during exercise are not affected following a
single instance of cannabis consumption [43]. However,
if THC is persistently administered in high doses (up to
210mg/day for multiple weeks) blood pressure responses
to exercise are altered; with an attenuation of the rise in
systolic blood pressure, and an exaggeration of the reduc-
tion in diastolic blood pressure [77]. Thus, the timing
and quantity of THC dose may also influence the pres-
sor response to exercise. The reported increase in limb
blood flow following cannabis consumption [53, 78, 85]
could also partially explain the varied effects on pressure,
but limb blood flow following cannabis and THC con-
sumption has only been examined at rest. During exercise
performance, cannabis induced increases in flow could be
relevant given limited evidence that suggests that muscle
blood flow may, to some degree, limit maximal exercise
capacity [91]. Further studies are needed to reach conclu-
sions about how these hemodynamic effects of cannabis
and THC interact with performance outcomes.
Echocardiographic studies have generated equivocal find-
ings with respect to cardiac function, reporting both reduced
systolic function [59] and increased left ventricular tissue
velocity [64, 76] following cannabis smoking. Whether the
myocardial effects of cannabis and THC impact exercise per-
formance remains unclear, owing largely to uncertainty over
whether the effects observed at rest persist during exercise—
and if so, the extent of functional consequences. Employing
modern tests of cardiac function and imaging techniques,
such as stress echocardiography [92] or magnetic resonance
imaging [93], is required to fill this knowledge gap, as imag-
ing and analysis capabilities have evolved substantially since
the publication of the aforementioned seminal works. The
importance of cardiac mechanics (such as left ventricular
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S80 J.F.Burr et al.
strain, torsion and twist) for understanding cardiac function
is increasingly recognized [94, 95]; yet to date only two stud-
ies have examined these variables in chronic cannabis users
[96, 97], and no studies have examined the acute effects of
cannabis or THC.
A large body of evidence from in-vitro and animal models
indicates that the mechanisms through which cannabis and
THC elicit cardiovascular effects are likely vast and many
could be relevant to exercise performance (for review, see
[25]). In humans the cardiovascular effects of THC and can-
nabis appear to be largely mediated through autonomic nerv-
ous mechanisms and the endocannabinoid system. Treatment
with beta-adrenergic blockade prior to THC or cannabis
administration markedly blunts tachycardic [65, 75, 84, 85]
and pressor [65, 75] responses, increases in limb blood flow
[78, 85], and alterations to systolic time intervals [75]. Thus,
it appears that the cardiovascular effects of THC and can-
nabis are mediated at least partially through the sympathetic
nervous system. Beta-adrenergic blockade in combination
with anti-cholinergic agents augments the effects of THC
and cannabis on HR and blood pressure [75, 77, 78, 85].
The endogenous cannabinoid system also appears able to
facilitate certain cardiovascular effects of THC, suggesting a
degree of redundancy. Following the discovery of the endo-
cannabinoid system and identification of CB1 in cardiovas-
cular tissues [98, 99], investigations of human participants
revealed that inhibition of CB1 also ablates the tachycardic
effects of cannabis [69, 70, 72–74, 89, 100]. Despite these
putative mechanisms through which cannabis and THC exert
cardiovascular effects, cannabis contains hundreds of chemi-
cal compounds, including over 100 phytocannabinoids [10].
Thus, it should be accepted that the physiological effects of
cannabis cannot be solely attributed to THC until further
investigations examine the many constituents of the plant.
Given the inseparable links of the cardiovascular and
respiratory systems to support aerobic exercise perfor-
mance, the effects of cannabis and THC consumption on
respiratory function must be considered. Epidemiological
analyses of the respiratory effects of chronic cannabis use
have failed to show a clear linear relationship between
cannabis smoking and reduced pulmonary function [101],
and generally only demonstrate reduced function with very
heavy cannabis use [102]. Thus, it may be that exercise
capacity is, similarly, only impacted negatively with heavy
cannabis use. Cross-sectional data comparing VO2max,
work capacity, pulmonary function, and strength and
endurance outcomes have consistently demonstrated no
differences between young cannabis users and non-users
[37–40]; however, no comparison has been made between
non-users and longtime heavy users.
The acute and transient effects of cannabis and THC on
respiratory function during exercise have received little
attention. Of the two studies performed in healthy indi-
viduals, one revealed no differences in respiratory function
[41], and the other demonstrated an increased capacity to
expire forcefully (FEV1) after exercise [44]. Alterations
in flow are most likely related to the reported broncho-
dilator effects of THC [103]. Theoretically, the ability
of THC to induce bronchodilation in healthy and asth-
matic participants [104] provides a potential mechanism
through which cannabis could influence performance, as
bronchodilating substances have previously been used
by athletes for purported ergogenic effects [105]. How-
ever, the ergogenic potential of this bronchodilator effect
remains to be confirmed, and it is notable that COPD
patients experienced no improvement in exercise capacity
or respiratory function following inhalation of vaporized
cannabis [46]. It must also be considered that a number
of bronchodilating substances are currently permitted for
use in sport by WADA [106], and the evidence support-
ing the ergogenic effects of bronchodilating substances is
tenuous [107]. Another intriguing observation is that THC
appears to alter ventilatory sensitivity to carbon dioxide
[61]. At present, it is not clear whether this effect occurs,
or is consequential, during exercise.
There currently exists a substantial body of evidence
demonstrating that consumption of cannabis leads to
numerous systemic cardiorespiratory effects at rest, largely
due to the actions of THC. Despite increasing use of rec-
reational and medicinal cannabis, it remains unclear which
effects persist during dynamic exercise, and how they
might impact performance. Understanding these effects
is not only necessary to determine how cannabis impacts
performance across athletic disciplines, but also to inform
decisions regarding the safety and regulation of cannabis
use in both athletic and non-athletic populations.
3.1 Knowledge Gaps andRecommendations
The effects of cannabis and THC on rudimentary cardi-
orespiratory physiology in resting humans are well charac-
terized; however, both cannabis potency and investigative
research capabilities have increased dramatically since many
of these studies were initially performed, without concomi-
tant study. The independent effects of inhaling combusted
plant material versus the effects of cannabis and THC are
incompletely understood, both at rest and in an exercise con-
text. For future work to successfully characterize the effects
of cannabis and THC on performance, underlying physi-
ological effects must be rigorously investigated before, dur-
ing, and after exercise.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S81
Cannabis and Athletic Performance
4 CBD andtheElite Athlete
While whole cannabis is commonly used across the globe
for both recreational and medicinal purposes [9] in many
countries it remains an illicit drug [108], and from an ath-
letic perspective it is currently prohibited (in competition)
by WADA. However, one of the major phytocannabinoids
within cannabis, CBD, was specifically removed from the
WADA prohibited list in 2018 and as a consequence its inter-
est in sport has grown exponentially. Interest in CBD is also
largely driven by the fact that the
l
-isomer of CBD originat-
ing from cannabis plants does not have psychotropic prop-
erties, although some synthetic analogs might [109]. The
use of CBD in sport has recently been reviewed extensively
[110]. The individual phytocannabinoid derivatives from the
cannabis plant face discrepant restrictions by some sporting
governing bodies and WADA [106]. Of all the phytocan-
nabinoid derivatives, the only constituent absolutely legal
from a WADA perspective is CBD. All other phytocannabi-
noid derivatives are prohibited per se except THC which is
considered a threshold substance, meaning that only con-
centrations > 150ng/ml in urine result in an anti-doping rule
violation (ADRV) [111]. It is also important to stress that
the legislative regulation of CBD itself is somewhat complex
and it is, therefore, vital that athletes are aware of the spe-
cific country, and in the case of the US, state specific legisla-
tion before considering the potential for CBD use in sport.
Despite this lack of clarity surrounding the precise legality
of CBD commerce and consumption, supplementation in
athletic populations has grown due to its purported effects
on athletic performance and recovery [9, 20].
4.1 Sleep andAnxiety
Appropriate sleep is widely accepted as an integral com-
ponent of the recovery process in athletes (for review see
[112]). Professional athletes have previously reported sub-
optimal sleep quantity [113] and quality [114]. Indeed, dis-
turbances in sleep can be a consequence of several mecha-
nisms including pre-game supplementation [115], the time
of competition [116], implications of long-haul travel [117],
and anxiety associated with competition [118–121]. It is,
therefore, understandable that athletes supplement products
such as CBD, with the aim to improve sleep efficiency and
provide anxiolytic properties [122], despite associated evi-
dence being limited to clinical research as opposed to within
elite athlete cohorts.
Any potential positive effects of CBD on sleep are pri-
marily limited to diseased populations, such as sufferers
of Parkinson’s disease [123] and post-traumatic stress dis-
orders [122], with randomized controlled trials in human
participants somewhat limited. However, Carlini & Cunha
reported that CBD supplementation (160mg) significantly
increased sleep duration in individuals reporting difficulties
in both sleep onset and quality [124]; however, conclusions
were limited to perceived/subjective measures as opposed to
objective polysomnographic data. More recent research from
Linares and colleagues showed no significant effects of CBD
(300mg) on either subjective sleep quality or objective poly-
somnography measures, though it is important to note that
although the latter utilized a higher dose of CBD, partici-
pants were healthy and not experiencing any reported sleep
disturbance [125]. As such, although CBD shows promise in
sleep quantity and quality, well-designed randomized con-
trolled studies in athletic populations are required to deter-
mine the exact, if any, situation in which CBD may provide
this sleep (and thus recovery) enhancing effect.
4.2 Pain, Inflammation, andMuscle Function
Exercise induced muscle damage (EIMD) is a well-estab-
lished phenomenon following athletic activity (for review
see [126]). Throughout congested competition schedules and
particularly damaging exercise bouts [127], pain and recov-
ery management is often modulated via non-steroidal anti-
inflammatory drugs (NSAIDs) and, in some cases, opiates
[128]. However, in addition to the adaptation blunting effect
of NSAIDs [126], chronic consumption has the potential to
induce several adverse health effects [129]. It is, therefore,
unsurprising that in a recent study of elite rugby players,
26% of players had previously experimented, or were cur-
rently using CBD supplements, which have been shown to
have mild-moderate adverse effect profiles in humans [130,
131]. That said, as a result of CBD’s metabolism by the
CYP3A4 and CYP219 enzymes it can potentially increase
drug-drug interactions with other compounds metabolized
by the same enzymes, subsequently increasing potential
adverse effects profiles [132]. In this study, ~ 80% of rugby
players cited pain management as their primary motive for
experimenting with CBD [20]. This high prevalence of use
was in spite of the current lack of an evidence-base for the
efficacy of supplementation, and risks of potential ADRVs
[20, 133]. Interestingly, despite the high number of rugby
players taking CBD for pain modulation, only 14% of rugby
players reported any beneficial effect [20]. These findings
may be as a result of the disparity in the reported doses
consumed by athletes [20], especially as higher doses may
be required to offer anti-inflammatory effect in humans. Low
vs. high doses of CBD (10 vs. 500mg/day) have shown
differing pain alleviating results (non-significant vs. signifi-
cant) in patients experiencing high levels of gastrointestinal
inflammation [134, 135], with higher dosages, although sig-
nificantly relieving pain, also resulting in issues within the
gastrointestinal tract or central nervous system. It is worth
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S82 J.F.Burr et al.
noting that the population of this study already had gastro-
intestinal issues, which may, in part, explain these increased
adverse effects [135].
Despite the widespread inclusion of strength train-
ing amongst high-level athletes, studies investigating the
effects of CBD supplementation on resistance exercise are
extremely limited. To date, only two preliminary studies
are available with varying research designs, and equivocal
findings. For example, 150mgday of oral CBD (2 × 75mg
doses given immediately post, 24 and 48h following a mus-
cle-damaging protocol) had no beneficial effects on either
muscle function or perceived soreness in untrained males
(n = 13) [136]. The only other available data on CBD and
muscle soreness in an athletic context are limited to a sin-
gle abstract from a conference communication [137]. This
study assessed muscle damage (via creatine kinase [CK])
following a single bout of resistance exercise and suggested
that CBD supplementation (60mg/day) attenuated the acute
increases in CK. However, alongside the proposed reduction
in muscle damage, there were also reductions in strength
within 24h of supplementation. It is important to consider
that neither of these studies assessed blood or urine can-
nabinoid concentrations and the equivocal data could be
related to the efficacy of the supplementation protocols
with major differences in the actual dose of CBD, number
of days supplemented, and route of administration. Collec-
tively, the evidence to date on the effects of CBD on mus-
cle function following damaging exercise could be, at best,
described as ‘in its infancy’ and, therefore, it is not possible
to reach any form of conclusion as to the efficacy of CBD
for muscle recovery. Research is now required, including
pharmacokinetic data, measures of blood cannabinoids,
and dose–response data to fully explore if CBD is able to
attenuate muscle damage and/or enhance recovery follow-
ing exercise.
4.3 Neuroprotection andTraumatic Brain Injury
Concussion is a type of mild traumatic brain injury (mTBI)
[138] which may occur following a rapid deceleration or
rotational force applied to the brain [139]. These biomechan-
ical mechanisms of injury are a particular concern in col-
lision and combat sports such as rugby union [140], rugby
league [141] American football [142, 143], as well as boxing
and mixed-martial arts [144]. Several acute side-effects may
be experienced during concussion including headaches, cog-
nitive impairments, sleep disruption, and behavioral changes
[145]. Moreover, long-term effects of concussion can
include behavioral changes leading to aggressive episodes,
anxiety, and depression [146]. Despite the exact mechanisms
by which this may be achieved being unconfirmed, CBD has
been proposed to offer a protective benefit in athletes who
are “at risk” of mTBI in sport [147]. Suggested mechanisms
include the anti-inflammatory nature of CBD [148, 149],
anandamide uptake and enzymatic hydrolysis [150], and/
or a decrease in adenosine reuptake [151]. To date, a single
murine study has investigated the effects of CBD on mTBI
[147]. In this study the authors concluded that chronic CBD
administration (equating to ~ 51mg/day when converted to a
human equivalent dose [152]) reduces dysfunctions relating
to the anxious, aggressive and depressive behaviors often
exhibited following mTBI. Given the severe consequences
of mTBI to health, coupled with the proposed neuroprotec-
tive potential of CBD, it is imperative that additional inves-
tigation in this area be completed in humans to understand
the mechanisms by which CBD may offer a neuroprotective
benefit to athletes who are at risk of mTBI.
4.4 Knowledge Gaps andRecommendations
As a consequence of the complicated legislative status of
CBD, research in-vivo is less common than for other ergo-
genic supplements regularly consumed by athletes. Whilst
many CBD products available for purchase without prescrip-
tion claim to have negligible, or even 0% THC, these claims
are sometimes unfounded with a recent study suggesting that
only 3 of a selected 25 CBD products were within ± 20% of
claims made on their respective containers [153]. Moreover,
many CBD products that are THC free still contain other
cannabinoids, which are prohibited by WADA, and detec-
tion may result in ADRVs. Indeed, as THC can be stored in
fat tissue [154], blood and urine metabolites may peak fol-
lowing specific periods of lipolysis inducing exercise [154]
or fasting [155]. When considering CBD products athletes
should also ensure that the L-isomer is the molecule con-
tained, and be aware of the potential presence of other CBD
analogs, which could possess psychotropic properties that
may not be desired [109]. It is also important to consider
that where CBD has been suggested as the root cause of sig-
nificant findings, there may in fact be an ‘entourage effect’
as other cannabinoids may be present [156]. From a safety
perspective, despite being reported to have a reasonably
low adverse effects profile, there appear to be significant
drug metabolism interactions, as CBD is metabolized by
CYP450 isoforms 2C19 and 3A4 [157, 158]. Approximately
60% of clinically prescribed medications are metabolized by
CYP3A4 and as a consequence there are suggestions that
CBD can increase the adverse effects profile of standard
medications such as clobazam used to treat epilepsy [130].
Subsequently, future research should investigate the efficacy
of CBD in its therapeutic role in pain and recovery manage-
ment, sports-related anxiolytic and sleep promoting effects,
and examine drug interactions and side effect profiles of
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S83
Cannabis and Athletic Performance
CBD supplementation. It is essential that studies begin to
further investigate the mechanistic properties of CBD (and
any ‘entourage effect’), as well as explore translatable mech-
anistic findings in-vivo.
5 Conclusions
Cannabis and individual cannabinoids have a clear capacity
to affect certain facets of human physiology; however, the
applicability of such physiological perturbations to affect
improvements in the health, performance, or recovery of
athletes remains incomplete owing to large knowledge gaps
and low-quality existing evidence stemming from substan-
tial barriers to conducting high quality cannabis research
[2, 3]. Herein, we have provided an overview of the existing
evidence and areas for future research. Unlike CBD, can-
nabis and THC are prohibited by WADA in-competition,
and while the cardiorespiratory effects at rest of cannabis
and THC are well described, both the short- and long-term
effects on the human capacity for exercise require well-con-
trolled, athlete-specific research, with applied performance
outcomes. Additional work will be required to understand
the dose–response of these effects, accounting for methods
of consumption, timing around exercise and cannabinoid
concentrations. Such data are essential for weighing the evi-
dence for or against prohibition both in and out of competi-
tion. The use of CBD by athletes is likely more relevant to
recovery during training and while in competition. CBD may
have some promise for improving athlete pain and recovery
through a number of potential mechanisms, although evi-
dence to support this to date is extremely limited. Moreover,
the use of CBD requires prudent attention to local regula-
tions and contamination with prohibited cannabinoids could
trigger doping violations.
Acknowledgements This supplement is supported by the Gatorade
Sports Science Institute (GSSI). The supplement was guest edited
by Lawrence L. Spriet, who convened a virtual meeting of the GSSI
Expert Panel in October 2020 and received honoraria from the GSSI,
a division of PepsiCo, Inc., for his participation in the meeting. Dr
Spriet received no honoraria for guest editing the supplement. Dr Spriet
suggested peer reviewers for each paper, which were sent to the Sports
Medicine Editor-in-Chief for approval, prior to any reviewers being
approached. Dr Spriet provided comments on each paper and made an
editorial decision based on comments from the peer reviewers and the
Editor-in-Chief. Where decisions were uncertain, Dr Spriet consulted
with the Editor-in-Chief.The views expressed in this manuscript are
those of the authors and do not necessarily reflect the position or policy
of PepsiCo, Inc.
Declarations
Funding This article is based on a presentation by Jamie Burr and
Graeme Close to the GSSI Expert Panel Virtual Meeting in October
2020. An honorarium for participation in the meeting and preparation
of this article was provided by the GSSI. No other sources of funding
were used to assist in the preparation of this article.
Conflicts of interest Graeme Close has received funding from Na-
turecan Ltd. Jamie Burr, Christian Cheung, Andreas Kasper and Scott
Gillham declare that they have no conflicts of interest relevant to the
content of this review.
Author contributions All authors contributed to drafting the manu-
script, and all authors edited and approved the final manuscript.
Open access This article is licensed under a Creative Commons Attri-
bution 4.0 International License, which permits use, sharing, adapta-
tion, distribution and reproduction in any medium or format, as long
as you give appropriate credit to the original author(s) and the source,
provide a link to the Creative Commons licence, and indicate if changes
were made. The images or other third party material in this article are
included in the article’s Creative Commons licence, unless indicated
otherwise in a credit line to the material. If material is not included in
the article’s Creative Commons licence and your intended use is not
permitted by statutory regulation or exceeds the permitted use, you will
need to obtain permission directly from the copyright holder. To view a
copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/.
References
1. Frankhauser M. History of Cannabis in Western medicine. In:
Grotterman F, Russo E, editors. Cannabis cannabinoids phar-
macol toxicol ther potential. Binghampton: Routledge; 2013.
p. 37.
2. Haney M. Perspectives on cannabis research—barriers and rec-
ommendations. JAMA Psychiat. 2020;77:994–5.
3. Martin JH, Hill C, Walsh A, Efron D, Taylor K, Kennedy M,
etal. Clinical trials with cannabis medicines—guidance for eth-
ics committees, governance officers and researchers to stream-
line ethics applications and ensuring patient safety: considera-
tions from the Australian experience. Trials BioMed Central.
2020;21:1–7.
4. Lorente FO, Peretti-Watel P, Grelot L. Cannabis use to enhance
sportive and non-sportive performances among French sport stu-
dents. Addict Behav. 2005;30:1382–91.
5. Peretti-Watel P, Guagliardo V, Verger P, Pruvost J, Mignon P,
Obadia Y. Sporting activity and drug use: alcohol, cigarette
and cannabis use among elite student athletes. Addiction.
2003;98:1249–56.
6. Brisola-Santos MB, de Gallinaro JG, Gil F, Sampaio-Junior B,
Marin MCD, de Andrade AG, etal. Prevalence and correlates of
cannabis use among athletes—A systematic review. Am J Addict.
2016;25:518–28.
7. Campian MD, Flis AE, Teramoto M, Cushman DM. Self-
Reported use and attitudes toward performance-enhancing
drugs in ultramarathon running. Wilderness Environ Med.
2018;29:330–7.
8. World Drug Report—Booklet 2: drug use and health conse-
quences. United Nations Publ. 2020.
9. Docter S, Khan M, Gohal C, Ravi B, Bhandari M, Gandhi R,
etal. Cannabis use and sport: a systematic review. Sports Health.
2020;12:189–99.
10. Amin MR, Ali DW. Pharmacology of medical cannabis. Adv Exp
Med Biol. 2019;1162:151–65.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S84 J.F.Burr et al.
11. Ashton CH. Pharmacology and effects of cannabis: A brief
review. Br J Psychiatry. 2001;178:101–6.
12. Pertwee R. Pharmacology of cannabinoid CB1 and CB2 recep-
tors. Pharmacol Ther. 1997;74:129–80.
13. Anand P, Whiteside G, Fowler CJ, Hohmann AG. Targeting CB2
receptors and the endocannabinoid system for the treatment of
pain. Brain Res Rev. 2009;60:255–66.
14. Niesink RJM, van Laar MW. Does cannabidiol protect against
adverse psychological effects of THC? Front Psychiatry.
2013;4:130.
15. Laprairie RB, Bagher AM, Kelly MEM, Denovan-Wright EM.
Cannabidiol is a negative allosteric modulator of the cannabinoid
CB1 receptor. Br J Pharmacol. 2015;172:4790–805.
16. Sparling PB, Giuffrida A, Piomelli D, Rosskopf L, Dietrich A.
Exercise activates the endocannabinoid system. NeuroReport.
2003;14:256–77.
17. Huestis MA, Sampson AH, Holicky BJ, Henningfield JE, Cone
EJ. Characterization of the absorption phase of marijuana smok-
ing. Clin Pharmacol Ther. 1992;52:31–41.
18. Schlienz NJ, Spindle TR, Cone EJ, Herrmann ES, Bigelow GE,
Mitchell JM, etal. Pharmacodynamic dose effects of oral can-
nabis ingestion in healthy adults who infrequently use cannabis.
Drug Alcohol Depend. 2020;211:107969.
19. Grotenhermen F. Pharmacokinetics and pharmacodynamics of
cannabinoids. Clin Pharmacokinet. 2003;42:327–60.
20. Kasper AM, Sparks SA, Hooks M, Skeer M, Webb B, Nia H,
etal. High prevalence of cannabidiol use within male pro-
fessional rugby union and league players : a quest for pain
relief and enhanced recovery. Int J Sport Nutr Exerc Metab.
2020;30:315–22.
21. Huestis MA, Mazzoni I, Rabin O. Cannabis in sport: anti-doping
perspective. Sport Med. 2011;41:949–66.
22. Jones RT. Cardiovascular system effects of marijuana. J Clin
Pharmacol. 2002;42:58S-63S.
23. Ribeiro LIG, Ind PW. Effect of cannabis smoking on lung func-
tion and respiratory symptoms: a structured literature review.
Prim Care Respir Med. 2016;26:1–8.
24. Crean RD, Crane NA, Mason BJ. An evidence based review of
acute and long-term effects of cannabis use on executive cogni-
tive functions. J Addict Med. 2011;5:1.
25. Pacher P, Steffens S, Haskó G, Schindler TH, Kunos G. Cardio-
vascular effects of marijuana and synthetic cannabinoids: the
good, the bad, and the ugly. Nat Rev Cardiol. 2018;15:151–66.
26. Hall W, Degenhardt L. Adverse health effects of non-medical
cannabis use. Lancet. 2009;374:1383–91.
27. Saugy M, Avois L, Saudan C, Robinson N, Giroud C, Mangin P,
etal. Cannabis and sport. Br J Sports Med. 2006;40:i13–5.
28. Goyal H, Awad HH, Ghali JK. Role of cannabis in cardiovascular
disorders. J Thorac Dis. 2017;9:2079–92.
29. Kvålseth TO. Effects of marijuana on human reaction time and
motor control. Percept Mot Skills. 1977;45:935–9.
30. Kennedy MC. Cannabis: exercise performance and sport. A sys-
tematic review. J Sci Med Sport. 2017;20:825–9.
31. Ware M, Jensen D, Barrette A, Vernec A, Derman W. Cannabis
and the health and performance of the elite athlete. Clin J Sport
Med. 2018;1992:480–4.
32. Charron J, Carey V, Marcotte L’Heureux V, Roy P, Comtois AS,
Ferland PM. Acute effects of cannabis consumption on exercise
performance: a systematic and umbrella review. J Sports Med
Phys Fitness. 2021;61:551–61.
33. Pesta DH, Angadi SS, Burtscher M, Roberts CK. The effects of
caffeine, nicotine, ethanol, and tetrahydrocannabinol on exercise
performance. Nutr Metab. 2013;10:1–15.
34. Campos DR, Yonamine M, De Moraes Moreau RL. Marijuana
as doping in sports. Sport Med. 2003;33:395–9.
35. Huestis MA. Cannabis (marijuana)—effects on human behavior
and performance. Forensic Sci Rev. 2002;14:16–60.
36. Gillman AS, Hutchison KE, Bryan AD. Cannabis and exercise
science: a commentary on existing studies and suggestions for
future directions. Sport Med. 2015;45:1357–63.
37. Lisano JK, Kisiolek JN, Smoak P, Phillips KT, Stewart LK.
Chronic cannabis use and circulating biomarkers of neural
health, stress, and inflammation in physically active individuals.
Appl Physiol Nutr Metab. 2020;45:258–63.
38. Maksud MG, Baron A. Physiological responses to exercise in
chronic cigarette and marijuana users. Eur J Appl Physiol Occup
Physiol. 1980;43:127–34.
39. Lisano JK, Smith JD, Mathias AB, Christensen M, Smoak P,
Phillips KT, etal. Performance and health-related characteristics
of physically active males using marijuana. J Strength Cond Res.
2019;33:1658–68.
40. Wade NE, Gilbart E, Swartz AM, Lisdahl KM. Assessing aero-
bic fitness level in relation to affective and behavioral function-
ing in emerging adult cannabis users. Int J Ment Health Addict.
2019;2019:1–14.
41. Steadward RD, Singh M. The effects of smoking marihuana on
physical performance. Med Sci Sports Exerc. 1975;7:309–11.
42. Aronow WS, Cassidy J. Effect of marihuana and placebo-
marihuana smoking on angina pectoris. N Engl J Med.
1974;291:65–7.
43. Avakian EV, Horvath SM, Michael ED, Jacobs S. Effect of mari-
huana on cardiorespiratory responses to submaximal exercise.
Clin Pharmacol Ther. 1979;26:777–81.
44. Renaud AM, Cormier Y. Acute effects of marihuana smok-
ing on maximal exercise performance. Med Sci Sport Exerc.
1986;18:685–9.
45. Aronow WS, Cassidy J. Effect of smoking marihuana and of a
high-nicotine cigarette on angina pectoris. Clin Pharmacol Ther.
1975;17:549–54.
46. Abdallah SJ, Smith BM, Ware MA, Moore M, Li PZ, Bourbeau
J, etal. Effect of vaporized cannabis on exertional breathlessness
and exercise endurance in advanced chronic obstructive pulmo-
nary disease: a randomized controlled trial. Ann Am Thorac Soc.
2018;15:1146–58.
47. Preuss UW, Watzke AB, Zimmermann J, Wong JWM, Schmidt
CO. Cannabis withdrawal severity and short-term course among
cannabis-dependent adolescent and young adult inpatients. Drug
Alcohol Depend Elsevier. 2010;106:133–41.
48. Sanders D, van Erp T. The physical demands and power profile of
professional men’s cycling races: an updated review. Int J Sports
Physiol Perform. 2020;1:1–10.
49. Borg GA, Dahlstrom H. The reliability and validity of a physical
work test. Acta Physiol Scand. 1962;55:353–61.
50. Hawley JA, Noakes TD. Peak power output predicts maxi-
mal oxygen uptake and. Eur J Appl Physiol Occup Physiol.
1992;65:79–83.
51. Bell DG, Jacobs I, McLellan TM, Zamecnik J. Reducing the
dose of combined caffeine and ephedrine preserves the ergogenic
effect. Aviat Sp Environ Med. 2000;71:415–9.
52. Bell DG, Mclellan TM, Sabiston CM. Effect of ingesting caffeine
and ephedrine on 10-km run performance. Med Sci Sport Exerc.
2001;34:344–9.
53. Weiss JL, Watanabe AM, Lemberger L, Tamarkin NR, Cardon
PV. Cardiovascular effects of delta-9-tetrahydrocannabinol in
man. Clin Pharmacol Ther. 1972;13:671–84.
54. Perez-Reyes M, Timmons MC, Lipton MA. Intravenous injection
in man of delta-9-tetrahydrocannabinol and 11-hydroxy-delta-
9-tetrahydrocannabinol. Science. 1972;177:633–5.
55. Kochar MS, Hosko MJ. Electrocardiographic effects of mari-
huana. JAMA. 1973;225:25–7.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S85
Cannabis and Athletic Performance
56. Roth WT, Tinklenberg JR, Kopell BS, Hollister LE. Continuous
electrocardiographic monitoring during marihuana intoxication.
Clin Pharmacol Ther. 1973;14:533–40.
57. Clark CS, Greene C, Karr G, MacCannell K, Milstein S. Cardio-
vascular effects of marihuana in man. Can J Physiol Pharmacol.
1974;52:706–19.
58. Karniol IG, Shirakawa I, Takahashi RN, Knobel E, Musty RE.
Effects of delta-9-tetrahydrocannabinol and cannabinol in man.
Pharmacology. 1975;13:502–12.
59. Prakash R, Aronow WS, Warren M, Laverty W, Gottschalk
LA. Effects of marihuana and placebo marihuana smoking
on hemodynamics in coronary disease. Clin Pharmacol Ther.
1975;18:90–5.
60. Benowitz NL, Jones RT. Cardiovascular effects of prolonged
delta-9-tetrahydrocannabinol ingestion. Clin Pharmacol Ther.
1975;18:287–97.
61. Malit LA, Johnstone RE, Bourke DI, Kulp RA, Klein V, Smith
TC. Intravenous delta-9-tetrahydrocannabinol: effects on ven-
tilatory control and cardiovascular dynamics. Anesthesiology.
1975;42:666–73.
62. Bernstein JG, Kuehnle JC, Mendelson JH. Medical implications
of marijuana use. Am J Drug Alcohol Abuse. 1976;3:347–61.
63. Gregg JM, Campbell RL, Levin KJ, Ghia J, Elliott RA. Cardio-
vascular effects of cannabinol during oral surgery. Anesth Analg.
1976;55:203–13.
64. Tashkin DP, Levisman JA, Abbasi AS, Shapiro BJ, Ellis NM.
Short term effects of smoked marihuana on left ventricular func-
tion in man. Chest. 1977;72:20–6.
65. Sulkowski A, Vachon L, Rich ES. Propranolol effects on
acute marihuana intoxication in man. Psychopharmacology.
1977;52:47–53.
66. Mendelson JH, Mello NK. Reinforcing properties of oral
Δ9-tetrahydrocannabinol, smoked marijuana, and nabilone:
influence of previous marijuana use. Psychopharmacology.
1984;83:351–6.
67. Lex BW, Mendelson JH, Bavli S, Harvey K, Mello NK. Effects
of acute marijuana smoking on pulse rate and mood states in
women. Psychopharmacology. 1984;84:178–87.
68. Kelly TH, Foltin RW, Fischman MW. Effects of smoked mari-
juana on heart rate, drug ratings and task performance by
humans. Behav Pharmacol. 1993;4:167–78.
69. Huestis MA, Boyd SJ, Heishman SJ, Preston KL, Bonnet D, Le
Fur G, etal. Single and multiple doses of rimonabant antagonize
acute effects of smoked cannabis in male cannabis users. Psy-
chopharmacol Berl. 2007;194:505–15.
70. D’Souza DC, Ranganathan M, Braley G, Gueorguieva R, Zimolo
Z, Cooper T, etal. Blunted psychotomimetic and amnestic effects
of Δ-9-tetrahydrocannabinol in frequent users of cannabis. Neu-
ropsychopharmacology. 2008;33:2505–16.
71. Cooper ZD, Haney M. Comparison of subjective, pharmacoki-
netic, and physiologic effects of marijuana smoked as joints and
blunts. Drug Alcohol Depend. 2009;103:107–13.
72. Zuurman L, Roy C, Schoemaker RC, Amatsaleh A, Guimaeres
L, Pinquier JL, etal. Inhibition of THC-induced effects on the
central nervous system and heart rate by a novel CB1 receptor
antagonist AVE1625. J Psychopharmacol. 2010;24:363–71.
73. Klumpers LE, Roy C, Ferron G, Turpault S, Poitiers F, Pinquier
JL, etal. Surinabant, a selective cannabinoid receptor type 1
antagonist, inhibits Δ9-tetrahydrocannabinol-induced central
nervous system and heart rate effects in humans. Br J Clin Phar-
macol. 2013;76:65–77.
74. Englund A, Atakan Z, Kralj A, Tunstall N, Murray R, Morrison
P. The effect of five day dosing with THCV on THC-induced
cognitive, psychological and physiological effects in healthy
male human volunteers: a placebo-controlled, double-blind,
crossover pilot trial. J Psychopharmacol. 2016;30:140–51.
75. Kanakis C, Pouget JM, Rosen KM. Lack of cardiovascular effects
of delta-9-tetrahydrocannabinol in chemically denervated men.
Ann Intern Med. 1979;91:571–4.
76. Gash A, Karliner JS, Janowsky D, Lake CR. Effects of smoking
marihuana on left ventricular performance and plasma norepi-
nephrine. Ann Intern Med. 1978;89:448–52.
77. Benowitz NL, Jones RT. Prolonged delta-9-tetrahydrocannab-
inol ingestion effects of sympathomimetic amines and auto-
nomic blockades. Clin Pharmacol Ther. 1977;21:336–42.
78. Benowitz NL, Rosenberg J, Rogers W, Bachman J, Jones RT.
Cardiovascular effects of intravenous delta-9-tetrahydrocan-
nabinol: autonomic nervous mechanisms. Clin Pharmacol
Ther. 1979;25:440–6.
79. Kanakis C, Pouget JM, Rosen KM. The effects of delta-9-tet-
rahydrocannabinol (cannabis) on cardiac performance with and
without beta blockade. Circulation. 1976;53:703–7.
80. Renault PF, Schuster CR, Freedman DX, Sikic B, de Mello
DN, Halaris A. Repeat administration of marihuana smoke to
humans. Arch Gen Psychiatry. 1974;31:95–102.
81. Isbell H, Gorodetzsky CW, Jasinski D, Claussen U, Spulak FV,
Korte F. Effects of (-)Δ9-trans-tetrahydrocannabinol in man.
Psychopharmacologia. 1967;11:184–8.
82. Renault PF, Schuster CR, Heinrich R, Freeman DX. Mari-
huana: standardized smoke administration and dose effect
curves on heart Rate in humans. Science. 1971;174:589–91.
83. Johnson S, Domino FE. Some cardiovascular effects of mari-
huana smoking in normal volunteers. Clin Pharmacol Ther.
1971;12:762–8.
84. Martz R, Brown DJ, Forney RB, Sright TP, Kiplinger GF,
Rodda BE. Propranolol antagonism of marihuana induced
tachycardia. Life Sci. 1972;11:999–1005.
85. Beaconsfield P, Ginsburg J, Rainsbury R. Marihuana smoking
cardiovascular effects in man and possible mechanisms. N Engl
J Med. 1972;287:209–12.
86. Gobel FL, Norstrom LA, Nelson RR, Jorgensen CR, Wang Y.
The rate-pressure product as an index of myocardial oxygen
consumption during exercise in patients with angina pectoris.
Circulation. 1978;57:549–56.
87. Moir D, Rickert WS, Levasseur G, Larose Y, Maertens
R, White P, etal. A comparison of mainstream and side-
stream marijuana and tobacco cigarette smoke produced
under two machine smoking conditions. Chem Res Toxicol.
2008;21:494–502.
88. Johnstone RE, Lief PL, Kulp RA, Smith TC. Combination of
delta 9-tetrahydrocannabinol with oxymorphone or pentobarbi-
tal. Anesthesiology. 1975;42:674–84.
89. Gorelick DA, Heishman SJ, Preston KL, Nelson RA, Moolchan
ET, Huestis MA. The cannabinoid CB1 receptor antagonist
rimonabant attenuates the hypotensive effect of smoked mari-
juana in male smokers. Am Heart J. 2006;151:754.e1-754.e5.
90. Pihl RO, Shea D, Caron P. The effect of marihuana intoxication
on blood pressure. J Clin Psychol. 1978;34:569–70.
91. Mortensen SP, Damsgaard R, Dawson EA, Secher NH, González-
Alonso J. Restrictions in systemic and locomotor skeletal muscle
perfusion, oxygen supply and VO2 during high-intensity whole-
body exercise in humans. J Physiol. 2008;586:2621–35.
92. Roger VL, Pellikka PA, Oh JK, Miller FA, Seward JB, Tajik
AJ. Stress echocardiography. Part I. Exercise echocardiography:
techniques, implementation, clinical applications, and correla-
tions. Mayo Clin Proc. 1995;70:5–15.
93. La Gerche A, Claessen G, Van De Bruaene A, Pattyn N, Van
Cleemput J, Gewillig M, etal. Cardiac MRI: a new gold stand-
ard for ventricular volume quantification during high-intensity
exercise. Circ Cardiovasc Imaging. 2013;6:329–38.
94. Geyer H, Caracciolo G, Abe H, Wilansky S, Carerj S, Gentile
F, etal. Assessment of myocardial mechanics using speckle
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S86 J.F.Burr et al.
tracking echocardiography: fundamentals and clinical applica-
tions. J Am Soc Echocardiogr. 2010;23:351–69.
95. Stöhr EJ, Shave RE, Baggish AL, Weiner RB. Left ventricular
twist mechanics in the context of normal physiology and cardio-
vascular disease: a review of studies using speckle tracking echo-
cardiography. Am J Physiol Circ Physiol. 2016;311:H633–44.
96. Khanji MY, Jensen MT, Kenawy AA, Raisi-estabragh Z, Paiva
JM, Aung N, etal. Association between recreational cannabis use
and cardiac structure and function. JACC Cardiovasc Imaging.
2020;13:886–8.
97. Cheung CP, Coates AM, Millar PJ, Burr JF. Habitual cannabis
use is associated with altered cardiac mechanics and arterial stiff-
ness, but not endothelial function in young healthy smokers. J
Appl Physiol. 2021;130:660–70.
98. Bonz A, Laser M, Kullmer S, Kniesch S, Babin-Ebell J, Popp V,
etal. Cannabinoids acting on CB1 receptors decrease contractile
performance in human atrial muscle. J Cardiovasc Pharmacol.
2003;41:657–64.
99. Steffens S, Veillard NR, Arnaud C, Pelli G, Burger F, Staub C,
etal. Low dose oral cannabinoid therapy reduces progression of
atherosclerosis in mice. Nature. 2005;434:782–6.
100. Huestis MA, Gorelick DA, Heishman SJ, Preston KL, Nelson
RA, Moolchan ET, etal. Blockade of effects of smoked mari-
juana by the CB1-selective cannabinoid receptor antagonist
SR141716. Arch Gen Psychiatry. 2001;58:322–8.
101. Pletcher M, Vittinghoff E, Kalhan R, Richman J, Safford M, Sid-
ney S, etal. Association between marijuana exposure and pulmo-
nary function over 20 years. J Am Med Assoc. 2012;307:173–81.
102. Tashkin DP. Effects of marijuana smoking on the lung. Ann Am
Thorac Soc. 2013;10:239–47.
103. Tashkin DP, Shapiro BJ, Frank IM. Acute pulmonary physiologic
effects of smoked marijuana and oral delta-9-tetrahydrocannabi-
nol in healthy young men. N Engl J Med. 1973;289:336–41.
104. Tashkin DP, Reiss S, Shapiro BJ, Calvarese B, Olsen JL,
Lodge JW. Bronchial effects of aerosolized Δ9 tetrahydrocan-
nabinol in healthy and asthmatic subjects. Am Rev Respir Dis.
1977;115:57–65.
105. Wolfarth B, Wuestenfeld JC, Kindermann W. Ergogenic effects
of inhaled β2-agonists in non-asthmatic athletes. Endocrinol
Metab Clin North Am. 2010;39:75–87.
106. Wold-Anti Doping Agency (WADA). Prohibited List. World
Anti-Doping. 2016. pp. 1–116.
107. Riiser A, Stensrud T, Stang J, Andersen LB. Can β2-agonists
have an ergogenic effect on strength, sprint or power perfor-
mance? Systematic review and meta-analysis of RCTs. Br J
Sports Med. 2020;54:1351–9.
108. Goodman S, Wadsworth E, Leos-Toro C, Hammond D. Preva-
lence and forms of cannabis use in legal vs. illegal recreational
cannabis markets. Int J Drug Policy. 2020;102658:1–10.
109. Morales P, Reggio PH, Jagerovic N. An overview on medicinal
chemistry of synthetic and natural derivatives of cannabidiol.
Front Pharmacol. 2017;8:1–18.
110. McCartney D, Benson MJ, Desbrow B, Irwin C, Suraev A,
McGregor IS. Cannabidiol and sports performance: a narrative
review of relevant evidence and recommendations for future
research. Sport Med. 2020;6:1–18.
111. WADA. Summary of major modifications and explanatory notes:
substances and methods prohibited at all times. World Anti-Dop-
ing Agency. 2018. pp. 1–2.
112. Walsh NP, Halson SL, Sargent C, Roach GD, Nédélec M, Gupta
L, etal. Sleep and the athlete: narrative review and 2021 expert
consensus recommendations. Br J Sports Med. 2021;55:356–68.
113. Dunican IC, Walsh J, Higgins CC, Jones MJ, Maddison K, Cald-
well JA, etal. Prevalence of sleep disorders and sleep problems
in an elite super rugby union team. J Sports Sci. 2019;37:950–7.
114. Tuomilehto H, Vuorinen VP, Penttilä E, Kivimäki M, Vuorenmaa
M, Venojärvi M, etal. Sleep of professional athletes: underex-
ploited potential to improve health and performance. J Sports Sci.
2017;35:704–10.
115. Fullagar HHK, Duffield R, Skorski S, Coutts AJ, Julian R, Meyer
T. Sleep and recovery in team sport: current sleep-related issues
facing professional team-sport athletes. Int J Sports Physiol Per-
form. 2015;10:950–7.
116. Fullagar H, Skorski S, Duffield R, Meyer T. The effect of an
acute sleep hygiene strategy following a late-night soccer match
on recovery of players. Chronobiol Int. 2016;33:490–505.
117. Fowler PM, Knez W, Crowcroft S, Mendham AE, Miller J, Sar-
gent C, etal. Greater Effect of east versus west travel on jet
lag, sleep, and team sport performance. Med Sci Sports Exerc.
2017;49:2548–61.
118. Erlacher D, Ehrlenspiel F, Adegbesan OA, El-Din HG. Sleep
habits in German athletes before important competitions or
games. J Sports Sci. 2011;29:859–66.
119. Lastella M, Lovell GP, Sargent C. Athletes’ precompetitive sleep
behaviour and its relationship with subsequent precompetitive
mood and performance. Eur J Sport Sci. 2014;14:S123–30.
120. Sargent C, Halson S, Roach GD. Sleep or swim? Early-morning
training severely restricts the amount of sleep obtained by elite
swimmers. Eur J Sport Sci. 2014;14:S10-315.
121. Romyn G, Robey E, Dimmock JA, Halson SL, Peeling P. Sleep,
anxiety and electronic device use by athletes in the training and
competition environments. Eur J Sport Sci. 2016;16:301–8.
122. Shannon S, Opila-Lehman J. Effectiveness of cannabidiol oil for
pediatric anxiety and insomnia as part of posttraumatic stress
disorder: a case report. Perm J. 2016;20:108–11.
123. Chagas MHN, Eckeli AL, Zuardi AW, Pena-Pereira MA,
Sobreira-Neto MA, Sobreira ET, etal. Cannabidiol can improve
complex sleep-related behaviours associated with rapid eye
movement sleep behaviour disorder in Parkinson’s disease
patients: a case series. J Clin Pharm Ther. 2014;39:564–6.
124. Carlini EA, Cunha JM. Hypnotic and antiepileptic effects of can-
nabidiol. J Clin Pharmacol. 1981;21:417S-427S.
125. Linares IMP, Guimaraes FS, Eckeli A, Crippa ACS, Zuardi AW,
Souza JDS, etal. No acute effects of Cannabidiol on the sleep-
wake cycle of healthy subjects: a randomized, double-blind, pla-
cebo-controlled, crossover study. Front Pharmacol. 2018;9:1–8.
126. Owens DJ, Twist C, Cobley JN, Howatson G, Close GL. Exer-
cise-induced muscle damage: what is it, what causes it and what
are the nutritional solutions? Eur J Sport Sci. 2019;19:71–85.
127. Julian R, Page RM, Harper LD. The effect of fixture congestion
on performance during professional male soccer match-play:
a systematic critical review with meta-analysis. Sport Med.
2021;51:255–73.
128. Tsitsimpikou C, Jamurtas A, Fitch K, Papalexis P, Tsarouhas K.
Medication use by athletes during the Athens 2004 Paralympic
Games. Br J Sports Med. 2009;43:1062–6.
129. Bertolini A, Ottani A, Sandrini M. Dual acting anti-inflammatory
drugs: A reappraisal. Pharmacol Res. 2001;44:437–50.
130. Devinsky O, Thiele EA, Wright S, Checketts D, Morrison
G, Dunayevich E, etal. Cannabidiol efficacy independent of
clobazam: meta-analysis of four randomized controlled trials.
Acta Neurol Scand. 2020;142:531–40.
131. Chesney E, Oliver D, Green A, Sovi S, Wilson J, Englund A,
etal. Adverse effects of cannabidiol: a systematic review and
meta-analysis of randomized clinical trials. Neuropsychophar-
macology. 2020;2020:1–8.
132. Huestis MA, Solimini R, Pichini S, Pacifici R, Carlier J, Busardò
FP. Cannabidiol adverse effects and toxicity. Curr Neuropharma-
col. 2019;17:974–89.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
S87
Cannabis and Athletic Performance
133. Mlost J, Bryk M, Starowicz K. Cannabidiol for pain treatment:
focus on pharmacology and mechanism of action. Int J Mol Sci.
2020;21:1–22.
134. Naftali T, Mechulam R, Marii A, Gabay G, Stein A, Bronshtain
M, etal. Low-dose cannabidiol is safe but not effective in the
treatment for Crohn’s disease, a randomized controlled trial. Dig
Dis Sci. 2017;62:1615–20.
135. Irving PM, Iqbal T, Nwokolo C, Subramanian S, Bloom S,
Prasad N, etal. A randomized, double-blind, placebo-controlled,
parallel-group, pilot study of cannabidiol-rich botanical extract in
the symptomatic treatment of Ulcerative Colitis. Inflamm Bowel
Dis. 2018;24:714–24.
136. Cochrane-Snyman KC, Cruz C, Morales J, Coles M. The effects
of cannabidiol oil on noninvasive measures of muscle damage in
men. Med Sci Sport Exerc. 2021;53:1460–72.
137. Isenmann E, Veit S, Diel P. Effects Of cannabidiol supplementa-
tion on the skeletal muscle regeneration after intensive resistance
training. Med Sci Sport Exerc. 2020;52:766–766.
138. Karr JE, Areshenkoff CN, Garcia-Barrera MA. The neuropsy-
chological outcomes of concussion: a systematic review of meta-
analyses on the cognitive sequelae of mild traumatic brain injury.
Neuropsychology. 2014;28:321–36.
139. Barth JT, Freeman JR, Broshek DK, Varney RN. Acceleration-
deceleration sport-related concussion: the gravity of it all. J Athl
Train. 2001;36:253–6.
140. Gardner AJ, Iverson GL, Williams WH, Baker S, Stanwell P.
A systematic review and meta-analysis of concussion in Rugby
Union. Sport Med. 2014;44:1717–31.
141. Gardner A, Iverson GL, Levi CR, Schofield PW, Kay-Lambkin F,
Kohler RMN, etal. A systematic review of concussion in rugby
league. Br J Sports Med. 2015;49:495–8.
142. Kerr ZY, Roos KG, Djoko A, Dalton SL, Broglio SP, Marshall
SW, etal. Epidemiologic measures for quantifying the incidence
of concussion in national collegiate athletic association sports. J
Athl Train. 2017;52:167–74.
143. Lessley DJ, Kent RW, Funk JR, Sherwood CP, Cormier JM,
Crandall JR, etal. Video analysis of reported concussion events
in the National Football League during the 2015–2016 and 2016–
2017 seasons. Am J Sports Med. 2018;46:3502–10.
144. Bernick C, Hansen T, Ng W, Williams V, Goodman M, Nalepa B,
etal. Concussion occurrence and recognition in professional box-
ing and MMA matches: toward a concussion protocol in combat
sports. Phys Sportsmed. 2021;2021:1–7.
145. McCrory P, Meeuwisse WH, Aubry M, Cantu B, Dvořák J, Eche-
mendia RJ, etal. Consensus statement on concussion in sport:
the 4th International Conference on Concussion in Sport held in
Zurich, November 2012. Br J Sports Med. 2013;2013:250–8.
146. Dean PJA, Sato JR, Vieira G, McNamara A, Sterr A. Long-term
structural changes after mTBI and their relation to post-concus-
sion symptoms. Brain Inj. 2015;29:1211–8.
147. Belardo C, Iannotta M, Boccella S, Rubino RC, Ricciardi F,
Infantino R, etal. Oral cannabidiol prevents allodynia and neu-
rological dysfunctions in a mouse model of mild traumatic brain
injury. Front Pharmacol. 2019;10:352.
148. Pazos MR, Cinquina V, Gómez A, Layunta R, Santos M,
Fernández-Ruiz J, et al. Cannabidiol administration after
hypoxia-ischemia to newborn rats reduces long-term brain injury
and restores neurobehavioral function. Neuropharmacology.
2012;63:776–83.
149. Pazos MR, Mohammed N, Lafuente H, Santos M, Martínez-
Pinilla E, Moreno E, etal. Mechanisms of cannabidiol neuropro-
tection in hypoxic-ischemic newborn pigs: Role of 5HT1A and
CB2 receptors. Neuropharmacology. 2013;71:282–91.
150. Lastres-Becker I, Molina-Holgado F, Ramos JA, Mechoulam R,
Fernández-Ruiz J. Cannabinoids provide neuroprotection against
6-hydroxydopamine toxicity invivo and invitro: relevance to
Parkinson’s disease. Neurobiol Dis. 2005;19:96–107.
151. Carrier EJ, Auchampach JA, Hillard CJ. Inhibition of an equili-
brative nucleoside transporter by cannabidiol: a mechanism of
cannabinoid immunosuppression. Proc Natl Acad Sci USA.
2006;103:7895–900.
152. Nair A, Jacob S. A simple practice guide for dose conversion
between animals and human. J Basic Clin Pharm. 2016;7:27.
153. Gurley BJ, Murphy TP, Gul W, Walker LA, ElSohly M. Content
versus label claims in cannabidiol (CBD)-containing products
obtained from commercial outlets in the state of Mississippi. J
Diet Suppl. 2020;17:599–607.
154. Wong A, Montebello ME, Norberg MM, Rooney K, Lintzeris N,
Bruno R, etal. Exercise increases plasma THC concentrations in
regular cannabis users. Drug Alcohol Depend. 2013;133:763–7.
155. Gunasekaran N, Long LE, Dawson BL, Hansen GH, Richardson
DP, Li KM, etal. Reintoxication: The release of fat-stored Δ 9-
tetrahydrocannabinol (THC) into blood is enhanced by food dep-
rivation or ACTH exposure. Br J Pharmacol. 2009;158:1330–7.
156. Russo EB. The case for the entourage effect and conventional
breeding of clinical cannabis: no “Strain”, no gain. Front Plant
Sci. 2019;9:1969.
157. Stout SM, Cimino NM. Exogenous cannabinoids as substrates,
inhibitors, and inducers of human drug metabolizing enzymes:
a systematic review. Drug Metab Rev. 2014;46:86–95.
158. Jiang R, Yamaori S, Takeda S, Yamamoto I, Watanabe K. Iden-
tification of cytochrome P450 enzymes responsible for metab-
olism of cannabidiol by human liver microsomes. Life Sci.
2011;89:165–70.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
1.
2.
3.
4.
5.
6.
Terms and Conditions
Springer Nature journal content, brought to you courtesy of Springer Nature Customer Service Center GmbH (“Springer Nature”).
Springer Nature supports a reasonable amount of sharing of research papers by authors, subscribers and authorised users (“Users”), for small-
scale personal, non-commercial use provided that all copyright, trade and service marks and other proprietary notices are maintained. By
accessing, sharing, receiving or otherwise using the Springer Nature journal content you agree to these terms of use (“Terms”). For these
purposes, Springer Nature considers academic use (by researchers and students) to be non-commercial.
These Terms are supplementary and will apply in addition to any applicable website terms and conditions, a relevant site licence or a personal
subscription. These Terms will prevail over any conflict or ambiguity with regards to the relevant terms, a site licence or a personal subscription
(to the extent of the conflict or ambiguity only). For Creative Commons-licensed articles, the terms of the Creative Commons license used will
apply.
We collect and use personal data to provide access to the Springer Nature journal content. We may also use these personal data internally within
ResearchGate and Springer Nature and as agreed share it, in an anonymised way, for purposes of tracking, analysis and reporting. We will not
otherwise disclose your personal data outside the ResearchGate or the Springer Nature group of companies unless we have your permission as
detailed in the Privacy Policy.
While Users may use the Springer Nature journal content for small scale, personal non-commercial use, it is important to note that Users may
not:
use such content for the purpose of providing other users with access on a regular or large scale basis or as a means to circumvent access
control;
use such content where to do so would be considered a criminal or statutory offence in any jurisdiction, or gives rise to civil liability, or is
otherwise unlawful;
falsely or misleadingly imply or suggest endorsement, approval , sponsorship, or association unless explicitly agreed to by Springer Nature in
writing;
use bots or other automated methods to access the content or redirect messages
override any security feature or exclusionary protocol; or
share the content in order to create substitute for Springer Nature products or services or a systematic database of Springer Nature journal
content.
In line with the restriction against commercial use, Springer Nature does not permit the creation of a product or service that creates revenue,
royalties, rent or income from our content or its inclusion as part of a paid for service or for other commercial gain. Springer Nature journal
content cannot be used for inter-library loans and librarians may not upload Springer Nature journal content on a large scale into their, or any
other, institutional repository.
These terms of use are reviewed regularly and may be amended at any time. Springer Nature is not obligated to publish any information or
content on this website and may remove it or features or functionality at our sole discretion, at any time with or without notice. Springer Nature
may revoke this licence to you at any time and remove access to any copies of the Springer Nature journal content which have been saved.
To the fullest extent permitted by law, Springer Nature makes no warranties, representations or guarantees to Users, either express or implied
with respect to the Springer nature journal content and all parties disclaim and waive any implied warranties or warranties imposed by law,
including merchantability or fitness for any particular purpose.
Please note that these rights do not automatically extend to content, data or other material published by Springer Nature that may be licensed
from third parties.
If you would like to use or distribute our Springer Nature journal content to a wider audience or on a regular basis or in any other manner not
expressly permitted by these Terms, please contact Springer Nature at
onlineservice@springernature.com
Available via license: CC BY 4.0
Content may be subject to copyright.
Content uploaded by Jamie F Burr
Author content
All content in this area was uploaded by Jamie F Burr on Sep 14, 2021
Content may be subject to copyright.
